Analysis of trophic networks and carbon flows in south-eastern Baltic coastal ecosystems

Progress in Oceanography 81 (2009) 111–131

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Progress in Oceanography

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Analysis of trophic networks and carbon flows in south-eastern Baltic coastalecosystems

Maciej T. Tomczak a,f,*, Bärbel Müller-Karulis d, Leili Järv b, Jonne Kotta b, Georg Martin b, Atis Minde c,Arno Põllumäe b, Arturas Razinkovas e, Solvita Strake d, Martynas Bucas e, Thorsten Blenckner g

a Sea Fisheries Institute, Kollataja 1 str., 81-332 Gdynia, Polandb Estonian Marine Institute, University of Tartu, 10a Mäealuse Street, Tallinn 12618, Estoniac Latvian Fish Resources Agency, 6 Daugavgrivas, LV-1048 Riga, Latviad Latvian Institute of Aquatic Ecology, 8 Daugavgrivas, LV-1048 Riga, Latviae Coastal Research and Planning Institute (CORPI), Klaipeda University, Manto 84, LT-5802 Klaipeda, Lithuaniaf Baltic NEST Institute, DTU-AQUA, J�gersborg Alle 1, Charlottenlund Castle, 2929 Charlottenlund, Denmarkg Baltic NEST Institute, Stockholm Resilience Centre, Stockholm University, S-106 91, Stockholm, Sweden

a r t i c l e i n f o a b s t r a c t

Available online 3 May 2009

0079-6611/$ - see front matter � 2009 Elsevier Ltd. Adoi:10.1016/j.pocean.2009.04.017

* Corresponding author. Address: Technical UnivInstitute of Aquatic Resources, J�gersborg Alle 1,Charlottenlund, Denmark.

E-mail address: [email protected] (M.T. Tomczak).

Carbon flows in five south-eastern Baltic coastal ecosystems (Puck Bay, Curonian Lagoon, Lithuaniancoast, Gulf of Riga coast and Pärnu Bay) were compared on the basis of ECOPATH models using 12 com-mon functional groups. The studied systems ranged from the hypertrophic Curonian Lagoon to the meso-trophic Gulf of Riga coast. Interestingly, we found that macrophytes were not consumed by grazers, butrather channelled into the detritus food chain. In all ecosystems fisheries had far reaching impacts ontheir target species and on the food-web in general. In particular, benthic food-webs were partly affectedby indirect fisheries effects. For example, fisheries tend to change the biomass of piscivorous fish, causinga cascading effect on benthivorous fish and macrozoobenthos. These cascades are ecosystem specific andneed to be considered when using benthic invertebrates as productivity and eutrophication indicators.Odum’s maturity attributes allowed a ranking of costal ecosystems according to their maturity. Namely,the community development decreased in the following order: Pärnu Bay > Gulf of Riga coast > Lithua-nian coast > Puck Bay > Curonian Lagoon.

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1. Introduction

Previous modelling work on Baltic Sea food-webs focused onpelagic ecosystems of deep-water areas (Harvey et al., 2003; Sand-berg et al., 2000; Jarre-Teichmann, 1995). Further, Witek (1995)calculated carbon flows and the utilization of primary productionin the Gdansk basin, but without particular attention to the shal-low coastal waters. Intercomparison of ecosystems, in particularthose located close to each other, allows identifying similaritiesand dissimilarities in energy and matter flows through food-webs.Trophic network modelling has been used as a tool to compare eco-systems by identifying internal relationships critical to their func-tioning and trophic and development stages (e.g. Kautsky andKautsky, 1995a,b). ECOPATH software is becoming increasinglypopular to perform food-web modelling (Christensen et al.,2004). Based on ECOPATH simulations, network indices and carbon

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ersity of Denmark, NationalCharlottenlund Castle, 2929

flows can be derived to quantify energy transfer efficiency throughthe entire food-web (Christensen et al., 2004).

Comparative network analyses of different ecosystems allowthe quantification of important direct and indirect food-web inter-actions and indicate the impact of human influences (e.g. fisheries,see Villanueva et al., 2006; Coll et al., 2006). In general, a compar-ative network analysis may examine carbon flows (Leontief, 1951;Hannon, 1973), cycling of organic matter (Finn, 1976), informationtheory (Ulanowicz, 1986) and thus offers a formal approach foranalyzing ecosystem structure (Baird and Ulanowicz, 1993).

The aim of this work is to analyze the interactions among bio-logical components and the functioning of food-webs of fivesouth-eastern Baltic coastal ecosystems, i.e. Puck Bay, CuronianLagoon, Lithuanian coast, Gulf of Riga coast and Pärnu Bay, byusing the ECOPATH approach. Focus is attributed to the quantifica-tion of carbon flows and transfer efficiencies among trophic levelsas well as to the identifications of the most important trophody-namic links occurring between the 12 common functional groups(Christensen, 1998). The results may provide an important inputto the ICES Working Group of Integrated Assessment of the BalticSea (Anon, 2007), and may further provide background informa-

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112 M.T. Tomczak et al. / Progress in Oceanography 81 (2009) 111–131

tion to multi-species conservation and management decisions(Baird and Ulanowicz, 1993) of coastal Baltic ecosystems.

2. Materials and methods

2.1. Study areas

The study areas span the entire south-eastern coast of the BalticSea (Fig. 1), namely Puck Bay in the Gulf of Gdansk (Puck Bay), theCuronian Lagoon, the Lithuanian Baltic Proper coast (Lithuaniancoast), an exposed area on the eastern shore of the Gulf of Riga (Gulfof Riga coast) and Pärnu Bay, a shallow bay in the Gulf of Riga north ofthe Gulf of Riga coast site. The study sites range from (a) relativelyopen coastlines (Lithuanian coast, Gulf of Riga coast) with hard bot-toms; to (b) sheltered bays (Puck Bay and Pärnu Bay) with partiallysoft sediment; and (c) a lagoon (Curonian Lagoon).

Puck Bay is a sheltered coast with an area of 359 km2 and formsa semi-closed part of the Gulf of Gdansk. It is a shallow bay, in par-ticular in its inner part with a maximum depth of 8.5 m. Salinityranges from 5.0 to 7.2 PSU (Pelczarski, 1999). The runoff fromthe Reda river (annual runoff of 0.25 km3) and from the sewagesewer of the Mechelinki village are the main sources of nutrients

Puck Bay

Curonian Lagoon

Lithuanian coast

Fig. 1. South-eastern Baltic Sea with location of the investigated areas – from south to n

(Korzeniewski, 1993). Bottom sediments are mainly sandy, and insome parts covered by seagrasses (Zostera marina) and annualmacrophytes (Pilayella sp.) (Kruk-Dowgiałło, 1991). Puck Bay isalso the marine area of the Nadmorski Landscape Park, a desig-nated HELCOM Baltic Sea Protected Area.

The Curonian Lagoon is a shallow lagoon with an area of1584 km2 and an average depth of 3.5 m, and is connected to theBaltic Proper through the narrow Klaipeda Strait. It is a hypertro-phic freshwater transition zone with high turbidity, largely influ-enced by the Nemunas River. The southern part of the lagoon isfreshwater, while the salinity in the northern ranges between 0and 7 PSU, depending on the water inflow from the open BalticSea. For this study, we focused only on the central part of thelagoon, i.e. outside the reed belts that stretch along its easternshore. Bottom sediments are mainly sandy with large areas ofmuddy bottoms in the southern part. There is only a sparse macro-phyte cover at depths <0.9 m due to high turbidity caused by thehigh primary production and sediment resuspension (Jokšaset al., 1998).

The Lithuanian coast is located to the north of the KlaipedaStrait, with an area of 7000 km2 with exposed areas with highwave energy. Hydrographic conditions are determined by the

Gulf of Riga coast

Pärnu Bay

orth: Puck Bay, Curonian Lagoon, Lithuanian coast, Gulf of Riga coast and Pärnu Bay.

M.T. Tomczak et al. / Progress in Oceanography 81 (2009) 111–131 113

interplay of the south-eastern Baltic offshore waters and the nutri-ent rich freshwater runoff of the Curonian Lagoon (Jokšas, 1994).Salinity ranges from 6 to 8 PSU. The Lithuanian coast is mainly cov-ered by sandy bottoms, but partly also by hard (pebbles, cobblesand boulders) and mixed (sand, gravel, stones) sediments (Oleninet al., 1996). The hard bottoms till 14 m depth are covered by mac-rophytes with the dominant red algae Furcellaria lumbricalis(Labanauskas, 2000).

The Gulf of Riga coast is located between Ainiazi and Dzen�i,Latvia, in the North-Eastern part of the Gulf of Riga, and coversan area of about 240 km2. Within the sheltered Gulf of Riga thearea is one of the most exposed coastal stretches with relativelyhigh wave energy (Eberhard, 2004). The study area is delineatedby the 10 m isobath and the average depth is about 5 m. The Gulfof Riga is a eutrophic area (Wasmund et al., 2001). Salinity rangesfrom 4.5 to 5.7 PSU (monitoring data, Latvian Institute of AquaticEcology). Bottom types range from soft bottoms to rocks and sus-tain high macrophyte biomass. The high biological diversityfavours fish spawning and nursery grounds as well as significantbird feeding. The area is nominated as a HELCOM Baltic SeaProtected area, and it constitutes the marine part of the North Vid-zeme Biosphere reserve.

Pärnu Bay is a shallow semi-enclosed basin in the NE Gulf of Riga,with a surface area of about 700 km2. Its maximum depth increasesgradually from 7.5 m in its inner part to 23 m. A complex interplay ofmeteorological processes, river discharge, and water exchange withthe open part of the Gulf of Riga determines the hydrological condi-tions in the bay. Salinity ranges from 0.5 to 7 PSU with an average at5.5 PSU. The Pärnu River (annual runoff approximately 2 km3)together with the Pärnu town, are the major nutrient sources ofthe bay. Coastline morphology is relatively simple with sandy andsilty sand bottom sediments. Macrophytes occur along the coast,where the water depth is less than 2 m (Kotta et al., 2008).

2.2. ECOPATH approach

Trophic networks of the five coastal ecosystems were comparedusing the ECOPATH with ECOSIM (EwE) software (ver. 4.0 andupdated 5.0; Christensen et al., 2004; Christensen and Pauly,

Phytoplankton Annualmacrophytes

Mesozooplank-ton

Macrozooplank-ton

Planktivorous fish

Fig. 2. Food-web structure o

1992). EwE is a tool to analyze matter and energy flows within asteady-state (ECOPATH) and/or dynamic (ECOSIM) mass balancemodel. Originally proposed by Polovina (1984), the ECOPATH mod-el has been combined with routines for network analysis based onthe approach developed by Ulanowicz (1986).

ECOPATH’s basic equation represents a mass balance for eachtrophic group i in a system of n trophic groups,

BiPi

BiEEi �

Xn

j¼1

BjQ j

BjDCji � EXi ¼ 0

where Bi is the biomass of group i; Pi is its total production; DCji is theproportion of trophic group j in the diet of group i – is a diet matrixcoefficient that describes the trophic relationship between groups;Qi is the total food consumption of group i; the production/biomassratio Pi/Bi and the consumption/biomass ratio Qi/Bi are metabolicrates that express the productivity and consumption per unit of bio-mass, respectively. EEi is the Ecotrophic efficiency, which is the frac-tion of production of group i that is utilized – i.e. consumed, exportedor harvested – within the system. EXi is the net export.

The ECOPATH models for each coastal area share the same 12functional groups for reasons of comparability, but with site-specificspecies composition, aggregated in the functional model groups(Fig. 2). Phytoplankton was represented by a single functional group,while benthic primary producers were divided into annual andperennial macrophytes. Pelagic zooplankton was divided into meso-zooplankton and macrozooplankton. Benthos was represented bybenthic deposit feeders and benthic filter feeders. Three functionalgroups of fish were included – planktivorous, benthivorous (includ-ing also omnivorous species), and piscivorous fish. Birds wereincluded as a single functional group including species with differentsite-specific diet compositions (see Appendix, Tables A.6–A.10). Thehuman impact was indicated by using single fishing fleet. Seals oc-curred only infrequently in the investigated coastal systems andwere, therefore, omitted (Table 2). Data for models derived fromarea-specific research and literature and were collected during aBaltic Sea Regional Project workshop (Anon., 2004).

The input parameters P/B, Q/B and B(Table 1) and the site-specificdiet composition were estimated by using data derived from originalinvestigations and literature (see Appendix, Tables A.1-A.5).

Perennialmacrophytes

Detritus

Benthivorous fish

Birds

Piscivorous fish

Benthicsuspensionfeeders

Benthicdepositfeeders

f the ECOPATH models.

Table 1Input parameters (B – biomass in g C m�2; P/B – production to biomass ratio annual average; Q/B – consumption to biomass ratio annual average; input data after model balance)(Anon., 2004).

Puck Bay Curonian Lagoon Lithuanian coast Gulf of Riga coast Pärnu Bay

B P/B Q/B B P/B Q/B B P/B Q/B B P/B Q/B B P/B Q/B

Birds 0.2 5 14 0.0344 0.3 14 0.0137 0.5 5 0.0015 5 14 0.185 7.027 14.41Piscivorous fish 0.1 0.652 5.3 0.419 0.76 2.71 0.16 0.98 2 0.5 0.819 4.09 1.638 1.198 5.99Planktivorous fish 1.78 0.9 12.9 0.014 0.7 10.13 0.8 0.7 2 1.6 1.12 5.6 2.718 1.12 5.6Benthivorous fish 1.7 0.9 8.9 1.777 0.7 3 0.141 0.7 4 0.6 0.65 8.2 1.198 2.7 13.6Benthic deposit feeders 13.2 0.99 3.4 0.773 8.18 36.77 7.87 1.62 8.12 1.5 0.55 12 13.6 2.8 12.4Benthic suspension feeders 46 0.395 2.212 10.44 0.27 10 95.53 0.88 4.41 3 0.9 13 1.7 0.4 13Macrozooplankton 0.3 4 20 0.0226 8 14.5 0.029 3.1 15 0.45 7.5 25 0.32 8.584 25Mesozooplankton 0.5 75 231.498 0.45 37.8 237.6 0.34 40 160 0.35 45 160 0.3 90 300Perennial macrophytes 49.5 12 n.r 0 0 n.r 9 11.9 n.r 119 3.033 n.r 3 1.2 n.rAnnual macrophytes 243 10 n.r 3.179 12 n.r 1 10 n.r 38 37.7 n.r 0.6 2 n.rPhytoplankton 5.4 36.667 n.r 7.7 196.43 n.r 1.97 190 n.r 1.78 70 n.r 2.4 65 n.rDetritus 14 n.r n.r 2.585 n.r n.r 300.875 n.r n.r n.r n.r n.r n.r n.r n.r

n.r – not relevant.

Table 2Landings (g C m�1 year�2) (Anon., 2004).

Birds Piscivorous fish Planktivorous fish Benthivorous fish

Puck Bay 0.04 0.02 1.12Curonian Lagoon 0.0312 0.262Lithuanian coast 0.07 0.18 0.004Gulf of Riga coast 0.00006 0.024 0.94 0.019Pärnu Bay 0.049 0.930


The Ecotrophic Efficiency (EE) was estimated for all functionalgroups in the models.

