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1 PROGRESS REPORT 1 st SEMESTER (JANUARY – JULY 2014) THE ASSESSMENT ON BLUE SWIMMING CRABS (Portunus pelagicus (Linnaeus, 1758)) FISHERIES IN NORTH COAST OF JAVA Research Center for Fisheries Manageent and Conservation (RCFMC) Jl. Pasir Putih 1, Ancol Timur, Jakarta-14430 for Indonesia Blue Swimming Crab Processors Association (APRI) Jl. KIG Raya Selatan Kav C-5, Gresik, Jawa Timur, Indonesia BACKGROUND Crab fishery has contributed as one of the source livelihood of small-scale fishers in the North of Java since the 1970s and still exist seasonally until to date. An intensive fishing increased since the 1990s, this along with increasing international market demand (FAO, 2013). Blue swimming Crabs (Portunus pelagicus Linnaeus, 1758) is economic important marine living resources in Indonesian, it ranked under tuna and shrimps. Kailola et al. (1993) and Ng (1998) stated that this species widely distributed in Indo-Pacific waters, West Indian and East Pacific Oceans. Sumiono (1997) and Sumiono et al. (2011) informed that Blue swimming Crabs in Indonesia distributed along the coastal area of east Sumatera, north of Java, South of Sulawesi, South and East Kalimantan. Among them, Jakarta and Cirebon Bays, Brebes, Rembang and Madura strait were the main fishing areas in the north coast of Java. Antara News (1989) informed that several species of swimming Crabs in Indonesia, Portunus pelagicus is the highest export value species in form of picking, cooking, frozen or caning. The estimate export volume in 2012 is around 28,000 tons, which is commercially valued at around 330 million USD (Fauzi, 2013). FAO (2011) in Chu et al., (2012) mentioned that Indonesian annual production fluctuated during period of 1970 to 2008. The annual production in 2008 estimated at around 34,000 tons and it contributed 20% of world production after China. Worldwide policy on sustaining fish for food (including blue swimming crabs) should consider safety, security and sustainability

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Page 1: PROGRESS REPORT 1st SEMESTER (JANUARY – JULY 2014) … · 1 ! PROGRESS REPORT 1st SEMESTER (JANUARY – JULY 2014) THE ASSESSMENT ON BLUE SWIMMING CRABS (Portunus pelagicus (Linnaeus,

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PROGRESS REPORT 1st SEMESTER (JANUARY – JULY 2014)

THE ASSESSMENT ON BLUE SWIMMING CRABS (Portunus pelagicus (Linnaeus, 1758)) FISHERIES IN NORTH COAST OF JAVA

Research Center for Fisheries Manageent and Conservation (RCFMC)

Jl. Pasir Putih 1, Ancol Timur, Jakarta-14430

for

Indonesia Blue Swimming Crab Processors Association (APRI) Jl. KIG Raya Selatan Kav C-5, Gresik, Jawa Timur, Indonesia

BACKGROUND • Crab fishery has contributed as one of the source livelihood of small-scale fishers in the

North of Java since the 1970s and still exist seasonally until to date. An intensive

fishing increased since the 1990s, this along with increasing international market

demand (FAO, 2013).

• Blue swimming Crabs (Portunus pelagicus Linnaeus, 1758) is economic important

marine living resources in Indonesian, it ranked under tuna and shrimps. Kailola et al.

(1993) and Ng (1998) stated that this species widely distributed in Indo-Pacific waters,

West Indian and East Pacific Oceans. Sumiono (1997) and Sumiono et al. (2011)

informed that Blue swimming Crabs in Indonesia distributed along the coastal area of

east Sumatera, north of Java, South of Sulawesi, South and East Kalimantan. Among

them, Jakarta and Cirebon Bays, Brebes, Rembang and Madura strait were the main

fishing areas in the north coast of Java.

• Antara News (1989) informed that several species of swimming Crabs in Indonesia,

Portunus pelagicus is the highest export value species in form of picking, cooking,

frozen or caning. The estimate export volume in 2012 is around 28,000 tons, which is

commercially valued at around 330 million USD (Fauzi, 2013). FAO (2011) in Chu et

al., (2012) mentioned that Indonesian annual production fluctuated during period of

1970 to 2008.

