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Editorial Where we are, where we are goingThe second ‘Ecology of Stream Fish (ESF-II)’ meeting was held in Leon (Spain) on 12–16 June 2006. The meeting attracted several hundred participants and 72 papers were presented ranging from invasive species, to biodiversity regulation, to life history evolution in small populations. The first ESF, undertaken in 1998 in Luarca (Spain), was held in recognition of the tremendous progress in stream fish ecology made since 1985, when the seminal Community and Evo- lutionary Ecology of North American Stream Fishes symposium was hosted by the American Society of Ichthyologists and Herpetologists (Matthews & Heins 1987). A similar logic served as the underpinnings for the ESF-II meeting; acknowledgement that the field of stream fish ecology has progressed and perhaps shifted course slightly, in the ensuing 8 years since ESF-I. In this introduction, we will describe the similarities and differences in the two meetings and present our own, perhaps idiosyncratic views, regarding progress in the field of stream fish ecology as reflected in the contributions of the second ESF meeting. As with any active field, foci of interest can change quickly and we see evidence of that in stream fish ecology. Although there are similarities in the topical organisation of the two meetings there are differences as well, representing shifts in both basic and applied ecology. ESF-I was organised into six sections: (i) landscape approaches to stream fish ecology, (ii) life history evolution, (iii) stream management, conserva- tion and endangered species, (iv) ecological genetics, (v) mechanistic aspects of habitat selection and (6) behavioural ecology. Contributions to sections ranged from 4 to 11 presentations, and it was recognised that there was substantial overlap among sections (Rinco ´n et al. 2000). ESF-II contained the following five sections: (i) regulatory processes in populations and assemblages, (ii) landscape approaches to stream fish ecology, (iii) the importance of genetics and behaviour in ecology, (iv) ecological approaches to the conser- vation and management of stream fishes, with rele- vance to endangered species and finally, (v) life history tactics. Curiously, both more and a much broader range of papers were published in Ecology of Freshwater Fish’ from ESF-I and we are unsure why this has occurred. This is particularly puzzling, because 20 more papers were presented in ESF-II than in ESF-I (72 vs. 52). Certainly, new journals have proliferated in the past 10 years, but they probably are not enough to explain such a difference. It also is true that submission rates for ‘Ecology of Freshwater Fishhave increased substantially during this period with a concomitant increase in rejection rates. What differences do we see when examining the papers in this issue of ‘Ecology of Freshwater Fish’ as opposed to the papers from ESF-I meeting? Clearly, global climate change and invasive species have come to play a much more prominent role in stream fish ecology than they had previously. Given the energetic cost of living in a running water habitat, it is likely that the distributions of stenothermal stream fishes will contract, and those of eurythermal fishes expand, as global climate change progresses. Salmonids in the Iberian Peninsula and Cottus in southern Europe are good examples of species whose southern ranges will probably contract because of global climate change. At the same time, it is likely that cyprinids such as Squalius, Barbus and Chondrostoma will expand their ranges into the upper portions of rivers and more northern climates. Although we can hope for reversal of anthropogenic climate warming, it is likely that we should take advantage of this situation scientifically, and view this process as a potential natural experi- ment. Consequently, we may have an opportunity to gather preimpact data now, before distributional changes occur, and then be in a better position to evaluate the biological impacts on species loss addi- tion as ranges contract and expand. Such changes will not only occur in distribution (Wolter 2007), but will certainly affect the life history traits of these species as described by some contributors to the meeting (Pont et al. 2006; Gorta ´zar et al. 2007). The remaining differences between the two meet- ings involve scientific advances in science that have produced shifts in the interests of stream fish ecolo- gists, coupled with a more general acceptance of hypotheses that were still somewhat controversial in the 1990s. For example, most stream fish ecologists seem to be shifted away from the competitionist school of thought so common in the 1970s and 1980s, and now recognise that environmental variability in the form of flow and temperature variations, can depress fish populations below levels at which Ecology of Freshwater Fish 2007: 16: 465–467 Printed in Singapore All rights reserved Ó 2007 The Authors Journal compilation Ó 2007 Blackwell Munksgaard ECOLOGY OF FRESHWATER FISH doi: 10.1111/j.1600-0633.2007.00285.x 465