2.3. Trophic level decomposition and flows between trophic levels(structural analysis)

Flows of matter between functional groups can be assignedaccording to the discrete trophic level (discrete trophic level, TL,three for example TL III, for further information see Ulanowicz,1995; Christensen et al., 2004) to construct a linearized food chain,i.e. the Lindeman spine (Lindeman, 1942). Transfer efficienciesbetween discrete trophic levels were calculated, and the methodfurther allows comparing ‘‘spines” from different ecosystems(Baird and Ulanowicz, 1993).

The fractional trophic level (arabic numbers e.g. TL 3.5) of con-sumer groups was calculated as the weighted average of the tro-phic levels of their prey, using the consumption of each preyitem as a weighting factor (Christensen et al., 2004). The fractionalTL can be formulated as following:

TLj ¼ 1þXn

i¼1

DCjiTLi

where j is the predator of prey i, DCji the fraction of prey i in the dietof predator j and TLi is the trophic level of prey i.

2.4. Ecosystem properties and trophic network analysis

Eleven of commonly-used ecological indices and ecosystemdescriptors were calculated in the network analysis (Ulanowicz,1986; Baird and Ulanowicz, 1993) routine in ECOPATH for compar-ing ecosystem properties based on maturity attributes, proposedby Odum (1971):

(a) The total system throughput (TST) is defined as the sum ofall flows in a particular ecosystem. It represents the ‘‘sizeof the entire system in terms of flow” (Ulanowicz, 1986).

(b) The ratio between total primary productivity and total sys-tem respiration (TPP/TR) was proposed by Odum (1971),indicating maturity of an ecosystem. Ratios close to 1 indi-cate mature ecosystems.

(c) The net system production (PP–TR), which has to be close to0 in truly balanced (mature) ecosystems.

(d) The total primary production per total biomass (TPP/TB).This has also been used to indicate system maturity(Odum, 1971; Christensen, 1995). Ecosystems in a ‘‘devel-opmental phase” have relatively high TPP/TB ratios, while‘‘mature” systems tend to have lower TPP/TB ratios, asso-ciated with high biomass or low production rate (Christen-sen, 1995).

(e) The system omnivory index (SOI), which characterizes thediversity of consumer–prey relationships (Pauly et al.,1993a,b).

(f) The connectance index (CI) for a given food-web, which is theratio of the number of actual links between functional groupsto the number of theoretically possible links. Feeding on detri-tus by detritivores is included in this index, but the opposite,i.e. detritus ‘feeding’ on other groups is disregarded. Thisindex is also related to the maturity of the ecosystem as duringthe maturity development the food chain structure changesfrom linear to web-like (Odum, 1969, 1971).

(g) The gross efficiency (GE) of the system, which was estimatedas the catch per unit of net primary production (Christensenet al., 2004). The GE tends to be very low, with a global aver-age of 0.0002, in systems with a fishery concentrated on toppredators (Christensen et al., 2004).

(h) The Finn’s cycling index (FCI, Finn (1976)). FCI is the propor-tion of the total system throughput (TST) recycled in the sys-tem. According to Monaco and Ulanowicz (1997), cycling isconsidered to be an important indicator of an ecosystem’sability to maintain its structure and integrity through posi-tive feedback and can though be used as an indicator ofstress (Ulanowicz, 1986) and system maturity (Christensen,1995; Vasconcellos et al., 1997).


(i) The predatory cycling index (PCI), which is a slightly modi-fied FCI. PCI is calculated by excluding the cycling throughdetritus. Disturbed systems are characterized by short andfast cycles while complex trophic structures have long andslow recycling of matter (Odum, 1969; Kay et al., 1989;Christensen, 1995).

(j) Finn’s mean path length, which accounts for the number offunctional groups involved in a flow of matter (Finn, 1976).

(k) Finn’s straight-through path length (excluding detritus),which is another indicator of ecosystem health where a lowvalue indicates a stressed ecosystem with a short food chain.

(l) The ecosystem status indices (Ulanowicz, 1986): ascendancy(A), overhead (O), mutual information (I) relative ascendancy(A/C). A is a measure of system growth (i.e. age, size) anddevelopment (i.e. organization) of network links within theecosystem. A is a function of TST and I :

A ¼ TST� I

where TST is the Total System Throughput and I is the Infor-mation measured in flowbits, based on information theory(see Ulanowicz, 1986). I represents the development and in-crease of system organization (Christensen, 1995). The frac-tion of a system’s capacity is considered as O, which is theenergy in reserve (Monaco and Ulanowicz, 1997). This is ofparticular importance for perturbations (Ulanowicz, 1986).A/C is the fraction of a potential food-web organization thatis actually realized (Ulanowicz, 1986) and it is negatively re-lated to maturity (Christensen, 1995).

(m) The primary production and detritus flows from TL 1, whichare required to sustain fisheries (PPR; expressed asg C m�2 year�1). This allows the evaluation and comparisonof fishing activities across ecosystems. The PPR is obtainedby calculating the flows backwards, expressed in primaryproduction and detritus equivalents, for all pathways fromthe caught species down to the primary producers and detri-tus (Pauly and Christensen, 1995; Christensen and Walters,2004; Coll et al., 2006). The PPR increases with fishing inten-sity and can be formulated as:

PPR ¼Xpaths

Yi

Pi�Y

j;i

Q j

Pj � EEj� DCj;i

" #

where Yi is the catch of a given group i, P the production ofpredator j, Q the consumption of predator j, DC the diet com-position of each predator j/prey i interaction in each path andEE is the ecotrophic efficiency, or the proportion of the pro-duction that it is used within the system due to consumptionor is exported from the system (e.g. in terms of catches). This

Table 3Estimated ecotrophic efficiency (EE).

Puck Bay Curonian Lagoon

Birds 0.002 0Piscivorous fish 0.747 0.75Planktivorous fish 0.335 0.239Benthivorous fish 0.87 0.913Benthic deposit feeders 0.877 0.508Benthic suspension feeders 0.327 0.236Macrozooplankton 0.727 0.493Mesozooplankton 0.81 0.647Perennial macrophytes 0.011 0Annual macrophytes 0.016 0Phytoplankton 0.845 0.062Detritus 0.854 0.039

index can also be expressed relative to the primary produc-tion and detritus of the ecosystem (%PPR) and is related toecological food-print of fishing concept (Folke et al., 1998).

2.5. Mixed trophic impact

The mixed trophic impact (MTI) routine (Majkowski, 1982) inEwE was used to evaluate critical trophic interactions betweenfunctional groups in the ecosystems. Leontief (1951) originallydeveloped this method to assess direct and indirect interactionsin the economy of the USA. A routine similar to Leontief (1951)has been introduced into ECOPATH (Christensen and Pauly, 1992)to study the interaction of direct and indirect effects of functionalgroups (see also Hannon, 1973; Hannon and Joiros, 1989;Ulanowicz and Puccia, 1990).

3. Results

3.1. Observations and food-web description

All the models were balanced. Basic parameterization results forthe five models are shown in Tables 1 and 3, whereas the diet com-position matrices are displayed in the Appendix (Tables A.6-A.10).

The highest total cumulative biomass (excluding detritus) wasfound for the Puck Bay, and it was more than 10 times higher com-pared to the other coastal areas (Table 4). Total cumulative bio-mass of the remaining study areas ranged between14 g C m�2 year�1 and 27.7 g C m�2 year�1.

The pelagic standing stocks, i.e. the cumulative biomass of phy-toplankton, mesozooplankton, and macrozooplankton, were simi-lar in all areas (Table 1). In contrast, the total biomass ofmacrophytes, benthic macrofauna, fish and birds showed large dif-ferences between the areas (Table 1). In almost all systems, but inparticular Puck Bay and Gulf of Riga, the littoral zones were cov-ered by dense macrophyte beds, except for the shallow, turbidCuronian Lagoon. Therefore, macrophytes dominated the primaryproducer biomass (Table 1). In all coastal areas, the biomass of ben-thic fauna exceeded the biomass of pelagic consumers. The highestsuspension and deposit feeder biomasses were observed in thePuck Bay and the Lithuanian coast. Planktivores dominated the fishcommunities with the exception of the Curonian Lagoon, with aslightly lower biomass of benthivorous and piscivorous fish. PärnuBay and Puck Bay had large bird communities, dominated largelyby cormorants (Table 1, Appendix – Table A.5) and in the case ofPuck Bay by cormorants and marine ducks (Table 1, Appendix –Table A.1).

In coastal areas with dense macrophyte growth, annual macro-phytes strongly dominated the total primary production (Fig. 3),which for example varied widely from 160 to 3200 g C m�2 year�1

Lithuanian coast Gulf of Riga coast Pärnu Bay

0 0.008 00.589 0.059 10.893 0.982 10.045 0.940 0.9480.015 0.919 0.4780.037 0.827 00.690 0.978 0.9910.172 1.000 0.7540 0.001 0.2110 0.001 0.630.232 0.409 0.6060.192 0.140 0.963

Table 4Summary statistics and network flows indices of the five ecosystems considerate.

Parameter Value

Puck Bay Curonian Lagoon Lithuanian coast Gulf of Riga coast Pärnu Bay

Ecosystem theory indicesSum of all consumption (g C m�2 year�1) 310.729 167.803 156.982 140.196 332.731Sum of all exports (g C m�2 year�1) 13.386 1375.048 281.668 397.209 8.31Sum of all respiratory flows (g C m�2 year�1) 248.213 139.743 113.342 89.842 152.495Sum of all flows into detritus (g C m�2 year�1) 83.586 1430.817 348.294 460.492 195.571Total system throughput (TST, g C m�2 year�1) 656 3113 900 1088 689Sum of all production (g C m�2 year�1) 3296 1542 419 1944 239Mean trophic level of the catch (MTL) 3.02 3.1 3.19 3.15 3.06Gross efficiency (GE, catch/net p.p.) 0.0004 0.0002 0.0007 0.0005 0.0061Calculated total net primary production (g C m�2 year�1) 3222 1516.326 385.02 1918.127 160.8Total primary production/total respiration (TPP/TR) 12.981 10.851 3.397 21.35 1.054Net system production (PP–TR) (g C m�2 year�1) 2973.787 1376.582 271.678 1828.285 8.305Total primary production/total biomass (TPP/TB) 8.908 108.212 18.351 11.501 5.814Total biomass/total throughput (TB/TST) 0.551 0.005 0.023 0.153 0.04Total biomass (excluding detritus) (TB) (g C m�2 year�1) 361.68 14.013 20.981 166.782 27.659Total catches (g C m�2 year�1) 1.18 0.293 0.254 0.983 0.979Connectance Index (CI) 0.24 0.22 0.198 0.182 0.165System Omnivory Index (SOI) 0.092 0.165 0.059 0.109 0.05

Cycling indicesPredatory cycling index (PCI) 0 4.3 0.01 0 0Throughput cycled excluding detritus (g C m�2 year�1) 0 10.83 0.02 0 0Throughput cycled including detritus (g C m�2 year�1) 6.42 18 22.93 13.18 169.8Finn’s cycling index (FCI) 0.98 0.58 2.55 1.21 24.64Finn’s mean path length 2.507 2.055 2.279 2.233 4.285Finn’s straight-through path length (excluding detritus) 1.96 1.721 1.793 1.836 1.941Finn’s straight-through path length (including detritus) 2.483 2.043 2.221 2.206 3.229

Information indicesAscendency (A) (flowbits) 936.6 3678.4 1084.5 1462.7 893Overhead (Ø) (flowbits) 1726.4 1621.4 1531.8 1549 1724.4Capacity (C) (flowbits) 2663 5299.8 2616.2 3011.7 2617.4Informations (I) 1.428 1.181 1.205 1.345 1.296Relative ascendency (A/C) 0.35 0.69 0.41 0.49 0.34

Perennial Macrophytes Annual MacrophytesPhytoplankton

0

500

1000

1500

2000

2500

3000

3500

Puck Bay CuronianLagoon

Gulf of Rigacoast

Pärnu Bay

Tota

l prim

ary

prod

uctio

n (g

C m

-2ye

ar-1

)

Lithuaniancoast

Fig. 3. Estimated primary production in investigation ecosystems.


in Pärnu Bay and Puck Bay, respectively. Extremely high biomassesof annual macrophytes caused very high primary production inPuck Bay. At a low P/B ratio, perennial macrophytes contributedless to the total primary production than annual macrophytes.With the exception of Pärnu Bay and Puck Bay, where macrophyteswere grazed by benthivorous fish (mainly cyprinids), macrophyteproduction was not channelled into the food-webs directly asshown by the very low ecotrophic efficiency (Table 1). Overall,the macrophytes provided a large source of detritus for benthiccommunities.

Primary production of phytoplankton was largest in the hyper-trophic Curonian Lagoon (1500 g C m�2 year�1). Phytoplanktonprimary production for the other ecosystems ranged from370 g C m�2 year�1 in the Lithuanian coast, which is affected bythe outflow of nutrient rich water from the Curonian Lagoon, to125 g C m�2 year�1 in the Gulf of Riga coast (Fig. 3). The low phy-toplankton productivity in Pärnu Bay with 155 g C m�2 year�1

could be due to the high turbidity in the system.The carbon flows to higher trophic levels can be roughly divided

into pelagic fluxes, channelled from phytoplankton to meso- and


macrozooplankton and further to planktivorous fish, and benthicfluxes. Benthic fluxes are based on detritus, which originates fromdecaying phytoplankton and phytobenthic material. Detritus isconsumed by benthic suspension and deposit feeders, which arein turn consumed by benthivorous fish (Fig. 2). The proportion oftotal carbon flows originating from detritus ranged from 25% to60% in Puck Bay and Pärnu Bay, respectively.

The mesozooplankton production was slightly larger in PuckBay and Pärnu Bay than in the other coastal areas. The pelagicflows, from the lower TL to planktivorous fish show a similar pat-tern than planktivorous fish biomass (Fig. 4). High EEs for meso-and macrozooplankton of the studied food-webs, except for theLithuanian coast, indicate that carbon was passed to planktivorousfish close to the maximum efficiency (Table 3).

Following the differences in biomass, benthic secondaryproduction also varied strongly between the coastal areas, from veryhigh production in the Lithuanian coast, intermediate production atPuck Bay and Pärnu Bay to very low production in the CuronianLagoon and the Gulf of Riga coast. Benthic deposit and suspensionfeeders were mainly preyed upon by benthivorous fish and – to alesser degree – by birds. The flow of carbon from the benthic fauna

0

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8

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18


flow

to p

lank

tivor

ous

fish

(g C

m-2

year

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from mesozooplanktonfrom annual macrophytes

Lithuaniacoast

Fig. 4. Food consumption of the main pelagic

02468

101214161820


Lithuancoas

Ann

ual c

arbo

n flo

w (g

C m

-2 y

ear-1

)

deposit feeders - benthivorous fishsuspension feeders - benthivorous fishdeposit feeders - birds

Fig. 5. Carbon flows in the benthic food-we

to higher trophic levels followed the patterns in the benthivorousfish biomass (Fig. 5), with the exception of the Curonian Lagoon. Herethe high biomass of benthivorous fish was also supported by theimport from the very productive shallow areas of the lagoon (Daunysand Olenin, 1999). Both, production by benthic fauna and predationpressure by benthivorous fish determined the EE of benthic suspen-sion and deposit feeders. The EE was lowest at the Lithuanian coastand Pärnu Bay, with high benthic production but low benthivorousfish biomass, while at the Gulf of Riga coast, the low benthic produc-tion caused a high EE (Table 3).

