Kajian penangkanapan udang putih kecil sebagai aplikasi pengelolaan di muara Sungai Kakap Kabupaten Pontianak Kalimantan Barat
STUDY ON CAPTURE OF SMALL WHITE SHRIMP (
Metapenaeus
lysianassa,
de Man 1888
)
AS A MANAGEMENT APPLICATION IN
SUNGAI KAKAP ESTUARY KABUPATEN PONTIANAK
WEST KALIMANTAN
SAPTOYO
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
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THESIS STATEMENT AND SOURCE OF INFORMATION
Hereby I declare that thesis Study on Capture of Small White Shrimp (
Metapenaeus
lysianssa,
de Man 1888) as A Management Application in Sungai Kakap Estuary
Kabupaten Pontianak West Kalimantan is my own research and the thesis is not proposed
and published in other universities yet. The sources of information quoted from other
authors were mentioned in the text and in the references of this thesis.
Bogor, September 2006
SAPTOYO
NRP. C251040374
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ABSTRACK
SAPTOYO. Study on capture of small white shrimp (
Metapenaeus lysianassa,
de Man
1888) as A Management Application in Sungai Kakap estuary Kabupaten Pontianak West
Kalimantan. Under supervision of YUSLI WARDIATNO, UNGGUL AKTANI and
SULISTIONO.
Small white shrimp (
Metapenaeus lysisanassa
) fishery using setnets in Sungai
Kakap estuary increased from the year 1994 to 2005 and this sector gave a lot of benefit for
fishermen. The advantages of this shrimp fishery are providing work and income for local
people, providing of nutritious food for human life and local government income from tax
or retribution. However, the increasing fishermen effort to catch small white shrimp in this
estuary is estimated to be followed by decreasing of their productivities and declining of
CPUE trend. The objectives of the study are to obtain distribution pattern of small white
shrimp caught by setnet and to obtain CPUE (Catch per Unit Effort) trend of small white
shrimp fishery. Eleven stations were established in this site to learn distribution pattern of
small white shrimp caught by setnet and time series data of catch and effort was used to
calculate the trend of CPUE. The study got information that distribution pattern of small
white shrimp was caught in higher numbers in salinity interval 5 – 7‰. Bigger sizes of
small white shrimp were found in salinity 10 - 20‰. CPUE of small white shrimp caught
by setnet tends to decrease during twelve years.The study result is expected to give
information for management plan to manage of small white shrimp fishery.
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ABSTRAK
SAPTOYO.
Kajian penangkanapan udang putih kecil (
Metapenaeus lysianassa,
de Man
1888) sebagai aplikasi pengelolaan di muara Sungai Kakap Kabupaten Pontianak
Kalimantan Barat. Dibimbing oleh YUSLI WARDIATNO,
UNGGUL AKTANI dan
SULISTIONO.
Perikanan udang putih kecil (
Metapenaeus lisianassa
) menggunakan setnet di
muara Sungai Kakap telah mengalami perkembangan sejak tahun 1994 hingga 2005 dan
sektor ini telah memberikan banyak manfaat bagi nelayan. Manfaat yang diperoleh antara
lain adalah penyediaan lapangan pekerjaan dan pendapatan bagi masyarakat setempat,
penyediaan protein hewani dan pajak atau retribusi untuk pemerintah daerah. Akan tetapi
peningkatan upaya yang dilakukakan nelayan untuk menangkap spesies udang putih kecil
diperkirakan telah menyebabkan terjadinya penurunan produktifitas upaya tangkap. Tujuan
yang ingin dicapai dari penelitian ini adalah untuk mendapatan gambaran pola penyebaran
udang putih yang tertangkap oleh setnet dan mendapatan gambaran kecenderungan CPUE
dari perikanan udang putih kecil. Sebelas stasiun didirikan di estuari untuk mengetahui pola
penyebaran udang putih kecil yang tertangkap oleh setnet. Data produksi tahunan udang
putih kecil dan jumlah hari tangkap (trip) digunakan untuk mengetahui kecenderungan
CPUE. Hasil dari kajian ini menginformasikan bahwa udang putih kecil lebih banyak
tertangkap pada salinitas 5 – 7 ‰. Udang putih kecil yang berukuran lebih besar pada
umumnya tertangkap pada perairan yang lebih dalam dan salinitas yang lebih tinggi. CPUE
dari perikanan udang putih keci cenderung mengalami penurunan sepanjang tahun. Hasil
kajian ini diharapan dapat memberikan informasi bagi perencanaan pengelolaan untuk
mengelola perikanan udang putih kecil secara berkelanjutan.
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© Copyright property is owned by Bogor Agricultural University (IPB), 2006
All rights reserved
This thesis or parts thereof may not be reproduced in any form without written consent
from Bogor Agricultural University (IPB)
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STUDY ON CAPTURE OF SMALL WHITE SHRIMP (
Metapenaeus
lysianassa,
de Man 1888
)
AS A MANAGEMENT APPLICATION IN
SUNGAI KAKAP ESTUARY KABUPATEN PONTIANAK
WEST KALIMANTAN
SAPTOYO
Thesis as Partial Fulfillment for Master Science
In Marine and Coastal Resources Management
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
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Thesis title
: Study on Capture of Small White Shrimp (
Metapenaeus lysianassa
, de
Man 1888
)
as A Management Application in Sungai Kakap Estuary
Kabupaten Pontianak West Kalimantan
Name :
Saptoyo
Register Number
: C251040374
Approved by advisory board
Dr. Ir. Yusli Wardiatno, M.Sc.
Supervisor
Dr. Unggul Aktani
Dr. Ir. Sulistiono, M.Sc.
Co-supervisor Co-supervisor
Acknowledged by
Head of Study Program
Dean of Post Graduate School
Prof. Dr. Ir. Rokhmin Dahuri, MS.
Dr. Ir. Khairil Anwar Notodiputro, MS.
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PREFACE
Thesis with title “Study on Capture of Small White Shrimp (
Metapenaeus
lysianassa,
de Man 1888) as A Management Application in Sungai Kakap estuary
Kabupaten Pontianak West Kalimantan” was composed to fulfill the requirement to achieve
Master Science on Study Program of Marine and Coastal Resource Management, Post
Graduate School, Bogor Agricultural University. The choice of this title is related to author
enthusiasm to learn small white shrimp fishery in Sungai Kakap estuary which has been
conducted by artisanal fishermen since more than twelve years ago.
Hereby I would like to deeply thank to all of the persons who support, help and
motivate so that I could finish this study program and thesis composing on time, as follow:
1.
Dr. Ir. Yusli Wardiatno, M.Sc, Dr. Ir. Unggul Aktani, M.Sc and Dr. Ir. Sulistiono, M.Sc
as my supervisors who gave tuition, assistances and instruction from proposal
composing to thesis finishing.
2.
Dr. Ir. Ridwan Affandi, DEA as a guess examiner and Ir. Santoso Raharjo, M.Sc as a
academic commission examiner who gave correction and suggestion for thesis
improvement
3.
My colleagues in post graduate sandwich program; Zainal, Zaitul, Afrizal, Machmud,
Kusdiantoro, Coki, Edo, Normawati, Netti, Eiren and Yesi. I would like to say thank
you very much for your kindness, friendship, togetherness, cooperation, support and
advices
4.
The official of post graduate sandwich program; Dr. Ir. Bambang Widigdo, M.Sc,
Dr. Ir. Yusli Wardiatno, M.Sc, Dr. Ir. M. Muklis Kamal. M.Sc and Mrs. Ola who
assisted and facilitated the need of sandwich students during study time
5.
Prof. Vibeke Simonsen and Prof. Lars Lund Hansen from Arhuss University Denmark
that gave many suggestion and guidance in composing process of minor thesis when
the study conducted in Arhuss University Denmark
6.
Mr. Hardiyono and staff in PPI Sungai Kakap who facilitated and gave assistances
during the study time
7.
All of the relations who could not be mentioned individually. Thank you for your
assistances and cooperation.
Finally with my sincerely this thesis might give information for everyone who need
to learn related to the thesis topic.
Bogor, September 2006
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BIOGRAPHY OF AUTHOR
The author is the fourth from five brothers, Author was
born in Desa Kuntili, Kecamatan Sumpiuh Kabupaten Banyumas
on 09 October 1969 from the couple of Darmuji and Restinem.