• The annual production in 2008 estimated at around 34,000 tons and it contributed 20%

of world production after China. Worldwide policy on sustaining fish for food

(including blue swimming crabs) should consider safety, security and sustainability

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issues of its resources. Wall Mart, Costco Wholesale, Sam’s Club Whole Foods

Market and others (Crawford, 2013) adopted those mainstreams of world market

system. By 2020, it is expected that world buyers on fish product will only accept

products that have been eco-labeling certified issued by the Marine Stewardship

Council (MSC). There are wide spread informations available on the benefit of applied

best practices sustainable fisheries and its management plan. This ecolabelling

certification voluntarily proposed regarding issues on Fisheries Improvement Project.

• The annual world statistics on blue swimming crab production and within the last 5

years Indonesian (IDN) contribution were around 20%. (Figure 1)

0

20

40

60

80

100

120

140

160

180

200

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

ESTIMAT

ED  LAN

DING

 (x  100

0  TO

NS)

WORLD

IDN

Figure 1 The annual world and national landing of blue swimming crabs 1970 – 2012

Source : http://www.fao.org/fishery/species/2629/en 16 November 2014

• Since 2014, RCFMC and APRI carried out a Blue swimming crab fisheries assessment

in the north coast of Java. Observation was carried out through collecting the

dependent and independent fisheries data.

OBJECTIVES

The objective of research project is to provide the present status of blue swimming

crabs fisheries in the Java Sea as a base line information on designing Harvest Control

Rules to support its Fisheries Management Plan.

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METHODS

Site locations Six site locations were selected as a major data base to collect the data. There are

distribute along the coast of north of Java and South of Kalimantan (Figure 2). Each

location has a different characteristics on fishing gear and its tactic and strategy on BSC

exploitation.

Figure 2. Site locations

Data collecting There are two types of data were proposed to collect during this research project.

First, dependent data on fisheries through regular weekly sampling in representative sites,

miniplant and collectors in the several landing bases i.e Jakarta, Cirebon, Demak,

Rembang, Sumenep (North coast of Jawa) and Sampit (South coast of Kalimantan) and it

consisted of length frequency, catch by type of gear, and effort characteristics. Secondly,

independent data through onboard sampling in a small-scale commercial fishing vessels

measuring size and catch compotition by gear by depth distribution, ecological related

species and possibly the occurrence of ETP species. Observation on oceanographic

parameters i.e. salinity, temperature and bottom substrate profiles and larval abundance.

Data Analysis

A simple model for tropical fish stock assessment will be applied on data analysis.

Several approach to describe stock status and its perspectives including production and

analytical model were used based on size, catch and effort data.

Java  Sea  

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Biological aspects Length – weight relationships

Length weight relationship was analyszed through carapace length and weight of

specimens. Regression analysis followed the formula of King (1995):

which :

W = weight (gram) a = (slope) L = carapace length (mm), b = constant

Average size at first maturity (Lm)

Size at first maturity, were estimated through a formula of King (1995)

Remarks:

PLm : proportion of size of specimen mature to immature, a and b : parameters.

Average length at first capture (Lc)

Length at first capture (Lc) by type of gear (collapsible trap, gillnet, trawl) were

calculated through selectivity approach on logictics function (Stewart & Ferrel, 2002). The

formula were as follows:

Remarks: r(l) = probalility retention l = carapace width a & b = constant

Biomass estimation from on board commercial fishing vessel

Stock density were calculated by using swept area method for mini bottom trawl,

(Saeger et al., 1976), with a formula of:

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Remarks:

D = stock density (kg/ km2) C/t = catch per hour (kg/jam) a = area swept by gear

e = escapement factor = 0,5 (Saeger et al., 1980 dalam Sparre & Venema, 1999)

v = vessel speed (knot) h = head rope length (m)

E = head rope opening = 0.5 (Pauly,1980 dalam Sparre & Venema, 1999)

1,852 = conversion mile to km 1.000 = conversion from meter to km Biomass estimation will be calculated by using a classic equation as follows :

B = D x A

Remarks:

B = biomassa (kg) D = stock density (kg/km2) A = area covered (km2) A general fishing power index will be determined based on catch by type of gear used and its characteristics to fish BSC. Spawning potential ration (SPR)

SPR can be calculated for different levels of Lc and F by dividing spawning stock

biomass under exploitation ( ) by pristine spawning stock biomass ( )

SSBF = existing spawning stock biomass SSBF=0 = pre fishing spawning stock biomass

Biomass calculated at each time-age class and spawning stock biomass is simply

the sum of all biomass above the age at maturity. Spawning stock biomass is calculated as:

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Wt = the average weight by age at spawn Nt = estimate number of fish by age at spawn Population parameters as an input to this model consisted of:

- Natural Mortalitas (M) - Growth parameters (K, L∞, to) - Regression coefficient (a, b) - Length at first maturity (Lm)

Surplus Production Model

A schaeffer model will be applied to estimate a maximum sustainable yield and its

optimum efforts. An appropriate Harvest Control Rule will be applied to initiate

management measures.

WORKPLAN AND ACHIEVEMENTS

The general scheme on research project

The steps and process of the activities on data collecting, validation and the way to

analyze data were shown in Figure 3. It consisted of several steps from source of data, type

of data measured and observed, preliminary analysis due to on going regular sampling

program and limited on board observation in two main locations. Advance analysis and

draft final report will be carried out in January 2015. Focus group discussion will be

proosed to held in the end of February 2015.

Initiative Performance Indicators of research project

The performance indicators of on going research project were mapped in Figure 4.

Scope of work including data collecting system, data collecting system, type of data,

location, platform and time line were identified and listed. The predicted achievement

level as major research performance indicators showed that there are still items with less of

50% (red). The major component of low indicators is due to data still in hard copies and

some of them still on going process including some amandmend on additional two

locations proposed during the last midterm evaluation.

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Fishery  dependent:• landings• enumerator• sampling

Fishery  independent   (at  sea  research):• Charterd  

Fishing  Boats

• Biological  data• Catch• Effort

• Catch  composition

• Biological  data• Catch  composition

• By-­‐catch• Catch-­‐rate• Larva• Habitats

•Population parameters(L∞,K,to, Z,M,F,E)• Lm• Lc•Indices of stock abundance& recruitment•Est.Biomass & SSB•MSY•Genetic population•Mapping life cycle

Harvest  control  rule

Stock  assesment

FISHERY  MANAGEMENT  AREA Harvest  Strategy

Figure 3. General frame work of BSC research project

Field  survey  

  Draft  Report

Dissemination 2nd  phase

2014 National   Provincial   District Crb Dmk Rbg Sum Sam Pas JaB Crb DmkJanuary x x x xFebruary x x x xMarch x x x x xApril x x x x xMay x x x xJune x x x xJuly x x x x x x xAugust x x x x xSept x x x x xOctober x x x x x x mid  November x x x x xDecember x x x x x x x x x

January Final  February FGD

expected  output

Estimated  MSY,    fopt,  

CPUE  Fishing  Power  Index  

annual  fluctuation

seasonal  variabil ity

data  validatio

n  

data  processing

on  going done

Achievement  (%)

80 10 10 100 0 0 60 60 60

Remarks  : Cr  =  Cirebon Pas  =  PasuruanL/W  =  length  weight  relation  ship Dm  =  Demak JaB  =  Jakarta  BayLm  =  estimated  size  at  first  mature Rb  =  RembangLc    =  estimated  size  at  first  capture Sum  =  SumenepCPUE  =  Catch  per  unit  of  effort Sam  =  SampitMSY  =  Maximum  sustainable  Yieldf  opt  =  optimum  effort

proposal  2015  -­‐2016

60

on  schedule

Bio  -­‐reproduction  (Sex  ratio,  Maturity,  L/W,  Lm  and  Lc,  

growth  parameters,  mortality,  Exploitation  

rates,  SPR,  PSA

on  going

esti  Bo  ,  S  &  T  profi le,  

Substrate,  Larvae,  Gear  Selectivity

historical  annual  data  2000  -­‐  2012  catch  and  estimated  effort

Statistic  on  capture  fisheries

quarterly  within  last  5  years  data  

monthly  within  last  5  years  data  on  catch  and  effort  by  gears  

Enumerators on-­‐board

Figure 4. Workplan and its on going achievement

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PRELIMINARY RESULTS

Landing site observation Since January 2014, local trained enumerators established to measure the biological

aspects such as carapace length, weight, sex and maturity stages. Validating processes

were done in March and July 2014. Fisheries data consisted of catch per trip by gear,

fishing ground were also collected from local fishers through interviewing.