Fish resources in the investigated coastal Baltic areas weredepleted by fisheries and by predation from birds and piscivorousfish (Fig. 6). The lowest catches (in g C m�2 year�1) were found inthe Lithuanian coast and the highest at the Puck Bay. Also, the struc-ture of the catch differed largely between the ecosystems (Table 2).While fisheries focused on benthivorous fish in Puck Bay and theCuronian Lagoon, planktivorous fish were the dominant catch inthe other systems (Table 2). Predation by birds ranged from verylow (0.021 g C m�2 year�1) in the Gulf of Riga coast to high(2.66 g C m�2 year�1) consumption, exceeding the total fish catches,in Pärnu Bay. However, the high bird predation, due to large cormo-

Pärnu Bay0

0.5

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1.5

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2.5

3

plan

ktiv

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s fis

h bi

omas

s (g

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Gulf of Rigacoast

n

secondary consumer – planktivorous fish.

iant

Gulf of Rigacoast

Pärnu Bay0

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Ben

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deposit feeders - piscivorous fishsuspension feeders - birdsbenthivorous fish biomass

b with Benthivorous fish biomass (B).

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Lithuaniancoast

Gulf ofRigacoast

PärnuBay

Carb

on fl

ow (g

C m

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)

Planktivorous fish Benthivorous fish Piscivorous fish

Fig. 6. Fate of fish biomass (stacked bar groups for each ecosystem denote from leftto right catches, consumption by birds, and consumption by piscivorous fish).


rant colonies in Pärnu Bay mainly affected the piscivorous fish(perch) biomass, whereby the fisheries targeted planktivores. Inthe coastal areas with a high piscivorous fish biomass, predationby piscivores constituted a significant loss for planktivorous andbenthivorous fish, in particular in Pärnu Bay, where piscivore preda-tion exceeded the catch of planktivores and bird predation.

The PPR ranged between 14 and 138 g C m�2 year�1 in Puck Bayand Curonian Lagoon, respectively. For the other ecosystems,differences were not so pronounced and ranged between 26 to40 g C m�2 year�1. The percentage of PPR to TPP had the highestvalue for Pärnu Bay (around 8%) and extremely low values forCuronian Lagoon (0.48%). For Puck Bay and Lithuanian coast esti-mated values of PPR/totPP are relatively high (4–7%), opposite toGulf of Riga (Fig. 8). Gross efficiency ranged from 0.0002 in theCuronian Lagoon to 0.0061 in Pärnu Bay (Table 4).

3.2. Trophic level structure and trophic transfers

The Lindeman spine analysis revealed trophic pathways with upto V levels in all models (Fig. 7). Biomasses associated with the high-est trophic levels (TL IV and V) were very low, especially in the PuckBay and Lithuanian coast models. In Puck Bay, the most efficient tro-phic transfer occurred from TL I to TL II with transfer efficiency (TE) of17.5%. In the other coastal areas, the highest TE occurred between TLII and III (TE 17.5–20.7%). The TE decreases largely between the twolast trophic levels (TL IV and V) (Fig. 7). The most efficient ecosystemin terms of the highest TE, calculated as a geometric mean from theTE in TL II–IV, is Pärnu Bay with 16.6%. The lowest value is calculatedfor the Curonian Lagoon, i.e. 7%.

Despite having used the same model structure for all coastalareas, we found different fractional trophic level composition be-tween groups of organism. The first trophic level in all ecosystemswas, by definition, associated with primary producers (phyto-plankton, perennial/annual macrophytes) and detritus. The secondTL (TL II) was comprised mainly of benthic consumers and meso-zooplankton. Macrozooplankton typically fed on a mixture ofmesozooplankton (TL II), phytoplankton and detritus (TL I), witheffective trophic levels between 2.22 and 2.68. Planktivorous fishmainly fed on trophic levels (TL III). Only in Puck Bay the effectiveTL was lower (2.76), due to fish feeding on annual macrophytes. Inthe Curonian Lagoon and Pärnu Bay, birds occupied the highest tro-phic level (TL 4.39 and 4.2, respectively), while in Puck Bay birdsfed on second (TL II) and third trophic levels (TL III), with an effec-tive TL of 2.78. Piscivorous fish fed on a combination of trophic lev-els, i.e. TL III and TL IV in all systems.

Catches in all areas influenced mostly TL III, but the mean frac-tional TL of the catch was highest in the Lithuanian coast area andlowest in Puck Bay (Table 4). The EE (Table 3) shows the utilizationof fishes in the different ecosystems. The EE of planktivorous fishwas much higher in the Gulf of Riga coast and Pärnu Bay than inPuck Bay and Curonian Lagoon. Similarly, EE of benthivorous fishhad high values around 1 in all ecosystems, except the Lithuaniancoast. Overall, piscivorous fish had high EE values in most systems(Table 3).

3.3. Ecosystem properties and network analysis results

In general, low values of SOI imply that consumers are special-ized and feed mainly on single trophic levels. The SOI and CI valuewere the lowest in Pärnu Bay (0.05 and 0.165, respectively). More-over in the other ecosystems, SOI increased to the maximum valueof 0.17 in the Curonian Lagoon (Table 4). The highest CI was esti-mated for Puck Bay (0.24).

The TPP/TR ratio, indicating the maturity of an ecosystem, hasbeen calculated for all areas (Table 4). Here, the Pärnu Bay wasthe most mature ecosystem with a TPP/TR near to 1. Values ofTPP/TR for the other ecosystems were far from unity and rangedbetween 3.4 and 21.2. The net system production, indicating thematurity of an ecosystem, was low in Pärnu Bay. For the other eco-systems net system production was very high >271 g C m�2 year�1,indicating a higher developmental stage of the coastal systems. TheTPP/TB ratio showed the same pattern, indicating again that PärnuBay was the most mature ecosystem.

The estimated FCI value (Table 4) in Pärnu Bay (24.6%) wasmuch higher than in the other ecosystems, where the FCI rangedfrom 2.5% to 0.58% (Table 4). This again indicates that Pärnu Bayis the most mature and pristine ecosystem, where the highestproportion of energy is recycled. A high Finn’s straight-throughpath length in Pärnu Bay and Puck Bay also suggests a relativelyhigh system maturity. The predatory cycling index (PCI) wasclose to zero for almost all ecosystems except Curonian Lagoon(Table 4). This indicates that secondary production of the systemis mainly based on detritus, suggesting that all net primary pro-duction is not directly used and enters the food-web throughheterotrophic benthic organisms. In the Curonian Lagoon the rel-atively high PCI (4.3%) suggests the importance of predation inthe structure and functioning of the ecosystem at higher trophiclevels.

Using macro descriptors, as A and A/C, the Curonian Lagoonappeared to be the most mature ecosystem, where the high A(3678 flowbits, Table 4) was compensated by a low value of I (1.81flowbits). The other ecosystems ranged between 893 and 1084 flow-bits (Table 4). Moreover, in almost all ecosystems, except theCuronian Lagoon, I had the same pattern like A (Table 4). The calcu-lation of A and A/C for all ecosystems indicates that the most maturesystems were the Gulf of Riga coast and the Lithuanian coast. Thehighest O was calculated for Pärnu Bay and Puck Bay. The O for theother study areas ranged between 1726 and 1531 flowbits.

3.4. Mixed trophic impact analysis

The MTI for all areas indicates that the benthic primary produc-ers did not or very little affect the other functional groups. The onlyexception here was Puck Bay, where annual macrophytes had apositive influence on higher trophic levels, supporting birds, bent-hivorous fish community and benthic deposit feeders. In the Gulfof Riga, annual macrophytes affected the benthivorous fish bio-mass and. thereby, influenced the benthic fauna and birds. Birdswere also affected in the Curonian Lagoon and Pärnu Bay, and toa lesser degree in Puck Bay. In the Curonian Lagoon and Pärnu

TLTE%

Export

Resp.

Consum.

Flow to detr

TLTE%

Export

Resp.

Consum.

Flow to detr

TLTE%

Export

Resp.

Consum.

Flow to detr

VVIIIIIII

D

1.8 20.3 12.1 0

111 1.44 0.18 0.0

0.0 0.21 0.44 0.0

35.17 0.15 0.010.0

VVIIIIIII

D

0

1.44 0.18 0.0

0.00.0

66.8298281

Lithuanian coast

VVIIIIIII

D

0

111 1.44 0.18 0.0

0.00.0

0.0

2.83

10.0

VVIIIIIII

D

0

1.44 0.18 0.0

0.00.0

298

0.073.08.68VVIIIIIII

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111 1.44 0.18 0.0

0.00.0

35.17 0.010.0

VVIIIIIII

D

0

1.44 0.18 0.0

0.00.0

298

VVIIIIIII

D

0

111 1.44 0.18 0.0

0.00.0

0.91 0.010.0

VVIIIIIII

D

0

1.44 0.18 0.0

0.00.0

298

VVIIIIIII

D

17.4 17.5 10.7 1.2

0.150.82 00.010.0

75.6 12.5 1.67 0.0820.99 4.34 0.76 0.05

20.4VVIIIIIII

D

1.21.2

0.08434 64.26

396

52.6

Gulf of Riga coast

VVIIIIIII

D

1.2

0.08

VVIIIIIII

D

1.21.2

0.08

2.8 0.139VVIIIIIII

D

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0.15 200.010.0

0.080.76 0.05

VVIIIIIII

D

1.21.2

0.08

VVIIIIIII

D

1.2

0.08

VVIIIIIII

D

1.21.2

0.08

2.8 0.139

0.73

VVIIIIIII

D

14 20.7 15.7 1

0.0 0.92 0.05 0.0

118 29 4 0.36125 2.3

13.79.93VVIIIIIII

D

14 20.7 15.7 1

0.0 0.92

7.55

0.0

63.04811

64.7 2.1

96.1 13.7

Parnu Bay

0.73

VVIIIIIII

D

14 20.7 15.7 1

0.0 0.92 0.05 0.0

118 29 4 0.36125 2.3

13.79.93VVIIIIIII

D

14 20.7 15.7 1

0.0 0.92

7.55

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118

188.2

4 0.36

64.7 2.1

96.1 13.7

VVIIIIIII

D

2.5 20.6 6.6 0.2

0.0 0.27 0.03 0.0

3.22 0.92 0.05

56.0 1.29 0.26 0.0

VVIIIIIII

D

2.5 20.6 6.6 0.2

134 3.22 0.92 0.051419

Curonian Lagoon

10.71376

VVIIIIIII

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2.5 20.6 6.6 0.2

3.22 0.92 0.051.29 0.26 0.0

3.76VVIIIIIII

D

2.5 20.6 6.6 0.2

134 3.22 0.92 0.051419

0.060.9093.5

Curonian Lagoon

VVIIIIIII

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2.5 20.6 6.6 0.2

0.0 0.27 0.03 0.0

3.22 0.92 0.051.29 0.26 0.0

VVIIIIIII

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2.5 20.6 6.6 0.2

134 3.22 0.92 0.051419

Curonian Lagoon

VVIIIIIII

D

2.5 20.6 6.6 0.2

3.22 0.92 0.051.29 0.26 0.0

3.76VVIIIIIII

D

2.5 20.6 6.6 0.2

134 3.22 0.92 0.051419

0.060.9093.5

Curonian Lagoon

VVIIIIIII

D

0.42.63.55.71

0.05 1.06 0.07 0.0

206 40. 9 1.14 0.01

9.65 2.19 0.01

46.6 7 VVIIIIIII

D

0.42.63.55.71

1.14 0.01

71.3

Puck Bay

0.001

192

71.6

VVIIIIIII

D

0.42.63.55.71

206 40. 9 1.14 0.01

800.0533.1 VVIIIIIII

D

0.42.63.55.71

1.14 0.01

Puck Bay

0.00171.6

VVIIIIIII

D

0.42.63.55.71

206 40. 9 1.14 0.01

9.65 2.19 0.01

12.76

46.6 7 VVIIIIIII

D

0.42.63.55.71

1.14 0.01

Puck Bay

0.001

192

71.6

VVIIIIIII

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0.42.63.55.71

206 40. 9 1.14 0.01

800.0533.1 VVIIIIIII

D

0.42.63.55.71

1.14 0.01

Puck Bay

0.00171.6

Fig. 7. The aggregation of the flow (g C/m�2/year�1) web into a concentrated chain through five trophic levels (Ulanowicz, 1995) (roman numbers inside boxes – TL,Arabic - TE%-Transfer Efficiencies in %).


Bay, birds had a relatively high direct impact on fish stocks and anindirect effect on benthic invertebrates (Fig. 8), whereby in PuckBay birds affected mostly benthic fauna.

In all models, fisheries impacted almost all other ecosystemcomponents through trophic cascades. In the Gulf of Riga, wefound a surprisingly large fisheries impact on birds, caused bythe removal of piscivorous fish, indirectly increasing the competi-tion of benthivorous fish for benthic filter feeders, the main preyfor the birds in this area.

4. Discussion

Our model results represent five eastern Baltic Coastal food-webs, which have been analyzed using the same ECOPATH modelstructure. As Baird and Ulanowicz (1993) pointed out, a similarmodel structure is crucial to compare different ecosystem models.However, species aggregated into the functional model groups dif-fered largely between ecosystems, especially with respect to fishcommunities. Further, a unified model structure also simplifies

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Lithuaniancoast

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PPR

(gC

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PPR

/Tot

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)

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Fig. 8. Primary Production Required (PPR) and %PPR from Total Primary production to sustain catches.


the comparison of food-web interactions in different ecosystems.Species lumping and aggregation into functional groups mightaffect model results (Abarca-Arenas and Ulanowicz, 2002), inparticular with respect to calculated indices.

According to Okey and Pauly (1999), ecosystem-based models,like ECOPATH, integrate previously disparate ecosystem informa-tion. This approach was also used in this study to present and com-pare the entire ecosystem structure and function of theinvestigated ecosystems. ECOPATH model construction allows usto gain a better understanding of individual resource componentsand their potential trajectories in an ecosystem structure and func-tion (Okey and Pauly, 1999).

The quality of the ECOPATH models depends on the underlyinginput data. Our team of authors consists of researchers at localinstitutes who are each familiar with a particular study site. Theircommunications with national experts further helped to identifykey ecosystem components and relevant data sources, includinga large number of site-specific publications and reports in localjournals and languages (see Appendix Tables A.1-A.5). In particular,the biomass information used in this study was almost exclusivelytaken from local research surveys and national monitoring pro-grams. Similarly, most of the diet composition was derived fromlocal research publications and expert knowledge (see AppendixTables A.6-A.10). However, the time-period covered by the datasources differs somewhat between species and ecosystems.Although most of the biomass data describe the 1990s and thetime-period until 2005, we cannot exclude that temporal changesin the ecosystems overlap differences between the systems stud-ied. Local studies were not always available to define P/B and Q/Bcoefficients. In this case, coefficients used in previous Baltic models(Harvey et al., 2003; Sandberg et al., 2000) or values published forneighbouring areas were applied.

Due to the lack of data, the microbial loop was omitted in themodels. As pointed out by Witek (1995), bacteria and protozoo-plankton contribute the largest energy flow among heterotrophicorganisms in the coastal pelagic zone. However, carbon transferefficiencies from the microbial loop to the ‘‘classical” food-webcan be low (Uitto, 1996). As our models are focused on carbonfluxes to the higher trophic levels, we omitted bacteria and treatedthe microbial loop as part of the carbon flows originating fromdetritus.