Childhood period was experienced in peacefull countryside Desa
Kuntili with his brothers and his beloved parents. Playing football,
cycling, swimming in the river are very unforgettable beautiful
memory.
In 1983, the author was graduated from elementary shcool (SDN III Kuntili
Sumpiuh), in 1985 the author was graduated from Yunior High School (SMPN II
Sumpiuh), in 1988 the author was graduated from Senior High School (SMAN Sumpiuh) ,
in 1993 the author was graduated from diploma III High Shool of fishery ( STP Jakarta)
majoring in machinary technology, in 1993 the author worked as a masinist of tuna fishing
vesel that has landing base in Jakarta fishing port. From 1994 to present, the author work as
a government employee at Marine and Fishery Agency of West Kalimantan Province.
In 1996 the author has merried Desi Kartika and they has two nice sons. The first
son name is Rachmadanu Fitra Panutan who is sitting in the fourth class of elementary
school and the second son name is Shafli Bayu Prakarsa who is still sitting in pra
elementary school. In 1999 the author was graduated from S.1 economic faculty of
Tanjungpura University Pontianak. In 2004 the author got schoolarship for post graduate
program in marine and coastal resource management of Bogor Agricultural University
cooperated with Aarhuss University of Denmark from Marine and Coastal Resources
Management Project (MCRMP) which was organished by Marine and Fishery Affair
Departement of Republic Indonesia.
Bogor, September 2006
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DEDICATION
TO
My mother, Restinem and my father, Darmuji who have mothered, educated, guided and
prayed so that I have better position and better education
And
TO
My sons, Rachmadanu Fitra Panutan and Safli Bayu Prakarsa who always give inspiration
and reflect my future and my beloved wife, Desi Kartika who has acompanied patiently and
given moral support during the study time
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CONTENT
Page
List of tables.. ...
vi
List of figures ...
vii
List of apenddixs. ...
viii
INTRODUCTION
Background ...
1
The objective...
2
Research Framework……….
2
LITERATURE REVIEW
Shrimp resource……….
4
Taxonomy and life cycle of shrimp………...
4
Morphology of penaeid shrimp ………...
6
General behavior and shrimp habitat ………….………...
7
Estuary Biota……….
8
Capture fisheries management………..
9
The objective of fisheries management ………...
10
Fishery regulation ………. ……….
12
MATERIALS AND METHODS
Study site ………..………..
14
Respondent ………..
14
Setnet………. ………..………
15
Shrimp length ………. ……….
16
Shrimp weight………..………...
16
Environment parameter………....………
16
Data analysis ………. …….
17
Formulation of catch per unit effort (CPUE)………
18
Economic analysis of small white shrimp fishery in Sungai Kakap estuary ………
18
THE CONDITION OF STUDY SITE
Geographic position ……….
19
Soil condition ………
19
Demography of Kecamatan Sungai Kakap ….………
19
Fishermen in Sungai Kakap estuary ………
20
The ecological condition of Sungai Kakap estuary ……….
20
Fisherman organization ..……….
22
Supporting facilities for fisherman………. ………. ………
22
RESULTS
The numbers of small white shrimp (
Methapenaeus lyssianassa
) caught by setnet
24
Sizes distribution of small white shrimp caught by setnet ………..
26
Distribution of setnet ………
27
Catch per unit effort (CPUE) of small white shrimp caught by setnet …….… …..
28
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DISCUSSION
The numbers of small white shrimp (
Methapenaeus lyssianassa
) caught by setnet
32
Sizes distribution of small white shrimp caught by setnet ………..
34
Distribution of setnet……… ………
38
Catch per unit effort (CPUE) of small white shrimp fishery……….. ….
38
Economic analysis of small white shrimp (
Metapenaeus lysianassa
) fishery …….
37
Management implications ………
38
CONCLUSSION AND SUGGESTION
Conclusion ………
40
Suggestion ………
40
REFFERENCE ………..
41
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LIST OF TABLES
Page
1. The population of Kecamatan Sungai Kakap , 2003 ………..………....
20
2. Fishermen numbers and fishing gears in Sungai Kakap estuary ……… 20
3. The species of shrimp and fish caught by fishermen from estuary of Sungai Kakap …. 22
4. Fishermen organization of Kecamatan Sungai Kakap ………
22
5. Supporting facilities for fisherman……….. 23
6. Sediment type in Sungai Kakap estuary ……….
27
7. Annual trend ofsmall white shrimp catch and CPUE during 1994 – 2005 ………
29
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LIST OF FIGURES
Page
1. Research framework ………..
3
2. Physical picture of small white shrimp ……….
5
3. External genital organ of small white shrimp (Lovett, 1981) ………
5
4. Life cycle of penaeid shrimps ( Keyon, 2004)………
6
5. General shrimp morphology (Whitaker, 2004) ………..
6
6. Research stations deployment in Sungai Kakap estuary ……… 14
7. Setnet sketch of small white shrimp in estuary of Sungai Kakap ………..
15
8. Standard length measurement for shrimp (From English, S. et al, 1994) ……….
16
9. Shrimp weight measurement using digital weight balance………. ……..
16
10. Intake method of bottom water using bottle fastened on the stick conducted during
the research ………
17
11. Salinity measurement method using refractometer (From English, S. et al, 1994 …….
17
12. Profile of Sungai Kakap Estuary………. 21
13. The number of small white shrimp caught at research stations ……….
24
14. The relationship between shrimp catch and water salinity ….……….
25
15. Water salinity distribution in Sungai Kakap estuary Kabupaten Pontianak West
Kalimantan ………
25
16. Carapace length frequency distribution of small white shrimp caught by setnet, April
– June 2006 ………
26
17. The average total length of small white shrimp caught by setnet in Sungai Kakap
estuary compared to water depth and salinity. ………..
27
18. Setnet distribution in Sungai Kakap estuary Kabupaten Pontianak West Kalimantan .. 28
The CPUE trend during twelve years from the year 1994 – 2005 ………...
29
19. The correlation between effort and CPUE of small white shrimp in Sungai Kakap
estuary ………
30
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LIST OF APPENDIX
Page
1
Map of research site in Kecamatan Sungai Kakap Kabupaten Pontianak West
Kalimantan ………...
47
2
Small white shrimp catches from research stations in Sungai Kakap estuary……
48
3
Small white shrimp catches and environment parameters ………...
49
4
Carapace length frequency distribution of small white shrimp ………..
51
5
Anova analysis for carapace length frequency distribution of small white shrimp
(April, May, June 2006) ………...
51
6
Length distribution of small white shrimp caught by setnet from research stations
………
52
7
The average of total length compared ambient parameters ………
63
8
Correlation analysis between the average of shrimp total length and salinity ……
63
9
Correlation analysis between the average of shrimp total length and transparency
……….
64
10 Correlation
analysis
between the average of shrimp total length and depth ……..
64
11 Annual trend of small white shrimp catch and CPUE caught by setnet in Sungai
Kakap estuary ………..
65
12 Correlation analysis between effort and CPUE of small white shrimp …………..
65
13 Setnet numbers in estuary of Sungai Kakap ………..
66
14 Ambient parameters during the research ………
67
15 The setnet owner in Sungai Kakap estuary in the year 2006 ………...
70
16 Fixed cost of small white shrimp fishery using setnet in Sungai Kakap estuary
Kabupaten Pontianak ……….
73
17 Operational cost of small white shrimp fishery using setnet in Sungai Kakap
estuary ………
75
18 Small white shrimp production April – June 2006 ………
76
19 Average of fisherman income from small white shrimp fishery using setnet from
April – June 2006 ………
76
20 The computation season type of small white shrimp in Sungai Kakap estuary…..
77
21 Small white shrimp catching index in Sungai Kakap estuary 1994 – 2005………
81
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INTRODUCTION
Background
Kecamatan Sungai Kakap has a coast line facing directly to South Chinese Sea. Most of this area is covered by mangrove plants such as; Bruguiera, Sonneratia, and Nypha frutican. Therefore this area has high potency of marine biodiversity (Marine and Fisheries Agency of West Kalimantan Province 2002).
