Shrimps Caught by Set Net in Different Mangrove Conditions in the Estuary of Sungai Kakap, West Kalimantan
SHRIMPS CAUGHT BY SET NET IN DIFFERENT
MANGROVE CONDITIONS IN THE ESTUARY
OF SUNGAI KAKAP, WEST KALIMANTAN
MACHMUD
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2006
THESIS STATEMENT AND INFORMATION SOURCES
Hereby I declare that thesis of Shrimps Caught by Set Net in Different Mangrove
Conditions in the Estuary of Sungai Kakap, West Kalimantan is my own casing, and that
no part of whole thesis has been printed or published in other universities yet. The
information sources cited from other authors were mentioned in the text and in the
references.
Bogor, September 2006
Machmud
NRP. C251040334
ABSTRACT
MACHMUD. Shrimps Caught by Set Net in Different Mangrove Conditions in the
Estuary of Sungai Kakap, West Kalimantan. Under supervision of UNGGUL AKTANI,
AGUSTINUS M. SAMOSIR, and ARIO DAMAR.
Mangrove ecosystem provides many benefits to local people both ecologically and
economically. Unfortunately, the mangrove forest has been degraded, due to the
increasing pressures of anthropogenic activities. Consequently, it would diminish most of
the life supported by mangrove, and threaten the security of local people livelihood. This
research was carried out to study the influence of mangrove plant conditions on shrimp
catches in set nets and how this contribute to local management plan. The method applied
for mangrove was transect line, and shrimps were collected with set net, and then they
were related each other to analyze the influences. This study showed that links between
mangrove plant conditions (area, density and coverage) and shrimp catch total and
carapace length give positive regression. Significant positive correlations are shown by the
relationship between percentage of mangrove area and number of Udang Ambai
(Metapenaeus lysianassa) with 1.0-1.5 cm carapace length with a simple linear regression
equation Y=23.5+0.3X (R²=0.62). The communities depend on mangroves and lives
supported by them, though the people were not found very aware about ecology, functions,
and threats of these resources. Therefore, the community involvement on the management
of mangrove ecosystem and shrimp catch is required. Zoning through the participation of
community is regarded as a major tool to achieve the goal of sustainable use of coastal
resources.
ABSTRAK
MACHMUD. Udang yang Ditangkap dengan Set Net (Ambai) pada Kondisi Mangrove
yang Berbeda di Estuari Sungai Kakap, Kalimantan Barat. Dibimbing oleh UNGGUL
AKTANI, AGUS TINUS M. SAMOSIR, dan ARIO DAMAR.
Ekosistem mangrove memiliki manfaat baik secara ekologi maupun ekonomi bagi
kehidupan masyarakat lokal. Namun dengan meningkatnya aktivitas manusia, hutan
mangrove mengalami degradasi yang akan menyebabkan menurunnya berbagai kehidupan
yang ditopang oleh keberadaan ekosistem tersebut, dan akan mengancam pada mata
pencaharian masyarakat lokal. Tujuan penelitian ini adalah untuk mengkaji pengaruh
kondisi tanaman mangrove pada penangkapan udang di dalam set net dan kontribusinya
terhadap perencanaan pengelolaaannya. Metode yang digunakan untuk mangrove adalah
transek garis, dan udang ditangkap menggunakan set net (ambai), dan kemudian
dihubungkan satu sama lain untuk menganalsis pengaruhnya. Hasil studi ini menunjukkan
bahwa hubungan kondisi tanaman mangrove (luas, kerapatan dan penutupan) dan
tangkapan udang total dan panjang carapace memberikan regresi yang positif. Persentase
luas mangrove terhadap jumlah Udang Ambai (Metapenaeus lysianassa) dengan panjang
carapace 1.0-1.5 cm memberikan pengaruh positive yang paling nyata dengan persamaan
regresi linear sederhana Y=23.5+0.3X (R²=0.62). Masyarakat dan beberapa kehidupan
tergantung pada mangrove, akan tetapi sebagian besar masyarakat belum begitu peduli
mengenai ekologi, fungsi dan ancaman terhadap sumberdaya tersebut. Untuk itu,
keterlibatab masyarakat pada pengelolaan ekosistem mangrove dan tangkapan udang
diperlukan. Zonasi melalui partisipasi masyarakat dipandang sebagai alat utama dalam
mencapai tujuan pemanfaatan sumberdaya pesisir secara berkelanjutan.