Where we are, where we are going…

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Editorial

Where we are, where we are going…

The second ‘Ecology of Stream Fish (ESF-II)’ meetingwas held in Leon (Spain) on 12–16 June 2006. Themeeting attracted several hundred participants and 72papers were presented ranging from invasive species,to biodiversity regulation, to life history evolution insmall populations. The first ESF, undertaken in 1998in Luarca (Spain), was held in recognition of thetremendous progress in stream fish ecology madesince 1985, when the seminal Community and Evo-lutionary Ecology of North American Stream Fishessymposium was hosted by the American Society ofIchthyologists and Herpetologists (Matthews & Heins1987). A similar logic served as the underpinnings forthe ESF-II meeting; acknowledgement that the field ofstream fish ecology has progressed and perhaps shiftedcourse slightly, in the ensuing 8 years since ESF-I.In this introduction, we will describe the similarities

and differences in the two meetings and present ourown, perhaps idiosyncratic views, regarding progressin the field of stream fish ecology as reflected in thecontributions of the second ESF meeting.As with any active field, foci of interest can change

quickly and we see evidence of that in stream fishecology. Although there are similarities in the topicalorganisation of the two meetings there are differencesas well, representing shifts in both basic and appliedecology. ESF-I was organised into six sections: (i)landscape approaches to stream fish ecology, (ii) lifehistory evolution, (iii) stream management, conserva-tion and endangered species, (iv) ecological genetics,(v) mechanistic aspects of habitat selection and (6)behavioural ecology. Contributions to sections rangedfrom 4 to 11 presentations, and it was recognised thatthere was substantial overlap among sections (Rinconet al. 2000). ESF-II contained the following fivesections: (i) regulatory processes in populations andassemblages, (ii) landscape approaches to stream fishecology, (iii) the importance of genetics and behaviourin ecology, (iv) ecological approaches to the conser-vation and management of stream fishes, with rele-vance to endangered species and finally, (v) life historytactics. Curiously, both more and a much broaderrange of papers were published in ‘Ecology ofFreshwater Fish’ from ESF-I and we are unsure whythis has occurred. This is particularly puzzling,because 20 more papers were presented in ESF-II

than in ESF-I (72 vs. 52). Certainly, new journals haveproliferated in the past 10 years, but they probably arenot enough to explain such a difference. It also is truethat submission rates for ‘Ecology of Freshwater Fish’have increased substantially during this period with aconcomitant increase in rejection rates.

What differences do we see when examining thepapers in this issue of ‘Ecology of Freshwater Fish’ asopposed to the papers from ESF-I meeting? Clearly,global climate change and invasive species have cometo play a much more prominent role in stream fishecology than they had previously. Given the energeticcost of living in a running water habitat, it is likely thatthe distributions of stenothermal stream fishes willcontract, and those of eurythermal fishes expand, asglobal climate change progresses. Salmonids in theIberian Peninsula and Cottus in southern Europe aregood examples of species whose southern ranges willprobably contract because of global climate change. Atthe same time, it is likely that cyprinids such asSqualius, Barbus and Chondrostoma will expand theirranges into the upper portions of rivers and morenorthern climates. Although we can hope for reversalof anthropogenic climate warming, it is likely that weshould take advantage of this situation scientifically,and view this process as a potential natural experi-ment. Consequently, we may have an opportunity togather preimpact data now, before distributionalchanges occur, and then be in a better position toevaluate the biological impacts on species loss ⁄ addi-tion as ranges contract and expand. Such changes willnot only occur in distribution (Wolter 2007), but willcertainly affect the life history traits of these species asdescribed by some contributors to the meeting (Pontet al. 2006; Gortazar et al. 2007).