The potency of fishery resources in this region consist of; fish, shrimp, crab and mollusks. However, shrimp resource is more dominant exploited by fisherman at the moment. The potency of shrimp resources in this region consists of; small white shrimp (Metapenaeus lysianassa), yellow shrimp (Metapenaeus brevicornis), greasbaek shrimp (Metapenaeus ensis), red shrimp (Solenocera subnuda) and white shrimp (Penaeus indicus). Most of the shrimp resources are caught by trawlers except small white shrimp (Metapenaeus lysianassa) that is caught by setnet because this shrimp occur in shallower marine water.
Most of the people living in coastal area of Kecamatan Sungai Kakap are fisherman. They generally work as a fishing boat crew or work using their own fishing boats to fulfill their family need. Their catches are landed in Sungai Kakap Catch Landing Base that is facilitated by some infrastructures such as leaning pond, bridge, auction hall, warehouse, fuel station, docking, and other facilities. According to Marine and Fisheries Agency of Kabupaten Pontianak (2003) the number of fisherman in Sungai Kakap Landing Base tends to increase every year. The recent record in 2003 showed that the number of fisherman is 930.
Most of the fisherman in this region catches fish or shrimp in marine water of South Chine Sea not far from their village using gillnet, trap, long line, hook and trawl. This activity gives high income for fisherman but the operation cost is relatively high. Therefore, not all of fishermen have capability to catch fish or shrimp in offshore waters. Fishery resource in estuary water is the only choice for artisanal fisherman in Kecamatan Sungai Kakap. At present, there are several of fishing gears used by fisherman to exploit fishery resources in Sungai Kakap estuary such as setnet, trap, casnet, hook and other gears. One of fishery commodities which has high price in the market is small white shrimp (Metapeanaeus lysianassa). Therefore most of fishermen in this region are more attracted to catch it. Setnet is the most used gears to catch it. The use of setnet tends to increase during the decade. For example in 1994 the setnet number was just 50 units but in 2005 setnet numbers increased up
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2 to 123 units. (Fishery and Marine Agency of Kecamatan Sungai Kakap 2005). The increasing numbers of setnets in this estuary provides more work for fishermen. It also increases total catch of shrimp production landed in catch landing base of Sungai Kakap. However, the condition does not automatically have positive relation toward fishermen productivity. CPUE trend of small white shrimp fishery in Sungai Kakap estuary is estimated to decrease during the decade. According to Naamin (1992) in order to achieve success in managing penaeid shrimp resources, the knowledge of biological aspects, such as name and recognition, life cycle, habitat, ambient parameter, distribution and spawning season, are very important.
Interconnected to the issues, there are some questions to be addressed to the shrimp fishery utilization as follow:
1) What is distribution pattern of small white shrimp caught by setnet in Sungai Kakap estuary?
2) How is size distribution of the small white shrimp caught by setnet in Sungai Kakap estuary?
3) What is the spatial distribution pattern of setnet operated by fisherman in Sungai Kakap estuary?
4) What is CPUE trend of the small white shrimp resource caught by setnet in Sungai Kakap estuary?
The objectives
Based on many issues of small white shrimp fishery and to answer several questions above, the objectives of the study are:
1) To obtain the distribution pattern of small white shrimp caught by setnet in Sungai Kakap estuary
2) To obtain the sizes distribution of small white shrimp caught by setnet in Sungai Kakap estuary
3) To reveal the spatial distribution of setnet deployment in Sungai Kakap estuary 4) To obtain CPUE trend of small white shrimp caught by setnet in Sungai Kakap
estuary
Research framework
Shrimp are important food for the country which gives a contribution to provide protein, work and also national income. The old regime polices in fisheries production is solely for production orientation, which may lead to over exploitation of shrimp resources. However, new paradigm in coastal resources utilization has
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3 been changed into sustainable development. Therefore in managing coastal resources, some factors such as the potency of the resources, numbers of fishing gears, fishing efforts, biological information of the resources, etc are needed. Research framework of this study can be seen in Fig. 1.
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LITERATURE REVIEW
Shrimp resourcesShrimp resources are essential food source that contains protein to support human life. This resource has been utilized by human since long times ago to fulfill their need. Shrimp resource is a renewable resource. However, this resource does not mean no limitation to exploit. Therefore it needs good management to ensure the sustainability of shrimp resource and to give contribution toward; protein, economic and community prosperity (FAO 1996).
Taxonomy and life cycle of small white shrimp
Small white shrimp taxonomically is classified as follows (Lovett 1981): Phylum: Arthropoda
Class: Crustacea
Sub class: Malacostraca Series: Eumalacostraca
Super order: Eucarida Order: Decapoda
Sub order: Natantia Family: Penaeidae
Genus: Metapenaeus
Species: Metapenaeus lyssianassa (de Man 1888) Common name: Small white shrimp
Local name: udang ambai (West Kalimantan)
Physically small white shrimp has reddish yellow color with brown spot on the body. The color of walking and swimming legs are yellowish white with blue spot encircles on the leg ankles. The color of shrimp tail includes telson and uropod is reddish yellow with nutbrown spot on the tail tip. The physical picture of small white shrimp is expressed in Fig. 2.
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5
Fig. 2. Physical picture of small white shrimp (Metapenaeus lysianassa) This shrimp has a short rostrum with six teeth on top of rostrum and there are not teeth on underside of rostrum. Physically sex can be differentiated based on genital organ of shrimp. Male of small white shrimp is characterized with petasma that is located between the first of swimming legs (pleopod) and female of small white shrimp is characterized by thelycum that is located between the fourth and fifth of walking legs (periopod). External genital organ of small white shrimp is expressed in Fig. 3.
Fig. 3. External genital organ of small white shrimp (Lovett 1981)
Shrimps occur and inhabit both marine and estuary habitats and adult shrimps spawn offshore in marine waters. The fertilized eggs become free swimming larvae and after several moults they enter estuary and coastal wetlands (Turner 1983). Wetlands within the estuary offer both a concentrated food source and a refuge from predators. After growing into juvenile the shrimps leave the estuary to move offshore where they become adults. The migration of shrimps from shallow estuary to deeper
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6 marine water are influenced by tides, lunar cycles, maturation state, and estuary temperature change (Blackmon 1974). Life cycle of penaeid shrimp in general can be seen in Fig.4.
Fig. 4: Life cycle of penaeid shrimps ( Keyon 2004)
Morphology of penaeid shrimp
Shrimp is a large group of crustaceans that include varying in size from 2 cm to over 35 cm in length. In general, shrimp body of genus penaeidae is almost laterally compressed, the rostrum is usually composed and toothed and the abdomen longer than the carapace (Chaitiamvong and Supongpan 1992). Futhermore they also mention that morphological features of penaeidae shrimp includes the rostrum and the carapace, antennules and antennae, maxillipeds, pereopods and branches, pleopods. According to Lovett (1981), penaeid shrimp has characteristics that include gill numerous. Rostrum laterally compressed, usually well developed and rostrum has more than 3 teeth. General shrimp morphology is presented in Fig. 5
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7 Shrimps have two pairs of whiplike antennae that contain sensory organs for taste and touch, which help shrimps to find food. Bottom-dwelling species are quickly attracted by the scent of dead remains. Many shrimp’s species also have bulging compound eyes that are made up of hundreds of lenses joined together. The eyes act as an early warning system against predators. Shrimps react instantly if they see anything moving overhead. Deep-sea shrimps have light-producing organs, called photophores, that scientists believe may help to identify mates in the dark depths of the sea (NOAA 2001).
General behavior and shrimp habitat
Shrimp is considered as a nocturnal biota. Shrimp prefer to forage at the night than at the day time. They also like to hide inside the mud or stick on the objects that sink in the water. Cannibalism behavior is common phenomenon in shrimp (Suyanto and Mujiman 2004).
Naturally the food of shrimp depends on their life stage. During larva stage, shrimp feeds plankton. In nature, adult shrimp feeds soft meat fauna, crustacea, worm, etc.(Suyanto and Mujiman 2004). Furthermore Thomas (1978) explains that considerable differences have been noticed in the food preferences of the various larva stages, juvenile and adult shrimp. The larvae in the nauplies stage do not feed at all, as they have food reserve in form of yolk. But protozoea larvae feed voraciously on phytoplankton. Adult shrimps feed on a variety of animal and plant material available in the area where they live.