• Three type of fishing gear were used during survey, they are mini bottom trawl,

collapsible trap and bottom gillnet.

Fisheries data • Data consisted of gear description, catch rate and its composition, fishing areas.

Information on environmental condition on substrate, depth, salinity, temperature,

dissolved oxygen and crabs larvae also observed.

• Field identification blue swimming crabs species referred to Ng (1998) and Sumpton et

al. (1994). Fischer & Whitehead (1974); Gloerfelt-Tarp & Kailola (1985); Nakabo

(2000); Carpenter & Volker (1998) were used for fish specimens.

Fishing Gears Bottom gillnet

Length of net (bottom gill net) with maximum 7.000-8.000 meters. It made by

monofilament with mesh size of 3.5” (Figure 3). Fishing operation during dark period and

deployed at midnite for 4 to 5 hours depends on the catch.

Collapsible trap

Fishing vessels with length of 6 – 10 m, breadth 1,5–2,8 m and depth of 0,75–1,5

m. Inboard engine of 16 - 25 PK. Two fish hold covered by fibre with 90 x 60 x 70 cm

sebanyak 2 buah). Number of crew 5 persons. Traps were made by combination of wire

and polyethylene D6. The dimension of 18 cm height, 25 cm width and 40 cm length.

Mouth opening 6-8 cm (Figure 4). Number of traps by trip during sampling was 750 unit.

Dredge net

Dredge net is the active fishing gear. Length of mouth is 2 meter with height of 1,5

meter. Webbing made by PE-multifilamen with mesh size of 0.75-inch dengan ukuran

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mata in codend is 0.75-inch (Figure 5). Towing at around 1 – 2 hours with speed 0f 1 – 2

knots

Demersal Danish seine

Jaring arad as of one type of demersal Danish seine is used to target shrimps

resource operated with fishing craft of < 5GT. Otter board with size of 40 cm x 80 cm and

thikness 2 cm. Length of wing part at around is 11,2 meter with mesh size at around 24-45

mm, cod end of 1.7 m

Research findings

Biological aspects

• The carapace width frequency distribution in two main locations of Demak and

Rembang (Central Java) showed that the higher average was found in the collapsible

traps. The catch from demersal Danish seine was the lowest average. Gill net mostly

between Danish seine and collapsible trap.

Figure 5. Carapace width distribution by type of gear and locations (januari – August

2014)

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• The range of carapace width measurement from enumerators were preliminary

indicate that the largest mean by sex occurred in the specimens from Sampit of

south Kalimantan. The smallest mean came from Cirebon west Java (Table 1). This

probably strongly related to relatively healthy habitat and environmental condition

in the area compared to north coast of Java.

Table 1. Minimum, Maximum and mean of carapace width based on enumeration by site

location.

Location Carapace width (mm)

Male Female min max. mean min max mean Cirebon 85,7 146,8 110,0±14,7 72,2 143,3 110,7±18,3 Demak 68,7 168,4 115,3±18,8 59,2 161,9 116,8±18,6 Rembang 70,4 159,2 117,1±15,5 79,0 165,6 117,8±15,8 Sumenep 85,4 147,1 111,8±14,9 77,7 143,8 112,0±18,1 Sampit 87,0 165,0 135,0±14,7 90,0 183,0 130,0±13,8

• The mean carapace width bysex by three types of fishing gear were also observed

and it showed that the largest mean found in specimens caught by collapsible traps.

The smallest size occurred in specimens caught by mini bottom trawl or demersal

Danish seine (Table 2).