The remaining differences between the two meet-ings involve scientific advances in science that haveproduced shifts in the interests of stream fish ecolo-gists, coupled with a more general acceptance ofhypotheses that were still somewhat controversial inthe 1990s. For example, most stream fish ecologistsseem to be shifted away from the competitionistschool of thought so common in the 1970s and 1980s,and now recognise that environmental variability inthe form of flow and temperature variations, candepress fish populations below levels at which

Ecology of Freshwater Fish 2007: 16: 465–467Printed in Singapore Æ All rights reserved

� 2007 The AuthorsJournal compilation � 2007 Blackwell Munksgaard

ECOLOGY OFFRESHWATER FISH

doi: 10.1111/j.1600-0633.2007.00285.x 465

Page 2: Where we are, where we are going…

resource limitations are important. That is not to saythat stream fish ecologists dismiss resource limitationand its spouse, interspecific competition, out of hand,but rather we now recognise that these mechanismsrequire rigorous testing before being applied to a givenstream fish assemblage. In fact, we seem to berediscovering mechanistic approaches of fish ecolo-gists of the 1950s and 1960s such as F. E. J. Fry, whoproposed that the niche could be quantified on thebasis of performance under varying physical regimesas early as the 1940s (Fry 1947). This plurality ofapproaches is good, and will help us untangle theprocesses of organising fish assemblages in streams,even if we only learn that many streams are different!

The published contributions also denote a shift frommore descriptive studies, especially those involvingassemblage dynamics to more synthetic population-based studies that frequently combine a variety ofresearch approaches to test mechanisms of populationregulation (Wootton 2007). Identification of suchmechanisms, although common in the stream salmo-nid literature, has now become a subject of study innonsalmonids, and will greatly increase our under-standing of how environmental variation and resourcelimitation affect specific populations. In addition,investigators are now focusing on factors affectingyoung-of-the-year (YOY) dynamics of stream fishes(Reichard & Jurajda 2007), a subject that has longbeen neglected because of the logistical difficulties ofquantifying YOY in running water environments.Nonetheless, changes in year class strength have beenshown to strongly affect population size in marine fishpopulations, and studies of YOY dynamics willprobably aid our understanding of population fluctu-ations and concomitant changes in assemblage struc-ture in stream fishes.

Branching out yet further, we see that substantialprogress has been made in both genetic analyses andinvasion biology and this progress is reflected in thecontributions to ESF-II (Cowley et al. 2007; Juaneset al. 2007; McPhee et al. 2007; Ribeiro et al. 2007).In the former case, it is now clear that what previouslyappeared to be homogeneous populations of speciesare actually subdivided into discrete units by eithergenetics or behaviour (or by both processes) andcannot be managed as a single demographic unit(McPhee et al. 2007). With respect to migratorysalmonids the picture is quite confusing and probablyinvolves multiple causes including the two aforemen-tioned traits combined with morphological responsesto differing natal environments (Carrier et al. 2006;McPhee et al. 2007). Several investigators have nowdocumented the importance of precocial males topopulation viability of migratory salmonids, especiallywhen population size is small (Juanes et al. 2007),whereas others have shown that microhabitat hetero-

geneity is necessary to ensure that such matings occur(Grimardias et al. 2006). In addition, the use of stableisotope analysis holds great promise in identifyingsubcomponents of a population, especially whenresident and migratory subcomponents are both pres-ent (Kristensen et al. 2006). Such studies documentthe complexity of biological processes displayed bystream fishes, and make our research efforts both moredifficult and more interesting. The study of invasivespecies also has come to prominence in the interveningyears, as we move towards a global economy withgreatly increased international commerce. Recognitionthat invasives may have negative impacts on nativefishes has been long in coming, especially given therole that fisheries agencies have had in introducingpredatory sport fish such as salmonids and centrar-chids. Added to the contribution by aquarists to theestablishment of invasives, southern Europe is nowhost to a variety of invasive cyprinids, cichlids andcentrarchids (Almeida et al. 2007; Ribeiro et al.2007). Apparently invasives tend to be most abundantin disturbed habitats (Cowley et al. 2007; Ribeiroet al. 2007) although even in these habitats they maycome into contact with native species where theireffects via many mechanisms including competition,predation and disease introduction, warrant furtherstudy given the imperative to preserve our nativefaunas.