Marine shrimps live in wide distributed marine waters in all over the world. Their habitat includes shallow marine water, estuary with low salininty. Some of them even inhabit nearly fresh water boundary and in contrast, some other species prever to live in open deep sea with high salinity. They ussually prever to stay in muddy substrat and others prever to stay in coral reefs (Dore and Frimodt 1987). Futhermore Macia (2004) explain that the habitats preferred by penaeid species are diverse, include mangroves, seagrass and macroalgae as well as estuaries, mudflats and sand flats.
One of good habitats for shrimp is mangrove ecosystem. According to Primavera (1997) mangrove ecosystem has a capability to provide food availability, as nurseries for shrimp and it also shelters shrimp from predator. Predation is probably the major cause of shrimp mortality because food supplies in estuarine habitats and mangrove are adequate and penaeid juveniles have a wide range of
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8 tolerance to physicochemical factors. Protection from predation is offered by physical structure (e.g. seagrass blades and mangrove roots), substratum and turbidity, in combination with shrimp behavior such as hiding and burying. Futhermore Hossain (2001) explains that mangrove ecosystem is a suitable feeding, breeding and nurshery ground for various marine, estuarine and freshwater fishery resources. The net like spread root system of mangrove plays as a coastal stabilizer and binder of sediment and thus aids in preventing erosion in mangrove areas.
Lovett (1987) and Dore (1997) mention that habitat of shrimp Genus
Metapenaeus is rather difference with others. Metapenaeus shrimp ussually inhabits and be distributed throughout the shallow coastal water and sometime found in brackish water, creeks, swam and even in nearly fresh water. Most of the shrimp are classified as small shrimps and their distribution in the Indo West pacific region range from Pakistan, Malaysia, Indonesia and Thailand (Dore 1997). Beside that genus Parapeneopsis is also widely distributed in shallow coastal waters. On the other hand the members of genus Penaeus, Solenocera, Metapenaeopsis,
Trachypenaeus are all deep water shrimp species that do not commonly occur in abundance in coastal waters (Lovett 1987).
According to Aziz et al. (1983) the distribution of penaeid shrimp in Indonesia achieve 26 species. Penaeidae has 110 species that is separated in some places in the world. Furthermore that penaeid shrimps that inhabit in the marine water of Indonesia consist of Penaeus merguiensis, Penaeus indicus, Penaeus orientalis, Penaeus monodon, Penaeus semisulcatus, Penaeus canaliculatus,
Penaeus latisulcatus, Metapenaeus ensis, Metapenaeus affinis, Metapenaeus dobsoni, Metapenaeus elegans, Metapenaeus endeavouri, Metapenaeus monoceros,
Metapenaeus lyssianassa, and some species of Trachypenaus, Parapenaeopsis and
Solenocera.
Estuary biota
There are some definitions of an estuary because several geomorphologic features of coastlines. According to Nybakken (1997), an estuary is a place where freshwater and saltwater meet and mix. This definition implies the free connection of the sea with the freshwater source, at least during a part of the year. Furthermore Nybakken (1997) mention that most estuaries have soft, muddy substrates. These are derived from sediments carried into estuary by both seawater and freshwater.
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9 Estuary is highly dynamic coastal environment which are influenced by physical, chemical and biological aspects, seasonal and tidal changes in temperature, salinity and other factors (Kennish 1990). According to Blaber (1997), the tropical estuary environment can be divided into four categories. The first is open estuary, the second is estuarine coastal water, the third is blind estuary and the last is coastal lake. Open estuary are never isolated from the sea and subject to tidal influence with all its physical consequences of regular salinity, turbidity and current flow changes, tidal prism, haloclines and intertidal habitats.
According to Kennish (1990), the structure estuary water can be classified into four groups during low flow condition base on average annual salinity of estuary water, as follow: the first is polyhaline estuary that has water salinity from 18‰ to 30‰, the second is mesohaline estuary that has annual water salinity from 5‰ to 18‰, the third is ougohaline estuary that has annual water salinity from 0.5‰ to 5‰ and the last tidal fresh water estuary that has annual water salinity less than 0.5‰
There are three types of fauna in estuaries; marine, freshwater and brackish water or estuarine fauna. Marine fauna that inhabit in estuaries have characteristic to be unable or barely able to tolerate salinity changes. These organisms are usually restricted to the mouths of estuaries where salinity is generally 25‰ or above. These faunas are often the same species found in the open sea. The brackish water or true estuarine species are found in the middle reaches of the estuary in salinities between 5-18‰ but not found in freshwater or in full seawater. The last fauna found in estuary is derived from freshwater. These types of fauna usually cannot tolerate salinities much above 5‰ (Nybakken 1997).
Furthermore Osborne (2000) explains that estuaries are not easy places to inhabit and few species have been able to adapt to estuarine conditions because organisms that live in estuaries to be able to cope with salinity changes. Species that have adapted often thrive there, developing into adult and they become productive populations. The composition of fauna variety and diversity in estuary depends upon in the size, depth, physical characteristics such as salinity and turbidity and also geographical location of estuary in relation to marine feature such as ocean currents, canyons and reefs (Blaber 1997).
Capture fisheries management
Fisheries management can be defined as the use of all types of information (ecological, economic, political and socio-cultural) in decision making to achieve
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10 goals related to the use of fisheries resources (Karjalainen and Marjomaki 2005). The goals of capture fisheries management are complex and broad in concept, touching benefits such as increased food supply, increased earnings of poor people or increased export earnings are inherently good goal but the realization of these goal are complex because of the diversity of the fisheries (Royce 1996).
According to Karjalainen and Marjomaki (2005) fisheries management consists of some elements as follow:
1) Assessment (i.e. determining stock sizes, the extent of fishing efforts and fishing catches and recognizing alternative management objectives)
2) Decision making
3) Selection of harvest strategy and tactics
4) Implementation of chosen set of management tactics and measures, and 5) Controls over implementation
Furthermore ISRS (2004) explains that in order to achieve goals related to the use of fisheries resources, fisheries management has six basic options. These include restricting to:
1) The numbers of people or boats fishing 2) The time allowed for fishing
3) The fishing area 4) Gear or technology
5) The sizes that can be harvested 6) The species being selected
According to Karjalainen and Marjomaki (2005) in capture fisheries management, the extent of fishing efforts will be adjusted to produce a sustainable state, i.e. the maximum biomass, maximum fishing employment, maximum sustainable yield, and maximum economic yield.
The objectives of fisheries management
The objectives of fisheries management according to Wallace and Fletche (1996) are to ensure the sustainable production over time from fish stocks, preferably through regulatory and enhancement options that generate economic and social well being of the fishermen and industries that use the production. According to Reynold (2002), the goal of fisheries management is to maximize the economic opportunities and benefits from the State’s waters within sustainable harvesting limits. Within this
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11 context, according to Bonfile (2004), fisheries management objectives can be defined into at least three categories as follow:
1. Biological and Conservation Objectives
In modern world of fisheries, management tries to balance multiple objectives that span beyond biological concerns. Standard indicator of biological yield is the annual weight or number fish / shrimp caught.
2. Social objectives
Social objectives are concerned with employment and equity. Fisheries are not only about landing fish and making money out of it, but also about employing people and making sure that those involved in the fisheries make a living that is adequate and sustainable.
3. Recreational objectives
For recreational purposes, both the catch and effort (number of successful fishing trips) might be important objectives. The total number of fish available, and in specific case of trophy fish (such as marlins, swordfish or tunas), the size of the fish will be outmost important. It may be possible that the standard indicators for recreational fisheries include the estimated total value of recreational effort and the number and size of the recreational catch.
According to Silvester and Pauly (1997), fisheries management may be viewed as a dynamic resource allocation process where the ecological and institutional resources of a fishery exploitation system are distributed with value to society as the overall goal. The fisheries management process shall include the resolution of normative and empirical debate to determine the direction of resource decisions where the final goal of fisheries management is to achieve a sustainable fisheries development. The sustainable fisheries development can be defined into some purposes as follow:
1. Productivity / efficiency, for examples; high fish production / revenue, high catch / effort, high foreign exchange earnings, supply stability and high returns on investment
2. Distribution equity, for examples; equal access to production factory, reasonable artisanal catches, reasonable fish prices, reasonable artisanal income, and high employment level.