Morphometry, determining water exchange and sedimentation,influences the trophic state of coastal ecosystems together withlocal nutrient sources (Wallin and Hakanson, 1992; Nilsson and

Jansson, 2002). By far the largest phytoplankton primary produc-tion was observed in the Curonian Lagoon. The lagoon is affectedby loading from the Nemunas River and has limited waterexchange with the Baltic Proper. Also in the sheltered Puck Bay,phytoplankton primary production is high, because of loadingsfrom the Reda and Vistula rivers in addition to nutrient runoff fromagriculture and atmospheric deposition (Korzeniewski, 1993;Falkowska and Bolałek, 1991). Similarly, the sheltered Pärnu Bayis also affected by the loading of the Pärnu River and has a highphytoplankton primary production.

Occurrence of macrophytes was restricted to sites with suffi-cient light and suitable substrate for growth. Thus, in the Lithua-nian coast only 1% of the area was covered by macrophytes,while in the Gulf of Riga coast dense macrophyte stands coveredboulders at 5–8 m depth. Contrary to the Lithuanian coast, the Gulfof Riga coast and Pärnu Bay, where the perennial macroalgae Fucussp. and Furcellaria sp. constitute the perennial macrophyte group,the seagrasses Zostera sp. and Zannichellia sp. are found in PuckBay. The very high biomass used in the model for the annual mac-rophyte Pilayella sp. in Puck Bay may be overestimated, becausedata were derived from a pilot study with a small number of obser-vations (Kuczynski, personal information).

The biomass of benthic consumers generally differed morebetween the studied coastal areas than the biomass of pelagicconsumers. This is also due to the fact that many benthic specieshave a lifespan of several years and, therefore, differences ingrowth conditions become accentuated over a longer time-period.In contrast, phytoplankton and zooplankton have turnover timesfrom days to months. The difference in the benthic invertebrateassemblages may be partly attributed to the type of bottomsubstrate and the intensity of water exchange. For example, PärnuBay is characterized by high riverine nutrient input, relatively lowwater exchange and, thus, a high sedimentation rate. Conse-quently, organic rich soft sediments support the very high densi-ties of deposit feeders, whereas the suspension feeders are onlypresent in low numbers. In the other coastal areas, the biomassof suspension feeders exceeds that of the deposit feeders. In moresaline areas, the communities of suspension feeders are domi-nated by Mytilus trossulus, whereas in more fresh-water areas,such as in Curonian Lagoon and Pärnu Bay, Dreissena polymorphaprevails.

Different hydrological conditions also lead to different speciescompositions in the fish groups that were in turn modified byfishing pressure. Despite freshwater species dominating the fish


communities in Pärnu Bay, herring also occurred in the bay be-cause of potential (Kornilovs, 1994; Kotta et al., 2008) suitablespawning grounds and high abundance of the Gulf of Riga her-ring stock. In contrast, the central Curonian Lagoon with verylow salinity (or almost fresh water) is unfavourable for herring(Ozdeep, 1988) and low perennial macrophyte biomass providesunfavourable conditions for fish species that prefer vegetatedbottoms for spawning. The low biomass of herring in Puck Baymay be due to the reduction of macrophyte coverage causedby eutrophication-induced destruction of spawning grounds(Jackowski, 1998; Andrulewicz et al., 2004). Alternatively, a veryhigh biomass of three-spined stickleback (Sapota and Skóra,1996; Lizinska, 2002) might have caused competition betweenfish in the basin. Three-spined stickleback feed on eggs of com-mercially important species (Andrulewicz et al., 2004), especiallyin the very shallow part of the bay, where the herring spawninggrounds were formerly located.

In contrast to phytoplankton primary production, phyto-benthos production is not channelled directly into the investi-gated food-webs, as indicated by the low ecotrophic efficiency(EE) of macrophytes. Further, the mixed trophic impact (MIT)matrix indicated a very low dependency of higher trophic levelson benthic macrophytes, suggesting that changes in benthic pri-mary production do not affect the trophic web directly. This is incontrast to other ecosystems (Carrer and Optiz, 1999). Whileperennial macroalgae are grazed on a very low level in manymarine systems (Duarte, 1995; Worm et al., 2000; Szyrmer andUlanowicz, 1987), including the Baltic Sea (Kautsky, 1988;Kautsky, 1995), annual macrophytes are a potential food sourceto benthic grazers (Duarte, 1995; Worm et al., 2000) and benthi-vorous fish. Macrophytes consumed by benthivorous fish are adirect food source to the food-web of Pärnu Bay, where annualmacrophytes are partially utilized (Kotta et al., 2006a,b). Also,the very high biomass of annual macrophytes in Puck Bay, espe-cially the drifting form of Pilayella sp. (Florczyk in Korzeniewski,1993; Paalme et al., 2002), are consumed directly and were ex-ploitable at the higher trophic levels. In general, the treatment ofmacrophytes in the food-web models might thus have been lim-ited to studies available on the investigated sites.

Overall, the low trophic transfer of macrophyte carbon intothe food-web (Table 3) does not correctly reflect the signifi-cance of macrophytes for the Baltic ecosystem. Our findingssuggest that benthic macrophytes are an important detritussource for the food-web. Benthic macrophytes are also an im-portant habitat forming species, providing shelter for benthicanimals (Kautsky, 1988; Kruk-Dowgiałło, 2000; Martin, 2000;Orav-Kotta and Kotta, 2004), as well as spawning and nurseryareas for fish (Kruk-Dowgiałło, 2000; Jackowski, 1998; Skórain Korzeniewski, 1993).

The investigated ecosystems differed in their trophic composi-tion, especially for fish and birds. The number of five discretetrophic levels sensu Lindeman (Ulanowicz, 1995) is commonlyfound in marine costal ecosystems (Christensen and Pauly,1993) (Fig. 7). However, the assignment of groups to a specifictrophic level is sensitive to the assumed diet composition. Forexample, the effective fractional trophic level of piscivorous fishranges from 3.55 to 3.91 for the Curonian Lagoon and the twoGulf of Riga systems, even though they include the same species(perch and pike perch) in this functional group. Other differ-ences, such as the low effective trophic level of birds in PuckBay can easily be linked to high consumption of benthic organ-isms by the marine ducks (Stempniewicz and Meissner, 1999)in Puck Bay. The dependence of birds on the benthic organismsin Puck Bay is also visible in the MTI analysis (Fig 9). In contrast,cormorants dominate the bird biomass in the Curonian Lagoonand in Pärnu Bay (Appendix – Tables A.1 and A.5), where they

act as top predators, consuming different fish species, includingalso piscivores (Fig. 6).

As indicated by the varying level of EE, phytoplankton primaryproduction is channelled into food-webs with highly differentefficiency (Table 3). In the Curonian Lagoon, phytoplankton is dom-inated by the filamentous cyanobacteria Aphanizomenon flos-aquae,and despite the large phytoplankton primary production, theamount of carbon transferred to zooplankton is relatively low.The low efficiency is also reflected in the transfer efficiencies calcu-lated in the Lindeman spine (Fig. 7). The reason might be that thedominating cyanobacteria are not grazed efficiently (Razinkovasand Gasi�unaite, 1999), and the high predation within the zooplank-ton community, with high biomasses of Leptodora kindtii which canconsume Daphnia sp. and other species (Pliuraite, 2001; Chang andHanazato, 2004). The most complete phytoplankton–zooplanktontransfer, and thus highest EE of phytoplankton, occurs in the PuckBay, probably because of the high zooplankton biomass in the shel-tered bay. In addition, the EE of phytoplankton is also high in thePärnu Bay, probably because of the high Q/B ratio of the dominat-ing small-sized zooplankton.

The benthic systems in all investigated sites are mainly con-trolled by detritus availability, suitability of the bottom substrateand predation. The carbon fluxes in all studied benthic food-websshow a similar carbon flow pattern. The only exception is theCuronian Lagoon where the carbon fluxes are different (see Section4 above). This suggests that the amount of energy available for sec-ondary production is mainly derived from the detritus. In shelteredecosystems like Puck Bay and Pärnu Bay, primary production isretained, while exposed systems like the Lithuanian coast and theGulf of Riga coasts tend to export their primary production to theadjacent open water areas, which were not included in the model.

The role of primary production for benthic consumers is alsoillustrated by the MTI matrix, i.e. phytoplankton enhances benthicproduction. However, since benthic fauna is the main food sourceof benthivorous fish in all ecosystems, the MTI matrix also predictsimpacts of benthivorous fish on their prey in all ecosystems. Thedegree of predation control on macrozoobenthos is difficult toassess, because in all ecosystems benthivorous fish are heavilyexploited with ecotrophic efficiencies close to one.

While carbon transfer into pelagic and benthic food-webs isrelated to the retention capacity of coastal ecosystems, mesozoo-plankton is further exploited with a close to maximum EE in allecosystems, except the Lithuanian coast. In Puck Bay, the Gulf ofRiga coast and Pärnu Bay, large fluxes from mesozooplankton tothe pelagic fish occur, while in the Curonian Lagoon the high EEof the mesozooplankton may be caused by L. kindtii predation onDaphnia sp. In Puck Bay and the Curonian Lagoon, hydrologicalconditions are unfavourable for commercially valuable planktivo-rous species and, therefore, planktivorous fish is not exploited fur-ther, resulting in a low EE. The higher trophic level predators, forexample cormorants are trophic opportunists, i.e. selecting preythat can be accessed with the lowest effort (Bzoma, 2004). In theGulf of Riga coast and Pärnu Bay, planktivorous fish are largelyreduced by fishing, predation from piscivores, and in the case ofPärnu Bay also by the predation of birds. However, birds in PärnuBay mainly prey on piscivores. In addition, the MTI matrix suggeststhat planktivorous fish and the fishery even benefit from birdpredation.

Despite high catches of planktivorous fish in the Gulf of Rigacoast ecosystem and Pärnu Bay, the MTI matrix suggests onlyvery small or no impact of fisheries on planktivorous fish. Mostlikely, removal of planktivorous fish is balanced by increasedmesozooplankton production in the Pärnu Bay, reflected also ina stable herring population in the Gulf of Riga (ICES, 2005). Incontrast, the MTI matrix suggests very strong negative impactsof fishing in the Lithuanian coast, where planktivorous fish are

Puck Bay

-1-0.8-0.6-0.4-0.2

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Gulf of Rigacoast

Parnu Bay

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Fig. 9. Mixed trophic impact plot of birds, annual macrophytes and fishery in investigated areas. Note other scale for impact of annual macrophytes in Gulf of Riga coast.


exploited heavily. This high fishing pressure causes further a cas-cading effect to the lower trophic levels. Also in the Puck Bay,effects of fisheries are pronounced (Andrulewicz et al., 2004),with a strong trophic cascade. The wide impact spectrum of fish-ing activities, causing direct and indirect effects on fish popula-tions and the entire ecosystem, has been documented forexample by Pauly et al. (2000).

The lowest gross efficiency (GE) simulated for the CuronianLagoon is not related to the fishing pressure on predatory fish, asbenthivorous fish with a low TL dominate the catch. The low GEis probably more related to the inefficient use of the high primaryproduction. GE is also rather low in the other systems with a highshare of phytobenthos primary production (Puck Bay, Gulf of Riga),because the latter is not channelled into the food-webs. Still almostall systems, except the Curonian Lagoon, had higher GE than theglobal average of 0.0002 (Christensen et al., 2004), calculated fora wide range of marine ecosystems. High GE with a relatively highvalue (>4%) of the PPR/totPP for Puck Bay, Lithuanian coast andPärnu Bay may suggest high fishing impact on the whole ecosys-tem in those areas. Despite similar catches and catch species com-position in Pärnu Bay and the Gulf of Riga coast, the ecological

footprint of fisheries is higher in Pärnu Bay ecosystem, partlybecause of the lower primary productivity of the system. The lesspronounced ecological footprint of fisheries in the Curonian Lagoonand Gulf of Riga coast indicates that fisheries are not affectingthose ecosystems heavily. That could be explained by the highand stable biomass of benthivorous fish in the Curonian Lagoon(Repecka et al., 2002b,a) and herring stock in the Gulf of Riga coast(ICES, 2005).

Our findings suggest that the most efficient (the highest aver-age TE%) ecosystem is the Pärnu Bay. This is because of the highpiscivorous fish and bird predation. The lowest efficiency wassimulated for the Curonian Lagoon (average 7%), probably dueto the inefficient use of primary production (see the discussionabove). In contrast, Puck Bay with a similar low efficiency showsa different pattern. Here, the zooplankton is utilized with a lowEE, leading to a low TE between II and III. In Pärnu Bay, theLithuanian coast and the Gulf of Riga coast, the ecosystems ex-ceed the range of average trophic efficiency (10–15%) for coastalareas (Christensen and Pauly, 1993). This could be due to over-estimation of the herring biomass and catch in the coastal sites,as the data are mostly available for open areas. For example, it is


well known that in ‘‘open” areas like the Lithuanian coast andthe Gulf of Riga, coast, piscivorous and planktivorous fishmigrate between different feeding and spawning areas (Kom-powski, 1994; Jackowski, 2002). Therefore, the estimation offood consumption and catch in the coastal zone remains diffi-cult. Further, a potential overestimated biomass of herring couldalso have exaggerated the differences in the zooplankton–plank-tivorous fish transfer efficiency, causing additional variation be-tween herring dominated systems (Lithuanian coast, Gulf ofRiga coast, Pärnu Bay) and the Curonian Lagoon and Puck Bay,where the dominant planktivorous fish species are ziege (Pelecuscultratus) and three-spined stickleback (Gasterosteus aculeatus).However, there is no doubt about the occurrence of Baltic her-ring in almost all investigated areas, except the Curonian Lagoon.For example, the Gulf of Riga is known to have a separate her-ring population and shoals of clupeids have been reported fromPuck Bay (Jackowski, 2002).

Average transfer efficiencies ‘‘from producers” were lower than‘‘from detritus” in the Curonian Lagoon, showing difficulties inchannelling phytoplankton into the food-web and highlighting

Table A.1Main species and data sources for the Puck Bay ECOPATH model.

Functional group Main species in the group Biomass

Birds Phalacrocorax carbo; Melanittafusca

Meissner (1997), Bzoma (2004

Piscivorous fish Gadus morrhua; Perca fluviatilis;Belone belone; Salmo truttam.trutta

ICES (2000), Kompowski (1994Kruk-Dowgiałło (2000), JackowZaporowski (1995)

Planktivorous fish Gasterosteus aculeatus; Clupeaharengus; Coregonus lavaretus

ICES (2000), Witek (1995), Kru(2000), Sapota and Skóra (199(2002), Zaporowski (1995)

Benthivorous fish Platichthys flesus; Anguillaanguilla; Pomatoschistus minutus/microps; Neogobius melanostomusZoarces viviparus Rutilus rutilus

ICES (2000), Sapota and Skóra(1995), Kruk-Dowgiałło (2000(2002), Korzeniewski (1993), Hand Skóra (1998), Zaporowski

Benthic depositfeeders

Crangon crangon; Hedistediversicolor; Gammarus sp.

Warzocha (1995), KorzeniewsKruk-Dowgiałło (2000)


Mytilus edulis trossulus; Macomabalthica; Cerastoderma glaucum;Mya arenaria

Warzocha (1994, 1995), KorzeKruk-Dowgiałło (2000)

Macrozooplankton Mysis mixta, Neomysis integer Korzeniewski (1993), Kruk-Do

Mesozooplankton Acartia sp.; Temora sp.;Pseudocalanus sp. Cladocerans;Rotatoria

Korzeniewski (1993), Kruk-Do(2000)


Zostera marina Korzeniewski (1993), Kruk-Do1991), Jackowski (1998), Man

Annualmacrophytes

Ectocarpaceae; Pilayella sp.Cladophora sp. Enteromorpha sp.