© Copyright property is owned by Machmud, 2006
All rights reserved
This thesis or parts thereof may not be reproduced in any form without written consent
from Bogor Agricultural University (IPB)
SHRIMPS CAUGHT BY SET NET IN DIFFERENT
MANGROVE CONDITIONS IN THE ESTUARY
OF SUNGAI KAKAP, WEST KALIMANTAN
MACHMUD
Thesis
as a partial fulfillment for Master Science Degree
in Marine and Coastal Resources Management
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2006
Thesis Title
Name
Register Number
: Shrimps Caught by Set Net in Different Mangrove Conditions in the
Estuary of Sungai Kakap, West Kalimantan
: Machmud
: C251040334
Approved by Advisory Board
Dr. Unggul Aktani
Supervisor
Ir. Agustinus M. Samosir, M.Phil.
Co-supervisor
Dr. Ir. Ario Damar, M.Si.
Co-supervisor
Acknowledged by
Head of Study Program
Dean of Post Graduate School
Prof. Dr. Ir. Rokhmin Dahuri, M.S.
Dr. Ir. Khairil Anwar Notodiputro, M.S.
Date of examination: September 25th , 2006
Approved on:
PREFACE
Hereby I would like to give thankfulness God who has been giving its blessing to
me, so I could complete my thesis with title Shrimps Caught by Set Net in Different
Mangrove Conditions in the Estuary of Sungai Kakap, West Kalimantan. This thesis is as
a partial fulfillment for master science degree in Coastal and Marine Resources
Management Study Program.
I acknowledge the Marine and Coastal Resources Management Project at Marine
Affair and Fisheries for providing a scholarship of Sandwich Master Degree Program in
Bogor Agricultural University and Aarhus University-Denmark.
I also thank all persons for supporting to complete my thesis and to finish this study
program, namely:
1. Dr.Unggul Aktani, Ir. Agustinus M. Samosir, M.Phil and Dr. Ir. Ario Damar, M.Si as
my supervisors who gave tuition, advices, and guidance to complete from proposal
research to thesis.
2. Ir. Ki Agus Abdul Azis, M.Sc as a guess examiner and Dr. Ir. Mennofatria Boer, DEA
as a academic commission examiner for giving corrections and suggestions to improve
this thesis.
3. 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 for facilitating
the need of sandwich students during study.
4. Prof. Vibeke Simonsen and Prof. Mogens from Aarhus University Denmark who gave
suggestions and guidance in my minor thesis composing during the study in Aarhus
University, Denmark
5. Mr. Hardiono and staff from Fisheries Resort of Sungai Kakap for assisting during data
collection.
6. My colleagues in post graduate sandwich program; Zainal, Zaitul, Efrizal, Saptoyo,
Edo, Coki, Kusdiantoro, Neti, Normawati, Yesi, and Eiren for cooperation, friendship,
support, and advices during study.
7. All relations who could not be mentioned individually for their assistances and
cooperation.
Finally, I hope this thesis can give benefits to every one who need it.
.
Bogor, September 2006
Machmud
BIOGRAPHY OF AUTHOR
The author was born in Sumedang West Java on 08
January 1973 from the couple of H.Odjo, BA and Hj. Runasih,
and the youngest from four brothers.
In 1992, the author was graduated from Senior High
School (SMAN 2 Sumedang), and in 1997 the author was
graduated from Bogor Agricultural University (Institut Pertanian
Bogor) with Program Study of Agricultural Economic and
Resources, Socia l Economic Departement, Faculty of Agriculture.
In 2004, the author got schoolarship of Sandwich Master
Degree Program in Bogor Agricultural University and Aarhus
University-Denmark provided by Marine and Coastal Resources
Management Project (MCRMP) at Ministry of Marine Affair and Fisheries.
The author is a government employee, from 1998 to 2003 he had been working in
Ministry of Agriculture Jakarta, and from 2003 to day he have been working in Ministry of
Marine Affair and Fisheries Jakarta.
In 1996, the author has merried Nurul Quddusy, SP, and they have four children,
three sons (Sulthon Kamel, Tsamada Akhsani, Dhia Zaidan) and one daughter (Izatannisa
Nurma Ramadhani).
DEDICATION
TO
My mother, Hj. Runasih and my father, H. Odjo, BA who have mothered, educated, guided
and prayed.
And
TO
My wife, Nurul Quddusy, SP for her unfailing love, support and prayer, and to
our children, Sulthon Kamel, Izatannisa Nurma Ramadhani, Tsamada Akhsani, and Dhia
Zaidan who always give prayers and inspirations
TABLE OF CONTENTS
Pages
LIST OF TABLES .............................................................................................
xi
LIST OF FIGURES ............................................................................................
xii
LIST OF APPENDIXS ......................................................................................
xiv
INTRODUCTION ..............................................................................................