3. Environment integrity, for examples; reasonable water quality, reduced pressure on critical habitats, reduced stress on biodiversity and use of nondestructive gears.
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12 4. Institutional efficiency/effectiveness. The effectiveness of governmental
institutions in managing fisheries sector is very important to minimize budget loss and optimize the objectives that will be derived in managing fisheries sector.
Furthermore according to NSW Fisheries (2003), the goals of shrimp management interconnected with many issues on shrimp fisheries are:
1) To manage the shrimp trawl fishery in a manner that promotes the conservation of biological diversity in the marine water environment.
2) To maintain target and bycatch species harvested by the shrimp trawl fishery at sustainable levels.
3) To promote the conservation of threatened species, populations and ecological communities associated with the operation of the shrimp trawl fishery.
4) To appropriately share the resource and carry out fishing in a sustainable manner that minimizes social impacts.
5) To promote a viable commercial fishery (consistent with ecological sustainability).
6) To ensure cost-effective and efficient management and compliance in the marine water shrimp fishery.
7) To improve the knowledge of the community about the operations and management of the shrimp trawl fishery.
8) To improve the knowledge about the shrimp trawl fishery and the resources upon which the fishery relies.
Fisheries regulation
Reviewing to the symptom of overfishing that occurred in some marine water areas, government regulation which arranges the exploitation level of fisheries resources become very important. The aim of fisheries regulation should also accommodate all of important needs not only for human life but also for environment itself. According to King (1997) fisheries regulation are imposed on fishery to support a strategy designed to achieve predefined objective. Furthermore King also mentions that fisheries regulation also important to protect particular parts of stock. Small individuals can be protected by regulations such as minimum mesh size, legal minimum length and closures, and breeding stock can be protect by closed seasons. Government intervention to reduce the negative impact of fisheries activities can be undertaken through input control and output control. Input controls can be done trough; limiting the number of fishing units, limiting the efficiency and type of
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13 fishing gear, closures, minimizing the mesh sizes and escape gaps in the traps. Output controls can be done trough; sizes limits (minimum legal lengths), rejection of females or spawning females, catch quotas, and enforcement of regulations.
Regionally, regulation of fishery resources established by local government of Kabupaten Pontianak at present are still limited. Most of fishery policies are orientated on tax and retribution from fishery commodity. For examples local government regulation established by Kabupaten Pontianak number 12 in the year 2002 is about retribution at fishery business (Perda Kabupaten Pontianak 2002). The latest regulation established by local government in the year 2006 is about fish auction retribution. (Draft Perda Kabupaten Pontianak 2006). Fishery regulation which regulates fishing gear deployment, preservation and protection of marine and fishery resources in this region are still not available.
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MATERIALS AND METHODS
Study siteThis study was conducted in April 2006 – June 2006, in Kecamatan Sungai Kakap, Kabupaten Pontianak, West Kalimantan. To study shrimp distribution in Sungai Kakap estuary, twelve stations were established in this site. The station was based on the salinity. The station position was measured by hand held GPS (global position system). The station deployment is expressed in Fig.6.
Fig.6. Stations deployment in Sungai Kakap estuary
The shrimp samples were taken from stations one time a week at ebb tide period with time interval 05.30 – 9.00 a.m. during 15 minutes operation and shrimp samples were counted and identified.
Respondents
In this study the information on the price of small white shrimp and operational cost to catch the shrimp is needed for economic analysis. The information was obtained by interviewing fishermen. The number of interviewed fisherman (as respondents) was determined by Tuwu (1993).
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15
n = N / (1 + Ne2 ) Where:
n = Sample size N = Population size e = Critic value (10%)
The numbers of small white shrimp fisherman calculated by the formula were 48 people (Appendix 2).
Setnet
Setnet is the main gear to catch small white shrimp in Sungai Kakap estuary (local name: jaring ambai). Setnet materials consist of; the end pocket with 0.5 inch mesh size from pholyetiline, the middle pocket with 1 inch mesh size from pholyetiline, the front pocket with 1.5 inch mesh size from pholyetiline. To direct the shrimp comes to the pocket, fisherman constructs wing in each side. Setnet wing is built from bamboo or frond of Nypha frutican. The sketch of setnet is illustrated in
Fig.7.
Fig.7. Setnet sketch of small white shrimp in estuary of Sungai Kakap
Shrimp length
Shrimp length measurement was divided into total length and carapace length. This measurement was undertaken to obtain the information of shrimp length composition from stations. The length measurement is illustrated in Fig.8.
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16
Shrimp weight
The weight of shrimp was measured by electronic digital balance (brand camry, model EHA121, with capacity 200 gram/128.7dwt/6.432ozt). The picture of this tool is showed in Fig.9.
Fig.9. Shrimp weight measurement using electronic digital balance conducted in the field
Environmental parameters
Environment parameters measured directly in this study were water salinity, water brightness, water dept, water surface temperature and air temperature. The measurements of environment parameters were undertaken after harvesting of the shrimp at every station during ebb tide. Water salinity of the stations were measured using refractometer, brand Atago S/Mill and water surface temperature was measured using mercury thermometer. Water depth was measured by stick that was sunk into the bottom of estuary water at every research station. The illustration of water measurement process conducted in the field can be seen in Fig. 10 and Fig. 11.
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17
Fig.10. Intake method of bottom water using bottle fastened on the stick conducted during the research
Fig.11. Salinity measurement method using refractometer (From English, S. et al 1994)
Measurement of sediment texture was taken from four stations, two points were undertaken at stations in the river water and the others were undertaken at stations in the inner of estuary water. The sample weight of each station was 600 gram. The total samples were transported to laboratory to identify the composition of sediment texture.
Data analysis
ANOVA two - way without replication is used to analyze carapace length frequency of small white shrimp caught by setnet during three month observations. According to Sokal in Nasrullah (1991) this analysis can be used to analyze the variance of two or more variables. Non parametric test is used to analyze the correlation between sizes distribution of shrimp and water salinity and to analyze the correlation between CPUE and effort undertaken by fishermen to catch small white shrimp resource in this estuary. According to Henderson (2004) non parametric test do not assume that the samples were drawn from a normal population. Almost no data on abundance or distribution of plants or animals will conform to a normal
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18
distribution, so non parametric test correlation analysis can be used to analyzes are more appropriate for ecological studies.
Formulation of catch per unit effort (CPUE)
The sustainable estimation of shrimp fishery in Sungai Kakap Estuary can be predicted from the capture productivities or it is well known as a CPUE (catch per unit effort) done by fishermen in certain time. According to King (1985) that the basic principle of using CPUE data is that changes in CPUE accurately reflect changes in the abundance of fish in the stock. Furthermore Lynch (2004) explains that catch per unit effort is an important component of stock assessment as catch alone is often a misleading indicator of stock abundance. CPUE can be formulated as follow:
………. (1) Where:
h = harvest (kg) E = effort (trip)
Economic analysis of small white shrimp fishery in Sungai Kakap estuary
Total cost needed by fisherman to catch small white shrimp consists of fixed cost and variable cost. Fixed cost is required investment to establish effort unit. Variable cost is needed to pay the operational requirement for sailing. Total cost is formulated as follow:
TC = fix cost + variable cost ………..(2)
Total revenue is gross income derived from selling of shrimp production. Total revenue is formulated as follow:
TR = p. h ………(3)
Where:
P = shrimp price
h = harvest (production)
Benefit is net income derived from selling of shrimp production. Benefit is formulated as follow (Seijo et al 1998):
π
= TR – TC ………..(4) Where:Π = benefit; TR = total revenue; TC = total cost E
h
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THE CONDITION OF STUDY SITE
Geographic positionKecamatan Sungai Kakap geographically is located at 0,1˚ 55”S – 0,15˚33” S and 109˚ 4” E - 109˚ 21” E or located in equator line with average of rain fall 4250 mm/year and air temperature between 21° C to 35° C . Kecamatan Sungai Kakap consists of 12 villages with capital city Sungai Kakap (Appendix 1). The area of Kecamatan Sungai Kakap is 48.397 Ha with area boundary:
West site : South Chine Sea
South site : Kecamatan Teluk Pakedai East site : Kecamatan Pontianak Barat
North site : Kecamatan Pontianak Utara and Kecamatan Siantan
Soil condition
In general, soil condition of Kecamatan Sungai Kakap can be classified into two groups:
Alluvial soil : Young soil from sedimentation of mineral material carried by river water. The characteristics of this soil is grey to brown color, sandy and clay texture, hard in dry condition, low content of organic material. The soil pH of is depend on the soil structure (Erwanto and Kartono 2005).