Korzeniewski (1993), Guestimpreliminary local survey

Phytoplankton Including cyanobacteria Korzeniewski (1993), Kruk-Do1991), Mankowski (1978)

Detritus Including bacteria Pauly et al. (1993)

the importance of secondary production from detritus. In all othersystems transfers from producers were more efficient. In particu-lar, the Gulf of Riga coast with its low zoobenthos biomass, chan-nelled detritus-based flows inefficiently. In Puck Bay transferefficiencies from producers and detritus were almost equal.

The detritus-based food-webs and their poor transfer effi-ciency towards higher trophic levels, associated with a low com-plexity could suggest that the systems are far from a stable,mature ecosystem sensu Odum (Odum 1969; Ulanowicz, 2003;see Lobry et al., 2008). However, most marine systems are char-acterized by a combination of ecological indicators, indicatingboth ecosystems under development and mature ecosystems(Baird et al., 1991; Eliott and Quintino, 2007; Lobry et al.,2008). In particular, this is true for transitional waters, such asestuaries and bays (Monaco and Ulanowicz, 1997; Wilson andParker, 1998; Rybaczyk et al., 2003; Lobry et al., 2008). This isalso the case for south-eastern Baltic coastal ecosystems, espe-cially of the Curonian Lagoon where part of indices (A, A/C,TST, PCI) imply the most mature ecosystem sensu Odum. How-ever, according to Mann et al. (1989), system ascendancy (A)

P/B Q/B Diet matrix information

) Nelson (1979) Bzoma(2004),Stempniewiczand Meissner(1999)

Bzoma (2004),Stempniewicz andMeissner (1999)

), Witek (1995),ski (2002),

ICES (2000),Kompowski(1994), Witek(1995), Hoenig(1983)

Witek (1995),Pauly (1989)

Pauly (1989), Haluch andSkóra (1997), Załachowskiet al. (1975), Jackowski(2002)

k-Dowgiałło6), Lizinska

ICES (2000),Harvey et al.(2003), Witek(1995)


Szypula et al. (1997),Załachowski et al. (1975),Thorman and Wiederholm(1986), Jackowski (2002)

(1996), Witek), , Lizinska

orackiewicz(1995)

ICES (2000),Witek (1995),Hoenig (1983)


Kruk-Dowgiałło (2000),Jackowski (2002), Costaet al. (1992)

ki (1993), Bray (1999) Jarre-Teichman(1995), Witek(1995)

Jarre-Teichman (1995),Witek (1995)

niewski (1993), Bray (1999) Jarre-Teichman(1995), Witek(1995)


wgiałło (2000) Bray (1999) Jarre-Teichman(1995), Witek(1995)


wgiałło Kruk-Dowgiałło(2000),Korzeniewski(1993)

Jarre-Teichman(1995), Witek(1995)


wgiałło (2000,kowski (1978)

Korzeniewski(1993), Kruk-Dowgiałło (2000)

ate based on Korzeniewski(1993), Kruk-Dowgiałło (2000),

wgiałło (2000, Korzeniewski(1993), Kruk-Dowgiałło (2000),Mankowski(1978)

Table A.2Main species and data sources for the Curonian Lagoon ECOPATH model.

Functional group Main species in thegroup

Biomass P/B Q/B Diet matrixinformation

Birds Ardea cinerea;Phalacrocorax carbo

Zarankaite, personal communication, carbonconversion after Jorgensen et al. (1991),McLusky (1981)

Nelson (1979) Calculated from annual fishconsumption by grey herons inLithuania, conversion followingMcLusky (1981), Cohen andGrosslein (1987)

Expert‘‘guestimate”

Piscivorous fish Perca fluviatilis;Stizostedion lucioperca

Adapted from Repecka (1997), Carbonconversion after McLusky (1981), Cohen andGrosslein (1987)

Zaika (1983) Rudzianskiene (1994), Harvey et al.(2003)

Lozys (2002)

Planktivorous fish Gasterosteusaculeatus; Pelecuscultratus; Osmeruseperlanus

Adapted from Repecka (1997) Adapted from Repecka(1997)

Adapted from Repecka (1997) Repecka(1997)

Benthivorous fish Rutilus rutilus;Abramis brama; Bliccabjoerkna;Gymnocephaluscernuus

Adapted from Repecka (1997) Zaika (1983) Zaika (1983) Zaika (1983)


Valvata spp.; Bithyniaspp.; Potamopyrgusspp.; Hydrobia;Chironomidae;Oligochaeta

Coastal Research and Planning Institute,unpublished data, averaged biomassbetween mud, sand and shell depositcommunities, carbon conversion afterKautsky (1995)

Zaika (1983), adaptedto the number of activedays

Monakov (1998), adapted to thenumber of active days, forOligochaeta Witek (1995)

Monakov(1998), forOligochaetaWitek(1995)


Unio spp.; Dreissenapolymorpha

Coastal Research and Planning Institute,unpublished data, carbon conversion afterKautsky (1995)


Monakov (1998) Monakov(1998)

Macrozooplankton Paramysis lacustris;Limnomysis benedeni

Lesutiene, unpublished data, dry weight andcarbon conversion after Rumohr et al. (1987)


Witek (1995) Monakov(1998)

Mesozooplankton Chydorus sphaericus;Daphnia longispina;Bosmina coregoni;Mesocyclops leuckartii

Coastal Research and Planning Institute,unpublished data

V. Christensen,personalcommunication

Sushchenia (1975), Monakov (1998) Sushchenia(1975),Monakov(1998)


Potamogetonperfoliatus


Coastal Research andPlanning Institute,unpublished data

Annualmacrophytes

Ectocarpaceae;Pilayella litoralis;Cladophora sp.;Enteromorpha sp.


Phytoplankton Cyanobacteria andother species

CHARM (EU FP 5) database assuming 3.5 mdepth, 1997–2004

Net primaryproduction/biomassratio from Kavolyte,unpublished data from1999–2001

Detritus Including bacteria Pauly et al. (1993a,b)


and TST as also reflect the eutrophication of an ecosystem and ahigh A, as a function of elevated high TST, in parallel to a lowmutual information (I) (Ulanowicz, 1986) indicate hyper-eutro-phication instead of maturity. The other indices applied(Table 4) clearly indicate the developmental stage of CuronianLagoon.

The analysis of ecosystem characteristics and maturity indi-ces (TE, TPP/TR, TPP/TB, PP–TR, SOI, CI) indicate that the PärnuBay is a mature ecosystem, characterized by the high transferefficiency, the more web-like trophic system, high carbon recy-cling, energy conservation and stability. However, the ascen-dancy of the system does not confirm these findings. Thiscould be caused by the small area of the system or the hydro-logical stress caused by the freshwater inflow of the Pärnu Riv-er. The other investigated ecosystems are in the developmentalstage sensu Odum, which could also be a signal of a ‘‘stressedecosystem” (Eliott and Quintino, 2007). Overall, the analysis ofthe studied ecosystems allowed a ranking of the maturity level,as well as the state of development and stability: Pärnu Bay >Gulf of Riga coast > Lithuanian coast > Puck Bay > CuronianLagoon.

5. Conclusions

The investigated south-eastern Baltic coastal ecosystems arehighly productive and channel a large proportion of their totalprimary production into detritus. Our comparative flow and net-work analysis reveals marginal direct impacts of macrophytes ontrophic transfers in all investigated ecosystems. Further, thisstudy suggests that macrophyte biomass is mainly transformedinto detritus. Because of the low water column primary produc-tivity and the high benthic primary productivity, ecosystems ap-pear to be very dependent on the proportion of the macrophyteproduction that is recycled within the benthic system. The roleof macrophytes in the trophic transfers of the coastal Baltic eco-systems is most likely underestimated in the models. The rea-sons for this need to be investigated more thoroughly in thenear future. However, our modelling efforts show that the per-ception of the role of macrophytes depended largely on dataand availability of information about the particular ecosystems.

In all ecosystems, fisheries had far reaching impacts on theirtarget species and on the food-web in general. In particular, ben-thic food-webs were partly affected by indirect fisheries effects.

Table A.3Main species and data sources for the Lithuanian coast ECOPATH model.

Functional group Main species in the group Biomass P/B Q/B Diet matrixinformation

Birds Clangula hyemalis; Melanitta fusca; Melanitta nigra; Gaviaarctica; Gavia stellata; Polysticta stelleri

Švazas et al. (2001), Zydelis(2001)

Nelson(1979)

Expertknowledge

Zydelis (2002),Vaitkus and Bubinas(2001)

Piscivorous fish Gadus morrhua callaria; Psetta maxima; Stizostedionlucioperca; Salmo trutta m.trutta

Repecka et al. (1994), Bubinasand Vaitonis (2003)

Harvey et al.(2003)

Harvey et al.(2003)

Bubinas andVaitonis (2003),Stankus (2003)

Planktivorous fish Sprattus sprattus balticus; Clupea harengus membras Repecka et al. (1994) Harvey et al.(2003)

Harvey et al.(2003)

Möllmann et al.(2004)

Benthivorous fish Platichthys flesus trachurus; Abramis brama; Vimba vimba Repecka et al. (1994), Bubinasand Vaitonis (2003)

Horppile(1999)

Horppile(1999)

Bubinas andVaitonis (2003),Fishery ResearchLaboratory


Marenzelleria viridis; Pygospio elegans; Hediste diversicolor;Harmothoe sarsi; Oligochaeta spp.; Mesidothea entomon;Corophium spp.; Chironomidae undet.; Turbellaria undet.;Piscicola geometra; Crangon crangon; Gammarus sp.; Jaeraalbifrons; Idothea baltica; Theodoxus fluviatilis; Hydrobia sp.

Olenin (1997), Bubinas andRepecka (2003)

Ostrovski(1984),Wallentinus(1991)

Redant (1989) Olenin (1997),Jarvekiulg (1979),Jansson (1967)


Fabricia sabella; Bathyporea pilosa; Balanus improvisus;Mytilus edulis trossulus; Macoma balthica; Cerastodermaglaucum; Mya arenaria

Olenin (1997), Bubinas andRepecka (2003)

Ostrovski(1984),Wallentinus(1991)

Redant (1989) Olenin (1997),Jarvekiulg (1979),Dolmer (2000)

Macrozooplankton Mysis mixta, Neomysis intiger Witek (1995) Witek (1995) Witek (1995) Viherluoto (2001)Mesozooplankton Acartia sp. ; Nauplii; Evadne nordmanni; Bosmina coregoni

maritima; Cladocerans; RotatoriaCoastal Research andPlanning Institute, localresearch survey

Witek (1995) Harvey et al.(2003),Sandberg et al.(2000)

Gasparini and Castel(1997)


Furcellaria lumbricalis Olenin et al. (2003), CoastalResearch and PlanningInstitute, local researchsurvey

Wallentinus(1991)

AnnualMacrophytes

Ectocarpus siliculosus; Pilayella litoralis Cladophora sp. Ulva sp., Olenin et al. (2003) CoastalResearch and PlanningInstitute, local researchsurvey

Wallentinus(1991)

Phytoplankton Aphanizomenon flos-aquae; Nodularia spumigena;Gomphosphaeria pusilla; Snowella lacustris; Planktonemalauterbornii; Monoraphidium contortum; Skeletonemacostatum;, Diatoma tenuis; Stephanodiscus hantzschii;Aulacoseira islandica; Coscinodiscus granii; Chaetoceroswighamii; Prorocentrum minimum; Prorocentrum balticum;Protoperidinium brevipes; Gonyaulax verior; Peridiniellacatenata; Heterocapsa triquetra; Cryptomonas spp.;Pyramimonas spp.

Lithunian nationalmonitoring data, Center ofMarine Research

Witek (1995)

Detritus Including import of DOC and POC from Curonian Lagoon Pauly et al. (1993a,b); CoastalResearch and PlanningInstitute, local researchsurvey


For example, fisheries tend to change the biomass of piscivorousfish, causing a cascading effect on benthivorous fish and macro-zoobenthos. These cascades are ecosystem specific and need tobe considered when using benthic invertebrates as productivityand eutrophication indicators. In systems with a high fishingpressure on pelagic fish, a similar cascade exists from pelagicfish to mesozooplankton and phytoplankton. The ecologicalfootprint of fisheries in the south-eastern Baltic coastal ecosys-tem varies between systems and is characteristic for each ofthem, dependent mostly on catch species composition and con-dition of the fished stock.

All models are partly affected by difficulties in estimating fishbiomass and their food consumption. Biomass and catch data weremainly available for open areas and were, therefore, mostly extrap-olated for the coastal area. Quantitative data on coastal fish com-munities and their food composition are important for assessingcoastal carbon fluxes and interactions between different ecosystemcomponents.

Odum’s maturity attributes and the indices calculated by ECO-PATH allowed a ranking of coastal ecosystems according to theirlevel of maturity and development. Namely, maturity and develop-

ment decreases in the order Pärnu Bay > Gulf of Riga coast > -Lithuanian coast > Puck Bay > Curonian Lagoon.

Acknowledgments

Part of this study was funded by the Baltic Sea Regional Project(BSRP). We wish to thank all colleagues who have provided dataand local expertise.

Appendix A

The Appendix contains a series of tables that describe the mainspecies comprising the trophic groups in the ECOPATH models foreach study site (Tables A.1-A.5). Tables A.1-A.5 also list the sourcesfor the biomass data, production biomass (P/B) and consumptionbiomass (Q/B) ratios and sources of diet matrix information forthe modelled groups and study sites. The diet matrix is given in de-tail in Tables A.1-A.5, which present the fraction of each prey groupin the diet of the predator groups.

Table A.4Main species and data sources for the Gulf of Riga coast ECOPATH model.

Functional group Main species in the group Biomass P/B Q/B Diet matrix information

Birds Sterna sp., Bucephala clangula; Clangulahyemalis

Institute of Biology, University of Latviacoastal bird monitoring data, 2003–2004 (St�ıpniece (2004)), weightconversion after sources in Cramp andSimmons (1977) and Cramp andSimmons (1985)

Nelson (1979) Nelson (1979) A. St�ıpniece, personalcommunication

Piscivorous fish Perca fluviatilis; Stizostedion lucioperca Latvian Fish Resources Agencymonitoring data, 2002–2004

Thorman andWiederholm(1986), Kangurand Kangur(1998)

Thorman andWiederholm(1986),Kangur andKangur (1998)

Latvian Fish ResourcesAgency stomach contentdata, Thorman andWiederholm (1986),Kangur and Kangur (1998)

Planktivorous fish Clupea harengus Latvian Fish Resources Agencymonitoring data, 2002–2004

Köster (1989),Harvey et al.(2003), Sandberget al. (2000)

Köster (1989),Harvey et al.(2003),Sandberget al. (2000)

Latvian Fish ResourcesAgency stomach contentdata, Köster (1989), Harveyet al. (2003), Sandberget al. (2000)

Benthivorous fish Vimba vimba; Rutilus rutilus; Bliccabjoerkna

Latvian Fish Resources Agencymonitoring data, 2002 – 2004

Horppile (1999) Horppile(1999)

Latvian Fish ResourcesAgency stomach contentdata, Horppile (1999)


Marenzelleria viridis; Macoma baltica;Bathyporeia pilosa; Nereis diversicolor

Latvian national monitoring data,Latvian Institute of Aquatic Ecologydatabase, 1995–2000

Redant (1989),Cederwall andJermakovs (1999),Bergh (1974)

Redant (1989) Redant (1989)


Balanus improvisus; Mytilus edulis;Dreissena polymorpha


Redant (1989),Kautsky (1988),Kautsky et al.(1999)

Redant (1989) Redant (1989)

Macrozooplankton Neomysis integer; Mysis relicta Latvian Fish Resources Agencymonitoring data, 2002–2004

Sandberg et al.(2000)

Sandberget al. (2000)

Sandberg et al. (2000)

Mesozooplankton Eurytemora affinis; Acartia bifilosa;Bosmina o. maritime; Keratella quadrata;Keratella cochlearis

Latvian national monitoring data,Latvian Institute of Aquatic Ecologydatabase, 1995–2000, Strak�e, 2000

Harvey et al.(2003), Sandberget al. (2000)

Harvey et al.(2003),Sandberget al. (2000)

Harvey et al. (2003),Sandberg et al. (2000)


Polysiphonia nigrescens;

Fucus vesiculosus Local research survey, Z. Dek�ere,personal communication

Kotta et al. (2006a,b, 2000), Orav-Kottaand Kotta (2004)

Annualmacrophytes

Ceramium tenuicorne; Enteromorphaintestinalis; Cladophora glomerata

Local research survey, Z. personalcommunication

Kotta et al.(2006a,b, 2000),Orav-Kotta andKotta (2004),Paalme et al.(2002)

Phytoplankton Achnanthes teniata; Chaetoceroswighamii; Melosira arctica; Thalassiosirabaltica; Peridiniella catenata;Aphanizomenon flos-aquae; Anabaenaspp.; Monoraphidium contortum;Oocystis spp.; Skeletonema costatum;Chrysochromulina spp.; Actinocyclusoctonarius; Chaetoceros danicus;Coscinodiscus granii, Thalassiosira baltica.