Table 2. Mean carapace width by sex, location and type of gear

Gears Mean of carapace width (mm)

Demak Rembang Male Female Male Female

Mini bottom trawl 102,1+15,6 103,9+15,8 Gillnet 102,6+14,7 107,1+13,2 116,9+16,0 110,7+15,6

Collapsible trap 122,1+17,1 124,3+16,8 117,7+15,0 118,8+15,6

• Estimation on length at first maturity (Lm) and length of fisrt capture (Lc) were

also calculated based on specimens measured by site locations. The preliminary

assessment indicated that the highest Lm and Lc occurred in Sampit south

Kalimantan. The smallest values occurred in specimens measured in Cirebon

(Table 3).

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Table 3. Estimated Lm and Lc by locations

Lokasi Lm (mm) Lc (mm) Cirebon 98.12 116.19 Demak 112.47 115.55 Rembang 101.51 116.58 Sumenep 100.06 111.68 Sampit 126.78 129.50

Rata2 107.79 117.90 Std. Dev. 11.99 6.77

Length weight relationship

• Length weight relationships between male and female were different. B coefficient

of male is always higher than male (Figure 6).

y  =  8E-­‐06x3.4489R²  =  0.8372

n=295

0

50

100

150

200

250

0 20 40 60 80 100 120 140 160

W  (gr)

CW  (mm)

y  =  2E-­‐05x3.2597R²  =  0.8878

n=123

0

50

100

150

200

250

300

0 50 100 150 200

W  (gr)

CW  (mm)

y  =  9E-­‐06x3.4512R²  =  0.9544

0200400600

0 50 100 150 200

W(gram)

CW (mm)

Demak

y  =  2E-­‐05x3.2602R²  =  0.9219

-­‐150

50

250

450

0 50 100 150 200

W(gram)

CW (mm)

Demak

W=  1E-­‐05L3,385R²  =  0,941

0

200

400

0 50 100 150 200

W  (gram)

CW  (mm)

Rembang

W=  3E-­‐05L3,191R²  =  0,927

0

200

400

0 50 100 150 200

W(gram)

CW (mm)

Rembang

y  =  1E-­‐05x3,404R²  =  0,910

0200400600

0 50 100 150 200

W(gram)

CW  (mm)

Sampit

y  =  6E-­‐05x3,036R²  =  0,878

0200400600

0 50 100 150 200

W(gram)

CW  (mm)

Sampit

Cirebon  Cirebon  Cirebon   Cirebon  

Figure 6 . Carapace width and weight relationships between male and female based on data

from Cirebon, Demak, Rembang dan Sampit

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• Length at first maturity

Preliminary analysis on estimated length at first maturity were found at around

100.8 cm CW. It seems all the catch were above this value (Figure 7).

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Figure 7. Estimated length at first mature and length at first capture by locations

Spawning Potential Ratio (SPR)

• SPR is an one of recent reference point could applied for fisheries management and

its measures. Literature study explain that across a broad range of species, a

threshold of 40% SPR is generally accepted as a proxy for Maximum Sustainable

Yield (MSY) and 50% SPR is generally accepted as a proxy for Maximum

Economic Yield (MEY) of a certain fisheries. Situation of stocks are generally

thought to risk recruitment of its stocks is declining when the level of SPR < 20%.

The preliminary exploration on limited data that has been collected showed that the

stocks is relatively not in risk condition (Figure 8).

Figure 8. The estimated Spawning Potential Ratio of BSC

Onboard data collection • Observation on research data through onboard sampling using several types of small

scale fishing gear has been carry out during this first semester. Coastal water of

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Cirebon and Demak north coast of central Java (Figure 1) were selected as the area to

study.

• First survey was carried out in Cirebon on July 2014. A number of 14 trawl sampling

stations (Figure 9), including 9 stations were collected. The geographical location of

fishing activities by type of gear were showed in Figure 10. Distribution of fishing

station and catch rates by Danish seine (Figure 11), dredge net (Figure 12)

108.4°E 108.45°E 108.5°E 108.55°E 108.6°E 108.65°E 108.7°E 108.75°E 108.8°E 108.85°E 108.9°E-6.9°S

-6.85°S

-6.8°S

-6.75°S

-6.7°S

-6.65°S

-6.6°S

-6.55°S

-6.5°S

-6.45°S

-6.4°S

12

3 4 5

6

789

10

11

12

13

14

Gebang

CIREBON

Figure 9. Oceanographic Sampling stations on July 2014.