Organosol soil : It is also known as peat soil. This soil structure consists of more than 65% organic material. This soil has brown to black color. pH of this soil is varied between 3 – 5, carbon content 58%, H 5%, O 34% and N 2%. Organosol soil is easy found in coastal area of West Kalimantan (Erwanto and Kartono 2005).
Demography of Kecamatan Sungai Kakap
The population numbers of Kecamatan Sungai Kakap are 88.678 people with 44.952 men and 43.726 women. The population of each village is described in Table
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Table 1: The population ofKecamatan Sungai Kakap 2003
No Village Male Female Total
1 Sepuk Laut 1,294 1,194 2,488
2 Punggur Besar 4,683 4,482 9,165
3 Punggur Kecil 5,134 5,117 10,251
4 Kalimas 2,811 2,737 5,548
5 Tanjung Saleh 2,490 2,619 5,109
6 Sungai Belidak 1,107 1,144 2,251
7 Sungai Kakap 5,287 5,079 10,366
8 Sungai Itik 2,091 1,999 4,090
9 Pal IX 7,537 7,374 14,911
10 Sungai Rengas 8,304 7,851 16,155
11 Jeruju 2,720 2,679 5,399
12 Sungai Kupah 1,494 1,451 2,945
TOTAL 44,952 43,726 88,678
From: Statistical data of Kecamatan Sungai Kakap, 2003
Fisherman in Sungai Kakap estuary
Most of fishermen in Sungai Kakap estuary come from the villages; Sungai Kakap, Sungai Itik, Tanjung Saleh, Punggur Kecil and Punggur Besar. According to Fisheries and Marine Agency of Kecamatan Sungai Kakap (2006) the numbers of fishermen are 356 people. Most of them are artisanal fisherman. They sell and also consume a part of the shrimp catches. The numbers of fisherman can be seen in the
Table 2.
Table 2: Fisherman numbers and fishing gears in Sungai Kakap estuary
Number of
gears Fishermen
No Name Target Catch
(Unit) (Person)
1 2 3 4 5
1 Set Net (filter net) small white shrimp 123 246
2 Rompong (trap)
macrobrachium rosenbergii,
fish,mud crab 200 30
3 Belat (trap)
mud crab, macrobrachium
rosenbergii, fish 23 23
4 Gill Net fish 24 24
5 Rawai (Long Line) fish 23 23
6 Jala (Cas net) fish 10 10
Amount 407 356
From: Fisheries and Marine Agency of Kecamatan Sungai Kakap, 2006
The ecological condition of Sungai Kakap estuary
Based on the physical characteristic, Sungai Kakap estuary is an open estuary. This estuary is always influenced by sea water. This estuary receives fresh water
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21 from Sungai Kakap River, Sungai Punggur Kecil River and Sungai Punggur Besar River. The mouth of estuary is 987 meters with total area is about 13.5 km2. The salinity of this estuary is 5‰ to 7‰, water dept 2.5 meters and water transparency 20 cm. The bottom sediment of estuary is grumosol soil from marine sediment and it was affected by calcium formation. Sungai Kakap estuary is surrounded by mangrove forest. They are Nipah (Nypa fruticans) and Berembang (Sonneratia caseolaris). This estuary ecosystem is habitat for some fauna such as; fish, shrimp, sea bird, eagle, crocodile, monkey, snake, and bees. Fig.12 describe estuary condition and fisherman activity
Fig. 12: Profile of Sungai Kakap estuary
Sungai Kakap estuary has high potency of fishery resources but it is also vulnerable from human activities such as; agriculture, fish processing industries, gas station, catch landing, fish auction hall, workshop, docking, water transportation and other economic activities.
Fishery activity is the dominant than others in this estuary. Fishing gears used by fisherman are setnet, gillnet, trap, longline, belat, rompong and cas net. The species of shrimp and fish caught by fishermen from Sungai Kakap estuary are showed in Table 3.
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Table 3: The species of shrimp and fish caught by fisherman from Sungai Kakap estuary
No Local Name Common name Scientific name Type of gear
1 Udang galah Giant freshwater prawn Macrobrachium
rosenbergii
Trap, cas net, hook 2 Udang ambai Small white shrimp Metapenaeus lyssianassa Setnet 3 Udang tanduk Spider prawn Nematopalaemon tenuipes Setnet, casnet, trap 4 Udang bajang Yellow white shrimp Metapenaeus brevicornis Setnet, trap 5 Udang gantung Roshna prawn Exopalaemon styliferus Setnet, casnet 6 Udang bulan Hunter shrimp Exhippolysmata ensirostris Setnet, casnet 7 Teri Spotty face anchovy Stolephorus waitei Setnet, casnet
8 Anak ikan - - Setnet, casnet
Ikan lidah Doublelined tonguefish Paraplagusia bilineata Setnet 9 Belanak Largescale mullet Chelon macrolepis Giilnet,trap 10 Sembilang Striped eel catfish Plotosus lineatus Gillnet, hook 10 Serinding Buru glass perchlet Ambassis buruensis Setnet, casnet 11 Gulamah Sharpnose hammer
croaker Johnius borneensis Gillnet, hook,trap 12 Patin Catfish sp Pangasius spp Hook, gill net 13 Tappah Giant river catfish Wallago maculatus Hook, gill net 14 Baung Green catfish Mystus planiceps Gill net,hook 15 Lais Krytopterus bichirrhis Claris spp Giil net, hook 16 Kepiting
Bakau Mud crab Scylla serrata Trap
Fisherman organization
To accommodate fishermen aspiration, idea and change information, some fisherman founded organization. In Kecamatan Sungai Kakap at least there are five fisherman organizations (Table 4).
Table 4: Fishermen organization in Kecamatan Sungai Kakap Member
No Name Leader
(person) Location
1 HNSI Sungai Kakap Kasim Bakar 550 Sungai Kakap Village 2 Nirwana Iddris Mahmud 15 Tanjung Saleh Village 3 Teluk Harapan Darmawan 15 Tanjung Saleh Village 4 Lintang Jaya Hussin 14 Sungai Kakap Village 5 Lina Sederhana Lina 15 Sungai Kakap Village
Source: Fisheries and Marine Agency of Kecamatan Sungai Kakap, 2006
Supporting facilities for fisherman
The main supporting facilities for fisherman activities built by government and private sector are described in Table 5.
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Table 5: Supporting facilities for fisherman in Kecamatan Sungai Kakap Facility type Facilities number
(Unit) Funded by
1. Catch Landing Base
• Pier
• Auction hall
• Workshop
• Docking
• Gas station
• Fish traditional market
• Ice factory
• Cold storage
• Drying fish place
1 1 1 4 5 1 1 2 1 4
Government Government Government
Government and private sector Government and private sector Government and private sector
Private sector Government Private sector Private sector Private sector
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RESULTS
The numbers of small white shrimp (Metapenaeus lyssianassa) caught by setnet
During the study the numbers of small white shrimp caught by setnet is different from station to station. Higher numbers of the shrimp come from station V – X in the inner of estuary and the lower numbers come from stations I – IV in the river and station XI in the outer of the estuary (Appendix 3). The numbers of small white shrimp caught by setnet at each station is shown in Fig.13.
0 5 10 15 20 25 30 35 40 45 50
I II III IV V VI VII VIII IX X XI
Stations
Nu
m
b
e
r
Fig. 13: The number of small white shrimp caught at stations
Figure 13 can also show the spatial distribution of small white shrimp in Sungai Kakap estuary. The shrimp distribution could be influenced by aquatic environment condition, in this case caused by different salinity. According to Hilbron and Walters (1992) fisheries resources are not spatially homogeneous. Densities of fisheries resource are higher in some areas than others.
According to Macia (2004), some environmetal parameters that influence the shrimp distribution in coastal areas are salinity, temperature, turbidity and water depth. In this study correlation between salinity and the numbers of shrimp catches is relatively high. This information is shown in Fig.14.