Wasmund et al.(2001)

– –

Detritus Pauly et al. (1993a,b) – – –


The species composition of the trophic groups included in theECOPATH models differed between the study sites. Birds generallyacted as top predators. Three areas had cormorant colonies (PuckBay, Curonian Lagoon, Pärnu Bay) and scoters, ducks, divers andterns dominated at the remaining sites. The main piscivorous fishspecies were perch (Perca fluviatilis) and pike perch (Stizostedionlucioperca). Only in the areas adjacent to the Baltic deep basins(Puck Bay, Lithuanian coast did cod (Gadus morrhua), sea trout(Salmo trutta m. trutta) and turbot (Psetta maxima) occur. Herring(Clupea harengus) and sticklebacks ( G. aculeatus) comprised theplanktivorous fish group in all models. Smelt (Osmerus eperlanus)were a major component In the Curonian Lagoon, where planktiv-orous fish biomass was low. Benthivorous fish were representedby various cyprinid species, except in Puck Bay, where gobies(Pomatoschistus minutus, Neogobius melanostomus) occurred inlarge numbers. In the systems closest to the Baltic deep basins

(Puck Bay, Lithuanian coast) flounder (Platichthys flesus) was alsocommon. In most study sites the benthic deposit feeder groupconsisted of various polychaetes, oligochaetes and amphipods. Inthe Curonian Lagoon molluscs, snails and chironomid larvae pre-vailed. Molluscs dominated the benthic suspension feeder groupin the models; barnacles (Balanus improvisus), polychaetaes andamphipods were minor components. Macrozooplankton wascomposed of mysid species common in the Baltic Sea (Mysis mixta,Neomysis integer, Mysis relicta) at all sites except the CuronianLagoon, where freshwater species dominated. The mesozooplank-ton community changed from predominantly marine copepods(Acartia, Temora, Pseudocalanus) in Puck Bay towards estuarinespecies (Eurytemora affinis) in the Gulf of Riga and Pärnu Bay studysites. Cladocerans and rotifers occured at all sites. In the CuronianLagoon freshwater cladocerans (Chydorus spaericus, Daphnia lon-gispina) dominated the zooplankton community. Perennial mac-

Table A.5Main species and data sources for the Pärnu Bay ECOPATH model.

Functional group Main species in the group Biomass P/B Q/B Diet matrix information

Birds Phalacrocorax carbo Estonian Marine MonitoringData, average 2001–2005,Veber (2001)

Estonian MarineMonitoring Data,average 2001–2005,Veber (2001)

Estonian MarineMonitoring Data,average 2001–2005, Veber (2001)

Veber (2001)

Piscivorous fish Perca fluviatilis Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008)

Estonian MarineMonitoring Data


Ojaveer et al. (2003)

Planktivorous fish Clupea harengus membras Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008, 2004a), Ojaveeret al. (1999)

Estonian MarineMonitoring Data,Kotta et al. (2004a),Ojaveer et al. (1999)

Estonian MarineMonitoring Data,Ojaveer et al.(2003)


Benthivorous fish Rutilus rutilus Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008)





Macoma balthica; Corophium volutator;Marenzelleria neglecta; Hedistediversicolor

Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008, 2003, 2006a,b)

Estonian MarineMonitoring Data,Kotta et al. (2003,2008)

Estonian MarineMonitoring Data,Kotta et al. (2001),Kotta et al. (2008)

Orav-Kotta et al. (2009),Kotta et al. (2000, 2005,2004b), Orav-Kotta (2004),Orav-Kotta and Kotta(2004, 2003)


Dreissena polymorpha; Balanusimprovisus; Mytilus trossulus

Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008, 2006a,b, 2005,2003, 1998)


Kotta andMøhlenberg(2002), Kotta et al.(2005)

Lauringson et al. (2007),Kotta et al. (2007, 2005),Orav-Kotta (2004)

Macrozooplankton Neomysis integer Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (1998, 2007, 2004a), Kottaand Kotta (2001), Ojaveer et al.(1999)

Estonian MarineMonitoring Data,Kotta et al. (2004a,2007)

Estonian MarineMonitoring Data,Kotta et al. (2004)

Unpublished feeding trials(personal comment byIlmar Kotta)

Mesozooplankton Eurytemora affinis; Acartia bifilosa;Synchaeta baltica; Keratella cochlearis;Keratella quadrata; Bosmina coregoni

Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008, 2004a), Ojaveeret al. (1999)

Estonian MarineMonitoring Data,Kotta et al. (2004a)

Estonian MarineMonitoring Data,Kotta et al. (2008,2004a), Ojaveeret al. (1999)

Simm et al. (2006), Harveyet al. (2003), Sandberget al. (2000)


Fucus vesiculosus Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2000), Martin et al.(2003), Kotta et al. (2008)

Kotta et al. (2006a,b,2000), Orav-Kottaand Kotta (2004)

Annualmacrophytes

Pilayella littoralis; Ulva intestinalis Estonian Marine MonitoringData, average 2001–2005,Martin et al. (2003), Paalmeet al. (2002)

Kotta et al. (2006a,b,2000), Orav-Kottaand Kotta (2004),Paalme et al. (2002)

Phytoplankton Thalassiosira baltica; Aphanizomenon flos-aquae; Achnanthes taeniata; Peridiniellacatenata; Scrippsiella hangoei;Mesodinium rubrum; Chaetoceroswighamii; Melosira arctica; Scrippsiellamalmogiense; Nodularia spumigena;Skeletonema costatum; Monoraphidiumcontortum; Heterocapsa triquetra

Estonian Marine MonitoringData, average 2001–2005, Kottaet al. (2008, 2004a), Ojaveeret al. (1999)

Kotta et al. (2008),Wasmund et al.(2001), Renk andOchocki (1999),Ojaveer (1995)

Detritus Pauly et al. (1993a,b)

Table A.6Diet matrix table for the Puck Bay ECOPATH model.

Prey/predator 1 2 3 4 5 6 7 8

1 Birds2 Piscivorous fish 0.0013 Planktivorous fish 0.014 0.74 Benthivorous fish 0.015 0.115 Benthic deposit feeders 0.035 0.12 0.656 Benthic suspension feeders 0.624 0.277 Macrozooplankton 0.07 0.01 0.048 Mesozooplankton 0.75 0.1 0.49 Perennial macrophytes 0.125 0.2

10 Annual macrophytes 0.187 0.24 0.04 0.211 Phytoplankton 0.6 0.3 0.912 Detritus 0.6 0.3 0.3 0.113 Import


Table A.7Diet matrix table for the Curonian Lagoon ECOPATH model.


1 Birds2 Piscivorous fish 0.14 0.1253 Planktivorous fish 0.0054 Benthivorous fish 0.655 0.55 Benthic deposit feeders 0.014 0.66 Benthic suspension feeders 0.037 Macrozooplankton 0.055 0.0058 Mesozooplankton 1 0.02 0.2 0.19 Perennial macrophytes

10 Annual macrophytes11 Phytoplankton 0.316 0.4 0.2 0.712 Detritus 0.684 0.6 0.6 0.213 Import 0.2 0.306 0.345

Table A.8Diet matrix table for Lithuanian coast ECOPATH model.


1 Birds2 Piscivorous fish 0.073 Planktivorous fish 0.12 0.57 0.244 Benthivorous fish 0.025 Benthic deposit feeders 0.44 0.36 0.01 0.066 Benthic suspension feeders 0.42 0.537 Macrozooplankton 0.118 Mesozooplankton 0.99 0.06 0.01 0.689 Perennial macrophytes

10 Annual macrophytes11 Phytoplankton 0.23 0.88 0.3 0.6712 Detritus 0.77 0.11 0.02 0.3313 Import

Table A.9Diet matrix table for the Gulf of Riga coast ECOPATH model.


1 Birds2 Piscivorous fish3 Planktivorous fish 0.05 0.44 Benthivorous fish 0.175 Benthic deposit feeders 0.13 0.16 Benthic suspension feeders 0.95 0.457 Macrozooplankton 0.3 0.38 Mesozooplankton 0.7 0.1 0.59 Perennial macrophytes 0.05

10 Annual macrophytes 0.311 Phytoplankton 0.1 0.2 0.812 Detritus 0.1 1 0.8 0.3 0.213 Import

Table A.10Diet matrix table for the Pärnu Bay ECOPATH model.


1 Birds2 Piscivorous fish 0.7183 Planktivorous fish 0.141 0.1774 Benthivorous fish 0.141 0.2745 Benthic deposit feeders 0.348 0.9076 Benthic suspension feeders7 Macrozooplankton 0.2 0.058 Mesozooplankton 0.95 0.05 0.69 Perennial macrophytes 0.047

10 Annual macrophytes 0.04611 Phytoplankton 0.95 0.2 0.812 Detritus 1 0.2 0.213 Import



rophytes were represented by the flowering plants Z. marina inPuck Bay and the freshwater/estuarine Potamogeton perfoliatus inthe Curonian Lagoon. At the other study sites macroalage growingon rocky substrates prevailed. Annual macrophytes were com-posed of filamentous macroalgae in all study areas. A large numberof marine and freshwater species made of the phytoplanktoncommunity in the study areas. Cyanobacteria occurred at all sites,but they were the dominant phytoplankton group only for theCuronian Lagoon. Autochthonous production was the sole sourceof detritus in all systems except the Lithuanian coast, which in-cluded detritus import form the Curonian Lagoon.

The diet matrix was very similar for the lower trophic levels inall models. Mesozooplankton were predominantly herbivorous;macrozooplankton fed on a mix of mesozooplankton, phytoplank-ton and detritus, while benthic suspension feeders utilized phyto-plankton and, to a lesser degree, detritus. Detritus was the chieffood source of benthic deposit feeders. Benthivorous fish preyedmainly on benthic deposit feeders; at the Lithuanian coast, wherecod occurred, this group was partially piscivorous. Planktivorousfish fed predominantly on mesozooplankton in all areas. The foodcomposition of piscivorous fish and the top predators, birds, washowever dependent on the species composition of the group ineach model.

References

Abarca-Arenas, L.G., Ulanowicz, R.E., 2002. The effects of taxonomic aggregation onnetwork analysis. Ecological Modelling 149, 285–296.

Andrulewicz, E., Kruk-Dowgiałło, L., Osowiecki, A., 2004. An expert judgementapproach to designating ecosystem typology and assessing the health of theGulf of Gdansk. In: Schernewski, G., Löser, N. (Eds.), Managing the Baltic Sea.Coastline Reports 2. ISSN 0928-2734, pp. 53–61.

Anon, 2004. Workshop on Ecopath modelling of Baltic Sea carbon and nutrientnetworks, October 18–22, 2004, Jurmala, Latvia.

Anon, 2007. Report of the ICES/HELCOM Working Group on Integrate Assessmentsof the Baltic Sea (WGIAB), ICES CM 2007/BCC:04. Ref. HELCOM MONAS. March12-16, 2007, Hamburg, Germany. <http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=199>.

Baird, D., Ulanowicz, R.E., 1993. Comparative study on the trophic structure cyclingand ecosystem properties on four tidal estuaries. Marine Ecology ProgressSeries 99, 221–237.

Baird, D., McGlade, J.M., Ulanowicz, R.E., 1991. The comparative ecology of sixmarine ecosystem. Philosophical Transactions of the Royal Society of London B333, 15–29.

Bergh, G., 1974. Growth and production of Macoma balthica (L.) in a northern Balticsoft bottom. Ophelia (Suppl. 1), 31–48.

Bray, T., 1999. A collection of empirical relations for use in ecological modeling.NAGA, The ICLARM Quarterly 22 (3), 24–28.

Bubinas, A., Repecka, R., 2003. Hydrobiological studies of the coastal zone of theBaltic Sea and the Curonian Lagoon: preface. Acta Zoologica Lituanica 13 (2),95–96.

Bubinas, A., Vaitonis, G., 2003. The analysis of the structure, productivity, anddistribution of zoobenthocenoses in the Lithuanian economic zone of the BalticSea and the importance of some benthos species to fish diet. Acta ZoologicaLituanica 13 (2), 114–124.

Bzoma Sz., 2004. Kormoran Phalacrocorax carbo (L.) w strukturze troficznejZat.Gdanskiej. Manuscript Ph.D. Thesis, Universtet Gdanski, Gdynia.

Carrer, S., Optiz, S., 1999. Trophic network of a shallow water area in the northernpart of the Lagoon of Venice. Ecological Modelling 124, 183–219.

Cederwall, H., Jermakovs, V., 1999. Growth and production of threemacrozoobenthic species in the Gulf of Riga, including comparisons withother areas. Hydrobiologia 393, 201–210.

Chang, K., Hanazato, T., 2004. Predation impact of Leptodora kinditti on populationdynamics and morphology of Bosmina fatalis and B. longirostis in a mesocosm.Freshwater Biology 49, 253–264.

Christensen, V., 1995. Ecosystem maturity – towards quantification. EcologicalModelling 77, 3–32.

Christensen, V., 1998. Fishery-induced changes in a marine ecosystem: insight frommodels of the Gulf of Thailand. Journal of Fish Biology 53, 128–142.

Christensen, V., Pauly, D., 1992. ECOPATH II – a software for balancing steady stateecosystem models and calculating network characteristics. EcologicalModelling 61, 169–185.

Christensen, V., Pauly, D., 1993. Flow characteristic of aquatic ecosystems. In:Cristiansen, V., Pauly, D. (Eds.), Trophic Models of Aquatic Ecosystems. ICLARM,Manilia, pp. 338–352.

Christensen, V., Walters, C.J., 2004. Ecopath with Ecosim: methods, capabilities andlimitations. Ecological Modelling 172 (2-4), 109–139.

Christensen, V., Walters, C.J., Pauly, D., 2004. ECOPATH with ECOSIM: A User’sGuide. Fisheries Centre, University of British Columbia, Vancouver, Canada, 151p.