One of the more exciting areas of applied fishecology involves the design of reserves or protectedareas that can serve not only as refuges, but also assource habitats for a broader landscape (Cucheroussetet al. 2007). The general techniques of conservationbiology dealing with the importance of reserves andreserve design have received little attention in fresh-water ecology, and hopefully this will change.

Finally, the ESF-II meeting contained a number oforal contributions dealing with advanced statisticaltechniques such as Artificial Neural Networks andindividual-based modelling (Labonne & Hendry 2006;Lasne et al. 2006), which is a welcome trend in streamfish ecology. Other methods, such Bayesian analysisand hierarchical modelling will certainly prove usefulin ascertaining habitat requirements and distributionalpatterns of stream fishes.

There were several similarities in the papers fromthe two meetings, including attempts to characterisethe dynamics of stream fish assemblages especiallywith respect to effects of both local and regionallandscape factors (Hugueny & Tadesco 2006; Gian-nico et al. 2006; Ferreira et al. 2007). In addition,stream fish ecologists continue to study both micro-habitat use and movements of stream fishes, with thegoal of delineating both population and assemblagelevel spatial boundaries and quantifying criticalhabitats. It may be some time before we come to a

Grossman & Lobon-Cervia

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consensus on topics such as the restricted movementparadigm, especially because stream fish populationsseem to display a variety of movement patterns. It islikely that microhabitat studies will be more successfulfrom both a predictive and a critical habitat perspec-tive, if they include some aspect of fitness such asenergetic cost or gain.Rapid progress continues to be made in the field of

stream fish ecology and the organisers hope that thisvolume helps fill the informational needs of both basicand applied fish ecologists.

G. D. Grossman1, J. Lobon-Cervia21Warnell School of Forestry & Natural Resources.University of Georgia, Athens, GA, USA,2National Museum of Natural Sciences (CSIC)C ⁄ Jose Gutierrez Abascal, Madrid, Spain

Acknowledgements

The organisational skills of Gustavo ‘Gus’ Gonzalez, EvaAlvarez, David Perez, David Mıguelez and our translator MsMaite Lavandeira were the essentials of this meeting. Warmthanks are due to the staff of the Universidad de Leon andparticularly to Jose Carlos Pena (School of Biological Sci-ences), and to the Diputacion y Ayuntamiento de Leon andConsejeria de Medio Ambiente de Castilla y Leon for all theirhelp and support.

References

Almeida, D., Nicola, G.G., Almodovar, A. & Elvira, B. 2007.Risk of spread of exotic largemouth bass Microterussalmoides & pumpkinseed Lepomis gibbosus in Park,Cabanero Nacional. An approach from trophic ecology.Ecology of Stream Fish II, Abstract. Leon, Spain.

Carrier, A., Dodson, J. & Guderley, H. 2006. The influence ofwater velocity in the determination of anadromy or residencyin brook charr (Salvelinus fontinalis). Ecology of Stream FishII, Abstract. Leon, Spain.

Cowley, D., Wissmar, R. & Sallenave, R. 2007. Fish assem-blages and seasonal movements of fish in irrigation canalsand river reaches of the middle Rio Grande, New Mexico(USA). Ecology of Freshwater Fish 16: 548–558.

Cucherousset, J., Paillisson, J.-M., Carpentier, A., Thoby, V.,Damien, J.-P., Eybert, M.-C., Feunteun, E. & Robinet, T.2007. Freshwater protected areas: an effective measure toreconcile conservation and exploitation of the threatenedEuropean eels (Anguilla anguilla)? Ecology of FreshwaterFish 16: 528–538.

Ferreira, M., Sousa, L., Santos, J., Reino, L., Oliveira, J.,Almeida, P. & Cortes, R. 2007. Regional and local environ-mental correlates of native Iberian fish fauna. Ecology ofFreshwater Fish 16: 504–514.