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25
0 10 20 30 40 50 60
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99
day obse rv ation
s
al
in
it
y
a
n
d
cat
ch
vo
lu
m
catch salinity
Fig. 14: The relationship between shrimp catches and water salinity
Figure 14 show that small white shrimp can tolerate the salinity between 1‰ - 20‰. However this shrimp is preferable at salinity 5‰ – 7‰ (Appendix 4). The salinity distribution in the estuary of Sungai Kakap is described in Fig.15.
Fig.15. Water salinity distribution in Sungai Kakap estuary Kabupaten Pontianak West Kalimantan
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The carapace length of small white shrimp caught by setnet is described in the
Fig.16. The size range of this shrimp has carapace length between from 0.8 cm to 2.1 cm (Appendix 5 and 6). The bigger proportions of this shrimp were composed by carapace length from 1.3 – 1.5 cm.
13 May 2006 n = 189
0 50 100 150
0.8 - 1.2 1.3 - 1.5 1.6 - 1.8 1.9 - 2.1
Carapace length (cm )
S h ri mp n u mb e rs
13 M ay 2006 n = 268
0 50 100 150 200
0.8 - 1.2 1.3 - 1.5 1.6 - 1.8 1.9 - 2.1
Carapace le ngth (cm )
S h ri m p num be rs
10 June 2006 n = 189
0 50 100 150 200
0.8 - 1.2 1.3 - 1.5 1.6 - 1.8 1.9 - 2.1
Carapace length (cm )
S h ri mp n u mb e rs
Fig.16. Carapace length frequency distribution of small white shrimp caught by setnet, April – June 2006
Sizes distribution of small white shrimp caught by setnet
The sizes distribution of small white shrimp caught by setnet is described in the Fig.17. The average total length of small white shrimp in the river water (station 1 – 4) ranged from 4.4 cm – 4.9 cm or smaller than the average length total length of small white shrimp that inhabited in the inner of estuary water (station 5 – 10) which
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27 had average of total length 4.9 cm – 5.3 cm. The longest of total length was caught from deeper water with higher salinity (station 11), i.e. 6.8 cm. A specimen with total length of 9 cm was found also at station 11(Appendix 7).
0.00 5.00 10.00 15.00 20.00 25.00
I II III IV V VI VII VIII IX X XI
Station Tot a l l e ngt h, W a te r de pt h , s a li ni ty Shrim p length (Cm ) Water depth (m ) Salinity
Fig. 17: The average total length of small white shrimp caught by setnet in Sungai Kakap estuary compared with water depth and salinity.
The bottom sediment of the estuary consists of sand, clay and silt. The result of sediment analysis form laboratory is shown in Table 6.
Table 6: Sediment type in Sungai Kakap estuary
Result in %
Station 1 Station 3 Station 6 Station 10 Analysis type
( river ) ( river ) ( estuary ) ( estuary )
Unit
Sediment texture
Sand 11.4 13.2 17.4 18.4 %
Clay 56.2 40.7 33.4 35.7 %
Silt 32.4 46.1 49.2 45.9 %
From: Laboratory of Balai Besar Penelitian dan Pengembangan Pertanian, 2006
Setnet distribution
The operation of setnet in Sungai Kakap estuary was used more than twelve years ago. This gear is cheap and simple to operate. In addition the deployment of setnet relatively does not disturb for small fisherman boats. The numbers of setnet in Sungai Kakap estuary when the study conducted are 123 units. The distribution of setnet is illustrated in Fig. 18.
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Fig.18. Setnet distribution in Sungai Kakap estuary Kabupaten Pontianak West Kalimantan
Catch per unit effort (CPUE) of small white shrimp fishery
The catches of small white shrimp landed in Sungai Kakap landing base tend to increase during twelve years. This might be influenced by the increasing of fisherman efforts. However, the increasing of shrimp production does not always reflect the increasing of fisherman productivity. The trend of CPUE has been long time used to express the productivity of fishermen (Berachi 2003). CPUE trend of small white shrimp is expressed in Table 7 and Fig. 19.
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Table 7. Annual trend of small white shrimp catch and CPUE during 1994 – 2005
Catch Effort CPUE CPUE Effort No Year
(Kg) (trip) (Kg / trip) INDEX INDEX
1 1994 340330 10750 31.66 100 100
2 1995 378847 11370 33.32 108 108
3 1996 386142 12508 30.87 122 122
4 1997 330856 13693 24.16 100 124
5 1998 315067 17875 17.63 104 138
6 1999 311652 22836 13.65 102 139
7 2000 337561 22896 14.74 97 147
8 2001 415247 25879 16.05 97 159
9 2002 429978 27986 15.36 84 189
10 2003 439878 29896 14.71 51 292
11 2004 439012 29987 14.64 74 229
12 2005 438802 32895 13.34 66 297
Amount 4563372 258571 240.13 1105 2044 Average 380281 21548 20.01 92.08 170.33
CPUE Tre nd of am bai Shrim p
0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Ye ar
Kg
/
E
Fig.19.The CPUE trend during twelve years from the year 1994 - 2005
Figure 19 indicates that CPUE trend of small white shrimp tend to decrease over the years. One factor behind the condition could be the increasing effort by fisherman. The curve in Fig.20 illustrated the correlation between effort and CPUE of small white shrimp during twelve years as follow:
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30
0 50 100 150 200 250 300 350
1994 1996 1998 2000 2002 2004
Ye ar
In
d
ex val
u
e
CPUE INDEX
EFFORT INDEX
Fig.20. The correlation between effort and CPUE of small white shrimp in Sungai Kakap estuary
Figure 20 expresses the relation between CPUE of small white shrimp and effort numbers during the year 1994 - 2005. The curve shows that the increasing of effort numbers tended to be followed by decreasing of CPUE values.
Economic analysis of small white shrimp (Metapenaeus lysianassa) fishery
Fisherman income using setnet in Sungai Kakap estuary is derived from selling of small white shrimp production. Most of small white shrimp catches from Sungai Kakap estuary are sold by local market in Kecamatan Sungai Kakap. Most of small white shrimp is consumed by local community for fresh food and dry shrimp. Dry shrimp is marketed to wider market. They are sold to Jakarta and Sarawak Malaysia via middle man trader. The average price of fresh small white shrimp per kilogram in local market at the momment is Rp.6000 while dry shrimp price per kg is Rp.60000. Fisherman income per trip is derived from selling of shrimp production after it is lessened by total cost per trip. Total cost consists of variable cost (operational cost) and fixed cost (depreciation cost of fishing gear). The average of operational cost per trip is Rp.34.400 and the depreciation cost of fishing gear is Rp.13000 per trip or equal with total cost per trip Rp.47400 (Appendix 13 and 14). The average of fisherman income from small white shrimp fishery during three months investigation is shown in Table 8.
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Table 8: The average of fisherman income from small white shrimp fishery
Harvest Price Total Cost Gross
income Net Income
Year 2006
(Kg/trip) (Rp/Kg) (Rp) (Rp) (Rp)
April 12 6000 47400 72000 24600
May 10.5 6000 47400 63000 15600
June 14 6000 47400 84000 36600
Average
(April-June) 12.17 6000 47400 73000 25600
Table 8 shows that the average of fisherman income per trip was Rp.25600. The influence of fluctuation of shrimp production to the average of fisherman income might be caused by catching season of small white shrimp fishery in this estuary which is not stable every year. Based on field investigation, peak season of small white shrimp fishery in Sungai Kakap estuary occurs in August (Appendix 17
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DISCUSSION
The numbers of small white shrimp (Metapenaeus lyssianassa) caught by setnet
The individual numbers of small white shrimp caught by setnet in this site showed different results. According to sampling position the shrimp caught were high at stations close to the mangrove forest while shrimp caught away from the mangrove forest in the river and in the outer of estuary were low. Mangrove forest contributes to increase the amount of nutrient by falling leaf (Primavera, 1997). In fact the mangrove forest is supposed to influence the abundance of shrimp in the water and the roots of mangrove forest give shelter for shrimp from predator. The most abundance of mangrove forest in this estuary are nipah (Nypa frutican) and berembang (Sonneratia caseolaris). The mangrove forest area in this estuary is more than 40 ha. However, in several places mangrove forest is cut by local community for house construction and setnet. According to Castaneda and Defeo (2003) vegetated habitats are important in determining the distribution of penaeids in estuary, because they provide food and refugee from predators. Mangrove ecosystem is a suitable feeding, breeding, and nursery ground for various marine, estuarine and freshwater fishery resources (Hossain 2001).