Cohen, E.B., Grosslein, M.D., 1987. Production on Georges Bank compared withother shelf ecosystems. In: Backus, R.H., Bourne, D.W. (Eds.), Georges Bank. MITPress, Cambridge. p. 37.

Coll, M., Shannon, L.J., Moloneyc, C.L., Palomera, I., Tudelad, S., 2006. Comparingtrophic flows and fishing impacts of a NW Mediterranean ecosystem withcoastal upwelling systems by means of standardized models and indicators.Ecological Modelling 198, 53–70.

Costa, J.L., Assis, C.A., Almeida, P.R., Moreira, F.M., Costa, M.J., 1992. On the food ofthe European eel, Anguilla anguilla (L.), in the upper zone of the Tagus estuary,Portugal. Journal of Fish Biology 41, 841–850.

Cramp, S., Simmons, K.E.L. (Eds.), 1977. Handbook of the Birds of Europe the MiddleEast and North Africa. Ostrich to Ducks, vol. I. Oxford University Press, p. 722.

Cramp, S., Simmons, K.E.L. (Eds.), 1985. Handbook of the Birds of Europe, the MiddleEast and North Africa. Terns to Woodpeckers, vol. IV. Oxford University Press.

Daunys, D., Olenin, S., 1999. Bottom macrofauna communities in the littoral zone ofthe Kurðiø marios Lagoon. Ekologija 2, 19–27. ISSN 0235-7224 (in Lithuanian).

Dolmer, P., 2000. Feeding activity of mussels Mytilus edulis related to near-bedcurrents and phytoplankton biomass. Journal of Sea Research 44 (3–4), 221–231.

Duarte, C.M., 1995. Submerged aquatic vegetation in relation to different nutrientregimes. Ophelia 41, 87–112.

Eberhard, G., 2004. The sea attacks. LIFE Nature Project ‘Coastal biotope protectionand management in Latvia’. University of Latvia, 23 pp (in Latvian).

Eliott, M., Quintino, V., 2007. The estuaries quality paradox: environmentalhomeostasis and the difficulty of detecting anthropogenic stress in naturalstressed areas. Marine Pollution Bulletin 54, 640–645.

Falkowska, L., Bolałek, J., 1991. Nitrogen and phosphorus exchange in coastal zonebetween sea and atmosphere. Oceanologia 30, 47–56.

Finn, J.T., 1976. Measure of ecosystem structure and functions derived from theanalysis of flows. Journal of Theoretical Biology 56, 363–380.

Folke, C., Kautsky, N., Berg, H., Jansson, A., Troell, M., 1998. The ecological footprintconcept for sustainable seafood production: a review. Ecological Applications 8(1), 63–71.

Gasparini, S., Castel, J., 1997. Autotrophic and heterotrophic nanoplankton in thediet of the estuarine copepods Eurytemora affinis and Acartia bifilosa. Journal ofPlankton Research 19 (7), 877–890.

Haluch, M., Skóra, K., 1997. Food of sea trout (Salmo trutta m. trutta L.) caught in theGulf of Gdansk in 1994–1995 (Baltic Sea). Bulletin of the Sea Fisheries Institute3 (142), 55–71.

Hannon, B., 1973. The structure of ecosystems. Journal of Theoretical Biology 41,535–546.

Hannon, B., Joiros, C., 1989. A seasonal analysis of the southern North Seaecosystem. Ecology 70, 1916–1934.

Harvey, C.J., Cox, S.P., Essington, T.E., Hansson, S., Kitchell, J.F., 2003. An ecosystemmodel of food web and fisheries interactions in the Baltic Sea. ICES Journal ofMarine Science 60, 939–950.

Hoenig, J.M., 1983. Empirical use of longevity data to estimate mortality rates.Fishery Bulletin 82 (1), 898–903.

Horackiewicz, J., Skóra, E.K., 1998. A seasonal pattern of occurrence of gobid fish(Gobidae) in shallow littoral zone (0–1 m depth) of Puck Bay. OceanologicalStudies No. 3, vol. XXVII. Gdynia, UG.

Horppile, J., 1999. Diel changes in diet composition of an omnivorous cyprinid – apossible source of error in estimating food consumption. Hydrobiologia 400,33–39.

ICES, 2000. Report of the Baltic Fisheries Assessment Working Group. ICES C.M.2000/ACFM: 14.

ICES WGBFAS, 2005. Report of the Baltic Fisheries Assessment Working Group(WGBFAS), 12–21 April 2005, Hamburg, Germany (ICES CM 2005 ACFM: 19).

Jackowski, J., 1998. Stan tarlisk w Zatoce Puckiej. Studia i Materiały MIR., Ser. B no.71. Gdynia.

Jackowski, E., 2002. Ryby Zatoki Puckiej. MIR Gdynia 2002, 108 p.Jansson, A.M., 1967. The Food-web of the Cladophora-belt Fauna. Department of

Zoology and Asko Laboratory, University of Stockholm, Stockholm, Sweden.Jarre-Teichman, A., 1995. A seasonal mass-balance model of carbon flows in the

central Baltic Sea with emphasis on the upper trophic level. ICES C.M.: 1995/T6.Jarvekiulg, A. 1979. Benthos of the Eastern Part of the Baltic Sea. Composition and

Ecology of Distribution. Tallinn, Valgus, 382 pp. (in Russian).Jokšas, K., 1994. Hydrochemical composition and zonation of bottom layer water of

eastern Baltic Sea. Annales Geographicae 28, 256–274 (in Lithuanian).Jokšas, K., Galkus, A., Stakeniene, R., 1998. Geochemical peculiarities of Curonian

lagoon bottom sediments and factors of their formation. The GeographicalYearbook 31, 123–144 (in Lithuanian).

Jorgensen, S.E., Nielsen, S.N., Jorgensen, L.A., 1991. Handbook of ecologicalparameters and ecotoxicology. Elsevier Science Publishing, New York. 1264 pp.

Kangur, A., Kangur, P., 1998. Diet composition and size-related changes in thefeeding of pikeperch, Stizostedion lucioperca (Percidae) and pike, Esox lucius(Esocidae) in the lake Peipsi (Estonia). Italian Journal of Zoology 65, 255–259.

Kautsky, H., 1988. Factors structuring phytobenthic communities in the Baltic Sea.Dissertation, Dep. Zoology, Univ. Stockholm, 29 pp.

Kautsky, U., 1995. Ecosystem processes in the Coastal Areas of the Baltic Sea. Ph.D.Dissertation, 25 pp.

Kautsky, U., Kautsky, H., 1995a. Production and nutrient dynamics of coastalvegetation covered bottoms of the Baltic Sea. In: Elefteriou, A., Ansell, A., and

http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=199

http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=199


Smith Jr., C. (Eds.), Biology and Ecology of Shallow Coastal Waters. Olsen &Olsen, Fredensborg, pp. 31–38.

Kautsky, U., Kautsky, H., 1995b. Ecosystem processes in coastal areas of the BalticSea. Doctoral Dissertation, Stockholm University, Sweden.

Kautsky, H., Martin, G., Mäkinen, A., Borgiel, M., Vahteri, P., Rissanen, J., 1999.Structure of phytobenthic and associated animal communities in the Gulf ofRiga. Hydrobiologia 393, 191–200.

Kay, J.J., Graham, L.A., Ulanowicz, R.E., 1989. A detailed guide to network analysis.Coastal Estuarine Studies 32, 15–61.

Kompowski, A., 1994. Badania and bellona (Belone belone L.) z Zat. Puckiej. PraceMor. Inst. Ryb. Tom 13, Ser. A Gdynia 1994.

Kornilovs, G., 1994. The spawning grounds and embryonal development of Balticherring in the Gulf of Riga. Ph.D. Thesis, University of Latvia, Riga, 40 pp.

Korzeniewski, K. (Ed.), 1993. Zatoka Pucka. Instytut Oceanografii UniwersytetuGdanskiego, Gdansk, 524 pp.

Köster, F.W., 1989. Feeding activity of Baltic herring in the Bornholm Basin. ICESC.M./J: 16, 12 pp.

Kotta, I., Kotta, J., 2001. Distribution of mysids on the bank slopes in the Gulf of Riga.Proceedings of the Estonian Academy of Sciences: Biology, Ecology 50, 14–21.

Kotta, J., Møhlenberg, F., 2002. Grazing impact of Mytilus edulis and Dreissenapolymorpha (Pallas) in the Gulf of Riga, Baltic Sea estimated from biodepositionrates of algal pigments. Annales Zoologici Fennici 39, 151–160.

Kotta, J., Orav, H., Kotta, I., 1998. Distribution and filtration activity of Zebra mussel,Dreissena polymorpha (Pallas) in the Gulf of Riga and the Gulf of Finland.Proceedings of the Estonian Academy of Sciences: Biology, Ecology 47 (1), 32–41.

Kotta, J., Paalme, T., Martin, G., Makinen, A., 2000. Major changes in macroalgaecommunity composition affect the food and habitat preference of Idotheabaltica. Hydrobiologia 85 (5–6), 697–705.

Kotta, J., Orav, H., Sandberg-Kilpi, E., 2001. Ecological consequence of theintroduction of the polychaete Marenzelleria viridis into a shallow waterbiotope of the northern Baltic Sea. Journal of Sea Research 46, 273–280.

Kotta, I., Orav-Kotta, H., Kotta, J., 2003. Macrozoobenthos assemblages in highlyproductive areas of the Estonian coastal sea. Proceedings of the EstonianAcademy of Sciences: Biology, Ecology 52, 149–165.

Kotta, J., Simm, M., Kotta, I., Kanošina, I., Kallaste, K., Raid, T., 2004a. Factorscontrolling long-term changes of the eutrophicated ecosystem of Pärnu Bay,Gulf of Riga. Hydrobiologia 514, 259–268.

Kotta, J., Torn, K., Martin, G., Orav-Kotta, H., Paalme, T., 2004b. Seasonal variation ofinvertebrate grazing on Chara connivens and C. tomentosa in Kõiguste Bay, NEBaltic Sea. Helgoland Marine Research 58, 71–76.

Kotta, J., Orav-Kotta, H., Vuorinen, I., 2005. Field measurements on the variability inbiodeposition and grazing pressure of suspension feeding bivalves in thenorthern Baltic Sea. In: Dame, R., Olenin, S. (Eds.), The Comparative Roles ofSuspension Feeders in Ecosystems. Springer, The Netherlands, Dordrecht, pp.11–29.

Kotta, J., Orav-Kotta, H., Paalme, T., Kotta, I., Kukk, H., 2006a. Seasonal changes insitu grazing of the mesoherbivores Idotea baltica and Gammarus oceanicus onthe brown algae Fucus vesiculosus and Pylaiella littoralis in the central Gulf ofFinland, Baltic Sea. Hydrobiologia 554, 117–125.

Kotta, J., Kotta, I., Simm, M., Lankov, A., Lauringson, V., Põllumäe, A., Ojaveer, H.,2006b. Ecological consequences of biological invasions: three invertebrate casestudies in the north-eastern Baltic Sea. Helgoland Marine Research 60, 106–112.

Kotta, I., Kotta, J., Herkül, K., 2007. Seasonal changes in the population structure andlife cycle of Neomysis integer in Pärnu Bay, northeastern Baltic Sea. Proceedingsof the Estonian Academy of Sciences: Biology, Ecology 56, 312–325.

Kotta, J., Lauringson, V., Martin, G., Simm, M., Kotta, I., Herkül, K., Ojaveer, H., 2008.Gulf of Riga and Pärnu Bay. In: Schiewer, U. (Ed.), Ecology of Baltic CoastalWaters, Ecological Studies, vol. 197. Springer, pp. 217–243.

Kruk-Dowgiałło, L., 1991. Long-term changes in the structure of underwatermeadows of the Puck Lagoon. Acta Ichthyologica et Piscatoria 21, 77–84.

Kruk-Dowgiałło, L. (Ed.), 2000. Przyrodnicza waloryzacja morskich czesci obszarówchronionych HELCOM BSPA województwa pomorskiego cz. 3 Nadmorski ParkKrajobrazowy. CRANGON 7 Centrum Biologii Morza PAN, Gdynia, 187 pp.

Labanauskas, V., 2000. Communities of marine macrophytobenthos along theLithuanian coastline of the Baltic Sea. Botanica Lithuanica 6 (4), 403–413 (inLithuanian).

Lauringson, V., Mälton, E., Kotta, J., Kangur, K., Orav-Kotta, H., Kotta, I., 2007.Environmental factors influencing the biodeposition of the suspension feedingbivalve Dreissena polymorpha (Pallas): comparison of brackish and fresh waterpopulations in the Northern Baltic Sea and Lake Peipsi. Estuarine Coastal andShelf Science 75, 459–467.

Leontief, W.W., 1951. The Structure of the US Economy. Oxford University Press,New York.

Lindeman, R.L., 1942. The trophic-dynamic aspect of ecology. Ecology 23, 399–418.Lizinska, A., 2002. Seasonal and Daily Distribution of Commercial and Non-

commercial Fish in Shallow Inshore Waters of the Gulf of Gdansk.Oceanological Studies, vol. XXXI(No 1–2). Univ. Gdansk, pp. 31–42.

Lobry, J., David, V., Pasquaud, S., Lapage, M., Sautour, B., Rochard, E., 2008. Diversityand stability of an estuarine trophic network. Marine Ecology Progress Series358, 13–25.

Lozys, L., 2002. Peculiarities of pikeperch (Sander lucioperca) and perch (Perchafluviatilis) ecology in the Curonian lagoon and the coastal zone of the Baltic Sea.Ph.D. Thesis.

Majkowski, J., 1982. Usefulness and applicability of sensitivity analysis in amultispecies approach to fisheries management. In: Pauly, D., Marphy, G.I.

(Eds.), 1993 Theory and Management of Trophical Fisheries. ICLAMR ConferenceProceedings, ICLARM, Manilia, Philipines, 360pp.

Mankowski, W. (Ed.), 1978. Produktywnosc ekosystemu Morza Baltyckiego.Ossolineum, Wroclaw, 360 pp.

Mann, K.H., Field, J.G., Wulff, F., 1989. Network analysis in marine ecology: anassessment. In: Wulff, F.J., Field, G., Mann, K.H., (Eds.), Network Analysis inMarine Ecology. Methods and Applications. Springer Verlag, Berlin, pp. 261–282.

Martin, G., 2000. Phytobenthic communities of the Gulf of Riga and the inner sea ofthe West-Estonian Archipelago. Diss. Biol. Univ. Tartuensis. 64. p. 140.

Martin, G., Torn, K., Kotta, J., Orav-Kotta, H., 2003. Estonian marine phytobenthosmonitoring programme: preliminary results and future perspectives.Proceedings of the Estonian Academy of Sciences: Biology, Ecology 52, 112–124.

McLusky, D.S., 1981. The estuarine ecosystem. Blackie Press, Glasgow. 215 pp..Meissner, 1997. Zimowane ptakow wodnych na Zatoce Gdanskiej w sezonie 1996/

1997. Not. Orn. 37, pp. 351–354.Möllmann, C., Kornilovs, G., Fetter, M., Köster, F.W., 2004. Feeding ecology of central

Baltic Sea herring and sprat. Journal of Fish Biology 65 (6), 1563–1581.Monaco, M.E., Ulanowicz, R.E., 1997. Comparative ecosystem trophic structure of

three U.S. mid-Atlantic estuaries. Marine Ecology Progress Series 161, 239–254.Monakov, A.B., 1998. Feeding of freshwater invertebrates. Institute for the

ecological and evolution problems RAS, 319 pp. (in Russian).Nelson, B., 1979. Seabirds, Their Biology and Ecology. A&S Publishers Inc., New York.