Figure 10. The sampling fishing area by gill net, dredge and demersal Danish seine.

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Figure 11. Distribution of fishing station of demersal danish seine and its catch rates in

Cirebon, Juli 2014

Figure 12. Fishing stations by dredge net and its catch rates in Cirebon, Juli 2014

Ecological Related Species

• Issues on the ecological related species is one of the information to measure the

ecosystem impact of fisheries activities. The List of ecological related species of

BSC fisheries were slightly different by type of gear. This occurred due to the

technical efficiency and performance of the gear. Specific analysis will be held on

108.4°E 108.45°E 108.5°E 108.55°E 108.6°E 108.65°E 108.7°E 108.75°E 108.8°E 108.85°E 108.9°E-6.9°S

-6.85°S

-6.8°S

-6.75°S

-6.7°S

-6.65°S

-6.6°S

-6.55°S

-6.5°S

-6.45°S

-6.4°S

Gebang

CIREBON

Tangkapan Ikan Demersal (kg)

0.475 to 1.34 1.34 to 1.992 1.992 to 4.13 4.13 to 5.511

Remarks:     100,472  -­‐  149,07  kg/km2      

90,85  kg/km2  

 

  42,045  kg/km2  

Gebang

Java  Sea  

J  ava  Sea  

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after survey completed. The list of species and its composition by four type of

fishing gear used by fishers were showed in Figure 13, 14 and 15.

Gill net

Figure 13. Catch composition of ecological related species caught by gill net

Dredge net

Figure 14. Catch composition of ecological related species caught by dredge net in Cirebon

2014

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Demersal Danish seine

Figure 15. Catch composition of ecological related species caught by demersal dansih

seine net in Cirebon 2014

Estimated density

• The catch rates of BSC during fishing with demersal Danish seine were showed in

Table 4. The estimate density ranged between 42 to 159 kg/km2, the value is

relatively high compare the actual fishers estimates. Some detail data exploration

will be held after the last on-board observation were completed.

Table 4. Catch rate and stock density of BSC caught by Danish seine in Cirebon waters,

July 2014.

No Latitude Longitude Setting

time (hr)

Total catch (kg)

Catch rate (kg/hr)

Stock density

(kg/km2) 1 6046,305' 108044,305' 0.75 100.47 133.96 100.47 2 6046,724' 108045,090' 0.83 42.04 50.45 42.04 3 6045,649' 108044,303' 0.83 nd nd nd 4 6045,657' 108044,111' 0.92 104.23 113.71 104.23 5 6046,584' 108043,342' 0.47 90.85 194.68 90.85 6 6047,167' 108043,558' 0.47 149.07 319.44 149.07

Total 4.27 486.67 812.24 486.67 Average 0.71 81.11 135.37 81.11

Nd= unsuccessful haul

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Oceanographic Parameters

• Oceanographic stations were collected simultaneously before or after trawl

sampling. The parameter consisted of temperature, salinity, dissolved oxygen and

measured by using water quality checker tipe WQC 22A. Substrate and

macrobenthic were collected by using grab bottom sampler of 20x20 cm or 0.04

m2. A bongo net were used to collect crab larvae. Substrate were observed by using

Millar triangle to obtain sand, dust and dan clay (Brower et al., 1990).

• The physical water body and substrate characteristics were listed in Table 5 and 6.

Futher analysis will be carried out after completed the second surveys at different

monsoon.