Based on the salinity, the number of shrimp caught in Sungai Kakap estuary can be grouped into three. The first group was caught in the water salinity between 1 – 2‰, the second group was caught in the water salinity between 5 – 7‰ and the third group was caught in the water salinity 20‰. From this study small white shrimp is estimated to prefer staying in the water salinity between 5 – 7‰. According to Suseelan (1978) salinity is a limiting factor in the growth of most marine prawn species both directly and indirectly. Suseelan (1978) give example that
Penaeus indicus prefers the minimum of salinity 4‰, Penaeus semisulcatus prefers the minimum of salinity 19‰, Metapenaeus affinis and Metapenaeus dobsoni prefer the minimum of salinity 14‰, Parapenaeus stylifera prefers the minimum of salinity 25‰, Penaeus aztecus prefers the minimum of salinity 8.5‰.
The salinity distribution in the estuary and in the river influences to the distribution of small white shrimp (Metapenaeus lysianassa). In this study small white shrimp (Metapenaeus lysianassa) was found in around 4 km from coastal water to the river. This fact is supported by study of Azis (1979) that M. bennettae
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33 interval 0.4 – 10.7‰. Furthermore Munro in the year 1975 found P. merguiensis in Norman River with salinity 0.46‰ in the distance 80 km from coastal water (Azis at al 1983).
The carapace length of small white shrimp caught was analyzed by ANOVA. The F statistic result is 1.09 < F critical value 5.14 (Appendix 6). This indicates that the sizes of shrimp caught have no different. Range sizes of small white shrimp caught by setnet were from carapace length 0.8 cm – 2.1 cm. The most of shrimp caught were from carapace length 1.3 – 1.5 cm. The fact found that the bigger sizes of shrimp are not in abundance. According to Berachi (2003) one of overfishing symptom could be learned from a tendency to catch smaller sizes of shrimp individually over the year. Learning from range sizes of the shrimp caught by setnet which was composed from smaller sizes of the shrimp, it might warn that small white shrimp population in this estuary is declining.
Sizes distribution of small white shrimp caught by setnet
During the study the bigger sizes of shrimp caught were found in higher salinity in deeper water. While smaller sizes of the shrimp caught were from the lower salinity area. The factor might influence to distribution of smaller sizes of shrimp is water current. According to Macia (2004) one factor that may contribute largely to the pattern of distribution of smaller sizes in near proximity to mangroves could also be the water current.
The correlation analysis between salinity and small white shrimp is positive. The result of correlation analysis showed that r statistic of shrimp sizes – water salinity 0.89** and r statistic of shrimp sizes – water dept 0.86** (Appendix 8). It means that water salinity and water dept have positive correlation with the sizes distribution of small white shrimp in this estuary. There is an indication that adult small white shrimp prefer to inhabit in deeper water with salinity interval 10 – 20‰ in front of the mouth of estuary or in coastal water. Water spaces with salinity interval 10 – 20‰ generally is used by artisanal fishermen using setnet for fish and gillnet.
According to fisherman the dominant shrimp species caught by trawlers in the surrounding of Sungai Kakap marine waters with salinity more than 20‰ are yellow shrimp (Metapenaeus brevicornis), greasbaek shrimp (Metapenaeus ensis), red shrimp (Solenocera subnuda) and white shrimp (Penaeus indicus). But in several cases trawlers sometime enter in coastal water with salinity 10 – 20‰ primary at the
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34 night found small white shrimp (Metapenaeus lysianassa) in the limited numbers. Penaeid shrimp production from trawlers with tonnage from 5 – 20 gross tones landed in catch landing base of Sungai Kakap in the year 2005 were yellow shrimp (Metapenaeus brevicornis) 273610 kg, greasbaek shrimp (Metapenaeus ensis) 264830 kg, red shrimp (Solenocera subnuda) 226812 kg, and white shrimp (Penaeus indicus) 180720 kg ( Marine and fisheries agency of Sungai Kakap 2005).
The dominant bottom sediment of Sungai Kakap estuary is silt and clay. The percentage of sand content is increasing according to the distance of shore line. From the distribution of shrimp caught, it is supposed that silt and clay is preferred by small white shrimp (Metapenaeus lysianassa). The abundance of small white shrimp (Metapenaeus lysianassa) in silt and clay sediment might be influenced by their behavior to burry inside the estuary sediment beside there is enough availability of nutrient for shrimp. According to Ruello in Aziz (1983) the sizes of sediment texture less than 63 micron content high organic material (13.2%).
The study conducted by Aziz at al (1983) in Banten Bay showed that small white shrimp also was abundance in silt and clay sediment area. Furthermore Azis at al (1983) noted that other penaeid shrimps were found in different abundances in different sediment textures. P. monodon was not caught in sand and silt sediment but it was found in abundances in smooth silt and mud sediment. P. merguiensis was found in similar abundances in sand and silt sediment and it was found in silt and mud sediment. In addition Macia (2004) also noted that Fenneropenaeus indicus was found in abundance in sandy mud sediment but it was scarce found in mud sediment and Metapeaeus monoceros was found in abundance in mud sediment but it was scarce found in sandy mud sediment.
The sedimentation process in this estuary can threat the existence of small white shrimp habitat. It may be caused by mangrove cutting and the upland activities. The sedimentation might increase the water turbidity. At the moment the average of water transparency in the estuary is around 20 cm. The water transparency decreases along the river. The decreasing of water transparency might be caused by increasing of suspended material in the water column such as clay, sand, organic material and the others. Indirectly water transparency influences to water productivity. Decreasing of water transparency might decrease sunlight penetration to water column. Sunlight is needed by phytoplankton and water vegetation for photosynthesis process. Therefore water productivity could be decreased by sedimentation. For example from field investigation that the numbers of wood trap deployed in estuary water for
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35 trapping giant fresh water shrimp (Macrobacium rosenbergii) are 200 units. Most of wood traps are from mangrove plant. The requirement of mangrove plant for one unit wood trap is in about 600 stick or equal with two of mangrove plants per unit or 400 of mangrove plants for the total of wood traps deployed in this estuary for one season or six months operation. The threat of mangrove cutting in this site could cause land erosion and it might change sediment texture and harm aquatic organism in the estuary.
Setnet distribution
To manage the setnet in this estuary it is important to have map. In the moment there is no spatial planning for setnet in this estuary. Map of setnet distribution is look like unmanaged and there is not sit line for water transportation. Therefore, the position of setnet should be regulated.
Catch per unit effort (CPUE) of small white shrimp fishery
The CPUE of small white shrimp tends to decrease from year to year. Decreasing of CPUE might be influenced by the increasing of fishing efforts. The
result of correlation analysis between CPUE and effort shows that r statistic (- 0.82**) was bigger than r table, this means that the increasing of effort numbers
has high negative correlation to CPUE values (Appendix 12).
According to Berachi (2003) the decreassing of CPUE, a tendency to catch more small sized individuals, a change in catch composition can be used to see overfishing symptom. However decreasing CPUE of small white shrimp caught by setnet in Sungai Kakap estuary might be important information to manage small white fishery.
The factors might decrease CPUE of small white shrimp in Sungai Kakap estuary estimated from several factors such as:
1) The increasing of effort numbers to catch small white shrimp and employment in higher levels in line with the increasing coastal population, poorness, lack skill and education and also lack mechanization to exploit the offshore fisheries resources have triggered overexploitation of fisheries resources in inshore fisheries which relatively has cheaper infestation and cheaper operational cost. The regulation on the limitation of effort numbers might become one factor to recover sustainability of small white shrimp in this estuary.
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38
DEDICATION
TO
My mother, Restinem and my father, Darmuji who have mothered, educated, guided and prayed so that I have better position and better education
And TO
My sons, Rachmadanu Fitra Panutan and Safli Bayu Prakarsa who always give inspiration and reflect my future and my wife, Desi Kartika who has acompanied
patiently and given moral support during the study
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