219.Nilsson, P., Jansson, M., 2002. Hydrodynamic control of nitrogen and phosphorus

turnover in an eutrophicated estuary in the Baltic. Water Research 36 (18),4616–4626.

Odum, E.P., 1969. The strategy of ecosystem development. Science 104, 262–270.Odum, E., 1971. Fundaments of Ecology. Saunders, Philadelphia. 574 p.Ojaveer, E. (Ed.), 1995. Ecosystem of the Gulf of Riga between 1920 and 1990.

Estonian Academy Publishers, Tallinn.Ojaveer, H., Lankov, A., Eero, M., Kotta, J., Kotta, I., Lumberg, A., 1999. Changes in the

ecosystem of the Gulf of Riga from the 1970s to the 1990s. ICES Journal ofMarine Science 56, 33–40.

Ojaveer, E., Pihu, E., Saat, T. (Eds.), 2003. Fishes of Estonia. Estonian Academy ofPublishers, Tallinn.

Okey, T.A., Pauly, D., 1999. A Mass-balanced Model of Trophic Flows in PrinceWilliam Sound: Decompartmentalizing Ecosystem Knowledge. EcosystemApproaches for Fisheries Management. Alaska Sea Grant College Program, AK-SG-99-01, pp. 621–635.

Olenin, S., 1997. Comparative study of the south-eastern Baltic coastal zone and theCuronian Lagoon bottom communities. In: Andrushaitis, A. (Ed.), Proceedings ofthe 13th Baltic Marine Biologists Symposium, Riga. Institute of Aquatic Ecology,University of Latvia, pp. 151–159.

Olenin, S., Daunys, D., Labanauskas, V., 1996. Classification principles of theLithuanian coastal biotopes. Annals of Geography (Vilnius) 29, 218–231 (inLithuanian with English summary).

Olenin, S., Daunys, D., Leinikki, J., 2003. Biodiversity study and mapping of marinehabitats in the vicinity of the B�utinge Oil Terminal Lithuanian coastal zoneBaltic Sea. Joint Finnish – Lithuanian Project Report. Coastal Research andPlanning Institute, Klaipeda University, Klaipeda, p. 30.

Orav-Kotta, H., 2004. Habitat choice and feeding activity of benthic suspensionfeeders and mesograzers in the northern Baltic Sea. Dissertationes BiologicaeUniversitatis Tartuensis, 89, Tartu University Press, 117 pp.

Orav-Kotta, H., Kotta, J., 2003. Seasonal variations in the grazing of Gammarusoceanicus, Idotea baltica, and Palaemon adspersus on benthic macroalgae.Proceedings of the Estonian Academy of Sciences: Biology, Ecology 52, 141–148.

Orav-Kotta, H., Kotta, J., 2004. Food and habitat choice of the isopod Idotea baltica inthe northeastern Baltic Sea. Hydrobiologia 514, 79–85.

Orav-Kotta, H., Kotta, J., Herkül, K., Kotta, I., Paalme, T., 2009. Seasonal variability inthe grazing potential of the invasive amphipod Gammarus tigrinus and thenative amphipod Gammarus salinus in the northern Baltic Sea. BiologicalInvasions 11, 597–608.

Ostrovski, E., 1984. Production of macrozoobenthos in the southern Baltic Sea. In:Essays on the Baltic Sea Biological Productivity (Ocherki po biologicheskojproduktivnosti Baltijskogo morja, T.1), Moscow, pp. 130–154 (in Russian).

Paalme, T., Kukk, H., Kotta, J., Orav, H., 2002. ‘‘In vitro” and ‘‘in situ” decompositionof nuisance macroalgae Cladophora glomerata and Pilayella littoralis.Hydrobiologia 475/476, 469–476.

Pauly, D., 1989. Food consumption by tropical and temperate fish populations:some generalizations. Journal of Fish Biology 35 (Suppl. A), 11–20.

Pauly, D., Christensen, V., 1995. Primary production required to sustain globalfisheries. Nature 374 (6519), 255–257 [Erratum in Nature, 376: 279].

Pauly, D., Soriano-Bartz, M.L., Palomeras, M.L.D., 1993a. Improved construction,parameterization and interpretation of steady state ecosystem models. In:Pauly, D., and Murphy, G.I. (Eds.), Theory and Management of Tropical Fisheries.ICLAMR Conference Proceedings, ICLARM, Manila, Philippines, 360 p.

Pauly, D., Soriano, M., Palomares, M.L., 1993b. On improving the construction,parameterization and interpretation of steady-state multi species models. In:Christensen, V., Pauly, D. (Eds.) Trophic Models of Aquatic Ecosystems. ICLARMConference Proceedings No. 26. ICLARM, Manila, Philippines, 90 p.

Pauly, D., Christensen, V., Froese, R., Palomares, M.L.D., 2000. Fishing down aquaticfood webs. American Scientist 88, 46–51.

Pelczarski, W., 1999. Puck Bay (Southern Baltic): fishery management in a veryspecific brackish water system (Extended abstract). ICES Journal of MarineScience 56 (Suppl.), 128–130.


Pliuraite, V., 2001. Species diversity of zooplankton in the Curonian Lagoon in 2001.Acta Zoologica Lituanica 13 (2), 106–113.

Polovina, J.J., 1984. Model of a coral reef ecosystems I. The ECOPATH model and itsapplication to French Frigate Shoals. Coral Reefs 3 (1), 1–11.

Razinkovas, A., Gasi�unaite, Z.R., 1999. The potential grazing by zooplankton andnektobenthic species on phytoplankton in an estuarine system: the KuršiuzMarios (Curonian) lagoon. In: Heiskanen, A.-S., Lundsgaard, C., Reigstadt, M.,Olli, K., Floderus, S. (Eds.), Sedimentation and Recycling in Aquatic Ecosystems.Finnish Environment. Finnish Environment Institute, Nr. 263, ISSN 1238-7312,pp. 44–51.

Redant, F., 1989. Productivity of Epibenthic Species: A Review. ICES C.M.: 1989/L: 2,32 pp.

Renk, H., Ochocki, S., 1999. Primary production in the southern Baltic Seadetermined from photosynthetic light curves. Bulletin of Sea FisheriesInstitute 3 (148), 23–40.

Repecka, R., 1997. Investigation of abundance and topographical structure ofcommercial fish in Curonian lagoon. Report for Lithuanian HydrobiologicalSociety (in Lithuanian).

Repecka, R., Mileriene, E., Bubinas, A., 1994. Assessment of the commercial fishstocks in the Baltic Sea. In: Fishery and Aquaculture in Lithuania. Klaipeda, pp.15–30 (in Lithuanian).

Repecka, R., Lozys, L., Ådjers, K., 2002a. Investigations of fish abundance accordingto the monitoring programme in Curonian lagoon 1992–2000. Fishery inLithuania, vol. IV, pp. 133–144 (in Lithuanian with English summary).

Repecka, R., Lozys, L., Ådjers. K., 2002. Dynamics of fish abundance according to themonitoring programme in the Curonian Lagoon in 1992–2000. In: Symposiumon the Occasion of the 80th Anniversary of the Sea Fisheries Institute-Book ofabstracts. Gdynia, 22–23 June 2001. P. 16-17.

Rudzianskiene, G., 1994. The contemporary role of predatory fish in the Kursiumarios lagoon. In: Fishery and Aquaculture in Lithuania (in Lithuanian).

Rumohr, H., Brey, T., Ankar S., 1987. A compilation of biometric conversion factorsfor benthic invertebrates of the Baltic Sea. Baltic Marine Biological Publication9, 56 pp.

Rybaczyk, H., Elkaim, B., Ochs, L., Loquet, N., 2003. Analysis of the trophic network ofmacrotadial ecosystem: the Bay of Somme (Eastern channel). Estuarine Coastaland Shelf Science 58, 405–421.

Sandberg, J., Elmgren, R., Wulff, F., 2000. Carbon flows in Baltic Sea food webs – a re-evaluation using a mass balance approach. Journal of Marine Systems 25 (3–4),249–260.

Sapota, M.R., Skóra, K.E., 1996. Fish abundance in shallow inshore waters of the Gulfof Gdansk. Proceedings of Polish–Swedish Symposium of Baltic Costal FisheriesResources and Management, 2–3 April 1996 SFI, Gdynia, Poland, October 1996.

Simm, M., Lankov, A., Põllupüü, M., Ojaveer, H., 2006. Estimation of ConsumptionRates of the Predatory Cladoceran Cercopagis pengoi in Laboratory Conditions.Estonian Marine Institute Report Series, vol. 14, pp. 42–47.

Stankus, S., 2003. The peculiarities of turbot (Psetta maxima L.) biology and their rolein the ecosystem of the Baltic Sea coastal zone of Lithuania. Acta ZoologicaLituanica 13 (2), 217–238.

Stempniewicz, L., Meissner, W., 1999. Assessment of the zoobenthos biomass yearlydiving ducks wintering in the Gulf of Gdansk (southern Baltic Sea). OrnisSvecica 9, 143–154.

Stıpniece, A., <http://www.lva.gov.lv/monitor/dati/2003/mon_proj_2003.htm>2004. Coastal bird monitoring 2003–2004. Report to the Latvian Ministry ofEnvironment. Institute of Biology, University of Latvia, 48 pp. (in Latvian).

Strak�e, S., 2000. Variations of mesozooplankton species composition, abundance,and biomass in the littoral zone of the Gulf of Riga, Latvia. Journal ofProceedings of the Latvian Academy of Sciences, Section B 54 (5/6), 155–159.

Sushchenia, L.M., 1975. Quantitative aspects of crustacean feeding, Minsk, Nauka ITechnika (in Russian).

Švazas, S., Dagys, M., Zydelis, R., Raudonikis, L., 2001. Changes in numbers anddistribution of wintering waterfowl populations in Lithuania in the 20thcentury. Acta Zoologica Lituanica 11 (3), 243–254.

Szypula, J., Wlodzimierz, G., Wyszynski, M., 1997. Feeding of Baltic herring andsprat in the period 1986–1996 in relation to their state and biomass. Bulletin ofthe Sea Fisheries Institute 3, 73–83.

Szyrmer, J., Ulanowicz, R.E., 1987. Total flows in ecosystems. Ecological Modelling35, 123–136.

Thorman, S., Wiederholm, A., 1986. Food, habitat and time niches in a coastal fishspecies assemblage in a brackish water bay in the Bothnian Sea, Sweden.Journal of Experimental Marine Biology and Ecology 95, 67–86.

Uitto, A., 1996. Contribution of nanoprotists to metazooplankton diet in amesocosm experiment in the coastal northern Baltic. Journal of PlanktonResearch 18 (11), 2119–2137.

Ulanowicz, R.E., 1986. Growth and Development: Ecosystems Phenomenology.Springer, New York.

Ulanowicz, R.E., 1995. Ecosystem trophic foundations: Lindeman exonerata. In:Patten, B.C., Jorgensen, S.E. (Eds.), Complex Ecology: The Part-Whole Relation inEcosystems. Prentice Hall, Englewoods Cliffs, New Jersey, pp. 549–560.

Ulanowicz, R.E., 2003. Some steps toward a central theory of ecosystem dynamics.Computational Biology and Chemistry 27, 523–530.

Ulanowicz, R., Puccia, C.J., 1990. Mixed trophic impacts in ecosystems. Coenoses 5,7–16.

Vaitkus, G., Bubinas, A., 2001. Modelling of sea duck spatial distribution in relationto food resources in Lithuanian offshore waters under the gradient of winterclimatic conditions. Acta Zoologica Lituanica 11 (3), 288–302.

Vasconcellos, M., Mackinson, S., Sloman, K., Pauly, D., 1997. The stability of trophicmass-balance models of marine ecosystems a comparative analysis. EcologicalModelling 100, 125–134.

Veber, T., 2001. Kormoranide ja kalanduse vahelised interaktsioonid Eestirannikumeres. M. Sc., Thesis, University of Tartu, Faculty of Biology andGeography.

Viherluoto, M., 2001. Food selection and feeding behaviour of Baltic Sea mysidshrimps. W. &. A. de Nottbeck Foundation Sci. Rep. 23, pp. 1–35.

Villanueva, M.C., Laleye, P., Albaret, J.-J., Laed, R., Tito de Moraise, L., Moreaua, J.,2006. Comparative analysis of trophic structure and interactions of two tropicallagoons. Ecological Modelling 197, 461–477.

Wallentinus, I., 1991. The Baltic Sea gradient. In: Mathisen, A.C., Nienhuis, P.H.(Eds.), Intertidal and Littoral Ecosystems. In: Goodall, D.W. (Ed.), TheEcosystems of the World, vol. 24. Elsevier, Amsterdam, pp. 83–108.

Wallin, M., Hakanson, L., 1992. Morphometry and sedimentation as regulatingfactors for nutrient recycling and trophic state in coastal waters. Hydrobiologia235, 33–45.

Warzocha, J., 1994. Spatial distribution of macrofauna in Southern Baltic. Bulletin ofthe Sea Fisheries Institute Gdynia 1 (131), 48–59.

Warzocha, J., 1995. Classification and structure of macrofaunal communities in thesouthern Baltic. Archive of Fishery and Marine Research 42 (3), 225–237.

Wasmund, N., Andrushaitis, A., Lysiak-Pastuszak, E., Müller-Karulis, B., Nausch, G.,Neumann, T., Ojaveer, H., Olenina, I., Postel, L., Witek, Z., 2001. Trophic status ofthe south-eastern Baltic Sea: a comparison of coastal and open areas. Estuarine,Coastal and Shelf Science 53, 849–864.

Wilson, J.G., Parker, A., 1998. Network analysis of the energy flow through theDublin Bay ecosystem. Proceedings of the Royal Irish Academy B 98B, 179–190.

Witek, Z., 1995. Biological production and its utilisation within a marine ecosystemin The Western Gdansk Basin. Sea Fisheries Institute, Gdynia, Poland. ISBN 83-902432-3-7, pp 145 (in Polish).

Worm, B., Lotze, H.K., Sommer, U., 2000. Coastal food web structure, carbon storage,and nitrogen retention regulated by consumer pressure and nutrient loading.Limnology and Oceanography 45 (2), 339–349.

Zaika, V.E., 1983. Comparative Productivity of Hydrobionts. Kiev, Naukova Dumka,206 pp. (in Russian).

Załachowski, W., Szypuła, J., Krzykawski, S., Krzykawska, I., 1975. Feeding of somecommercial fishes in the southern region of the Baltic Sea in 1971 and 1972.Polish Archives of Hydrobiology 22, 429–448.

Zaporowski, R., 1995. Zasoby ryb i ryboluwstwo przybrzezne Zatoki Puckiej i ZatokiGdanskiej w 1995 roku. Raporty MIR.

Zydelis, R., 2001. Some remarks on effect of climatic parameters on winteringwaterbirds in the Eastern Baltic. Acta Zoologica Lituanica 11 (3), 303–308.

Zydelis, R., 2002. Habitat selection of waterbirds wintering in Lithuanian coastalzone of the Baltic Sea. Doctoral Dissertation, Institute of Ecology, VilniusUniversity, Vilnius, 138 pp.

Ozdeep, ”.A., 1988. Baltic herrings: biology and fishery (<aknbqcrbe cekmlb: <bokoubzb gpovscek). M. Aupogpovbplan. 203(2) (in Russian).

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Analysis of trophic networks and carbon flows in south-eastern Baltic coastal ecosystems