Fry, F. 1947. Effect of the environment on animal activity.University of Toronto Studies, Biological Series, No. 54,Publications of Ontario Fisheries Research Laboratory, No.68. Toronto, Canada.

Giannico, G., Boxall, G. & Li, H. 2006. Can topography beused to predict Lahontan cutthroat trout distribution inheadwater stream reaches. Ecology of Stream Fish II,Abstract. Leon, Spain.

Gortazar, J., Garcia de Jalon, D.l., Alonso-Gonzales, C., Vizca-ino, P., Baeza, D.&Marchamalo,M. 2007. Spawning period ofa southern brown trout population in a highly unpredictablestream. Ecology of Freshwater Fish 16: 515–527.

Grimardias, D., Chebaud, J., Merchermek, N. & Beall, E. 2006.The importance of habitat diversity on the reproductivesuccess of precociously mature male parr of Atlantic Salmon.Ecology of Stream Fish II, Abstract. Leon, Spain.

Hugueny, B. & Tadesco, P. 2006. Landscape filters and speciestraits: a test of life-history theory for west African river fishes.Ecology of Stream Fish II, Abstract. Leon, Spain.

Juanes, F., Perez, J. & Garcia-Vazquez, E. 2007. Reproductivestrategies in small populations: using Atlantic salmon as acase study. Ecology of Freshwater Fish 16: 468–475.

Kristensen, E., Closs, G. & Kim, J. 2006. Estimating thereproductive contribution of sympatric resident and migratorybrown trout (Salmo trutta) on a longitudinal scale in smallspawning tributaries: effects on population dynamics. Ecol-ogy of Stream Fish II, Abstract. Leon, Spain.

Labonne, J. & Hendry, A. 2006. Interactions between gene flowand adaptive divergence in populations of guppies (Poeciliareticulata): an individual based modeling approach. Ecologyof Stream Fish II, Abstract. Leon, Spain.

Lasne, E., Lek, S. & Laffaille, P. 2006. Hierarchical manage-ment of floodplain fish biodiversity: a species-basedapproach. Ecology of Stream Fish II, Abstract. Leon, Spain.

Matthews, W. & Heins, D. 1987. Community and evolutionaryecology of North American stream fishes. Norman, OK:University Oklahoma Press.

McPhee, M., Utter, F., Stanford, J., Kuzishchin, K., Savvaitova,K., Pavlov, D. & Allendorf, F. 2007. Population structure andpartial anadromy in Oncorhynchus mykiss from Kamchatka:relevance for conservation strategies around the Pacific Rim.Ecology of Freshwater Fish 16: 539–547.

Pont, D., Abdoli, A., Sagnes, P., Reyjol, Y., Crane, R. &Hugueny, B. 2006. Global warming, geographical distribu-tion and life history strategy of the bullhead (Cottos, gobio).Ecology of Stream Fish II, Leon, Spain.

Reichard, M. & Jurajda, P. 2007. Seasonal dynamics and agestructure of drifting cyprinid fishes: an interspecific compar-ison. Ecology of Freshwater Fish 16: 482–492.

Ribeiro, F., Orjuela, R., Megalhaes, M. & Collares-Pereira, M.2007. Variability in feeding ecology of a South Americancichlid: a reason for successful invasion in Mediterranean-type rivers? Ecology of Freshwater Fish 16: 559–569.

Rincon, P.A., Hughes, N.F. & Grossman, G.D. 2000. Land-scape approaches to stream fish ecology, mechanistic aspectsof habitat selection and behavioral ecology. Introduction andcommentary. Ecology of Freshwater Fish 9: 1–3.

Wolter, Ch. 2007. Temperature influence on the fish assemblagestructure in a large lowland river, the lower Oder River,Germany. Ecology of Freshwater Fish 16: 493–503.

Wootton, R.J. 2007. Over-wintering growth and losses in asmall population of the threespine stickleback, Gasterosteusaculeatus (L.), in mid-Wales. Ecology of Freshwater Fish 16:476–481.

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