Table 5 . Data on oceanographic parameter survey in Cirebon and adjacent waters, July 2014

Depth Transparency(m) (m) Surface Bottom Surface Bottom Surface Bottom Surface Bottom

1 -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐2 9 6 28.3 28.2 32 32 5.9 6 6.3 5.3 Muddy3 7 6 28.5 28.1 32 32 7 6.1 6.9 6.8 Muddy4 7 2 29 28.7 31 32.5 6.6 6.4 6.4 6.5 Muddy5 8 2 29.5 29 30 31 6 5.9 6.3 6.4 Muddy6 6 0 28.2 27.9 31 31 7 6.7 6.8 7.6 Muddy7 2 0.5 28 28 29 29 7 7 7.3 7.3 Muddy8 -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐9 -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐10 9 2.5 29.2 28.6 30 30 7.3 7.4 6.6 7.3 Muddy11 -­‐ -­‐12 8 3 28.3 28.2 31 32 5.5 6.6 8.6 8.7 Muddy13 -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐ -­‐

Sta.  No.pHWater  temp  (oC) DO  (ppm)Salinity  (‰) Substrate  type

Remarks: - no data vailable

Table 6. Subtrate type in Cirebon and adjacent waters, July 2014

No. No. Sta. Substrate texture (%) Substrat type Sand Dust Mud

1 1 3.52 0.50 95.98 Muddy 2 2 4.02 1.51 94.47 Muddy 3 3 5.53 1.01 93.47 Muddy 4 4 4.02 1.51 94.47 Muddy 5 5 3.02 1.01 95.98 Muddy 6 6 3.02 1.01 95.98 Muddy 7 7 3.02 10.05 86.93 Muddy 8 10 4.02 0.50 95.48 Muddy 9 11 2.51 1.01 96.48 Muddy

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Larval Abundance

• Preliminary analysis on occurrence of predicted BSC larvae were listed in

Table 7. It showed that the maegalopa were mostly found in Station No. 10

and 11 which geographically located to near shore around mangroves.

Table 7. The estimate of BSC larval abundance in Cirebon and adjacent waters, July 2014

Stadia Est. abundance (ind./m3) St. 1 St. 2 St. 3 St. 4 St. 5 St. 6 St. 7 St. 10 St. 11

Zoea 1 1873 2548 573 2675 2956 15 19 96 3121 Zoea 2 420 204 541 1376 892 15 42 96 1847 Zoea 3 204 127 319 255 25 15 31 32 1147 Zoea 4 51 0 64 51 0 10 11 32 382

Megalopa 0 0 0 0 0 0 0 32 32 REFERENCES Brower, J.E., J.H. Zar & C.N.V. Ende. 1990. Field and laboratory method for general

ecology. Third edition. Wm.C.Brown Publisher. Dubuque. Iowa: 40-120 Carpenter,K.E & H.N.Volker (Eds). 1998. The Living Marine Resources of the Western

Central Pacific. Vol. 2. Cephalopods, Crustaceans, Holothurians and Sharks. FAO, Rome, Italy

Gloerfelt-Tarp, T. & P. Kailola. 1985. Trawled fish of the southern Indonesia and northern Australia. ADAB –GTZ-DGF Indonesia : xvi + 406 p.

Fischler, KJ & C.H Walburg. 1962. Blue crab movement in coastal South Carolina, 1958-59. Trans. Am.Fish. Soc. 91:275-278.

Fischer,W & P.J.P. Whitehead, 1974. FAO Species Identification Sheets for Fishery Purposes. Eastern Indian Ocean and Western Central Pacific. FAO-UN Rome.

Nakabo, T., 2000. Fishes of Japan with pictorial keys to the species. Second Edition. Tokai University Press. 2-28-4, Tomigaya, Shibuya-ku, Tokyo.

Ng PKL. 1998. Crabs. In Carpenter, K.E. & V.H.Niem (Eds.). FAO Species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. FAO-UN. Vol. 2. Rome :1045 - 1155.

Ravi R & M.K Manisseri. 2012. Survival Rate and Development Period of the Larvae of Portunus pelagicus (Decapoda, Brachyura, Portunidae) in Relation to Temperature and Salinity. FAJ(49):1-8.

Smith H. 1982. Blue Swimmer Crabs in South Australia – their Status, Potential and Biology. Safic. 6(5):6-9.

Sumpton,W.D., M.A. Potter & G.S.Smith. 1994. Reproduction and Growth of the Commercial Sand Crab, Portunus pelagicus (Linn.) in Moreton Bay, Queensland. Asian Fish.Sci. (7): 103-113.

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APPENDIX 1. Larvae of BSC (stadia zoea 1, zoea 2, zoea 3, zoea 4 and megalopa) caught in Cirebon and adjacent waters, July 2014