Background .................................................................................................
Hypothesis ........ .........................................................................................
Objectives ....................................................................................................
Advantages ..................................................................................................
1
1
2
2
2
LITERATURE REVIEWS ................................................................................
Mangrove ....................................................................................................
Shrimps .......................................................................................................
Relationship between Mangrove and Shrimps ...........................................
Management of Mangrove and Shrimp Catches ...……………………….
3
3
4
5
7
METHODS …………….....................................................................................
Research Framework …..............................................................................
Study Area ...................................................................................................
Data Collections ..........................................................................................
Mangrove ..............................................................................................
Shrimps .................................................................................................
Data Analyses ..............................................................................................
10
10
10
12
12
13
14
RESULT AND DISCUSSION ...........................................................................
Result ..........................................................................................................
Mangrove Conditions in the Estuary of Sungai Kakap……..................
Set Net Fishery in the Estuary of Sungai Kakap ...................................
Relationship between Mangrove and Shrimp Catches .........................
Discussion ...................................................................................................
Relationship between Mangrove and Shrimp in the Estuary of Sungai
Kakap ...................................................................................................
Management of Mangrove and Set Net Fishery....................................
18
18
18
19
21
27
CONCLUSION AND RECOMMENDATION .................................................
Conclusion ……………………........................................................
Recommendation ………………………………..…...........................
34
34
34
REFERENCE .....................................................................................................
35
APPENDIXES ...................................................................................................
39
27
30
LIST OF TABLES
Pages
1
The kinds of mangrove data, procedures, and equipments conducted
during sampling in the estuary of Sungai Kakap, 2006 ...............................
13
2
The kinds of shrimp data, procedures, and equipments conducted during
sampling in the estuary of Sungai Kakap, 2006 ...........................................
13
3
A design of regression with more than value of Y (shrimp catches) per
value of X (mangrove condition) with equal sample sizes ..........................
17
4
The present covering of mangrove area in the estuary of Sungai Kakap,
2006 ………………………………………………………………………..
18
5
Share of species to total shrimp abundance in six different stations (ST),
the estuary of Sungai Kakap, 2006................................................................
20
6
(
)
Distribution mean x ± SE of individual shrimp numbers per set net in six
different stations, the estuary of Sungai Kakap, 2006 ..................................
20
LIST OF FIGURES
Pages
1
The life cycle of penaeid shrimps (Masrtosudarmo and
Ranoemihardjo, 1979 in Eidman et al., 1983) ........................................
4
2
The research framework of the influence of mangrove conditions on
shrimp catches in set nets .......................................................................
10
3
A map of Sungai Kakap Sub District, Pontianak District, West
Kalimantan .............................................................................................
11
4
Schematic representation of sampling for mangroves and shrimp
catches in the set nets in the estuary of Sungai Kakap .........................
12
5
The density, coverage and important value of mangroves in six
different stations, the estuary of Sungai Kakap, 2006 ............................
19
6
(
)
Distribution mean x ± SE of M. lysianassa numbers with 1.0-1.5 cm
CL and 1.6-2.0 cm CL in six different stations, the estuary of Sungai
Kakap, 2006 …………………………………………………………...
21
The regression line and equation between percentage of mangrove
area (S. caseolaris and N. fruticans) and individual number of shrimp
catches …………………………………………………………………
22
The regression line and equation between percentage of mangrove
area (S. caseolaris and N. fruticans) and individual number of M.
lysianassa (1.0-1.5 cm CL) ……………………………………………
23
9
The regression line and equation between density of S. caseolaris and
individual number of shrimp catches ………………………………….
23
10
The regression line and equation between density of S. caseolaris and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
24
The regression line and equation between density of N.fruticans and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
24
12
The regression line and equation between coverage of S. caseolaris
and individual number of shrimp catches ……………………………..
25
13
The regression line and equation between coverage of S. caseolaris
and individual number of M. lysianassa (1.0-1.5 cm CL) …………….
25
14
The regression line and equation between coverage of N.fruticans and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
25
15
The regression line and equation between Important Value of S.
caseolaris and individual number of shrimps …………………………
26
7
8
11
16
17
18
The regression line and equation between Important Value of S.
caseolaris and individual number of M. lysianassa (1.0-1.5 cm CL) …
26
The regression line and equation between Important Value of
N.fruticans and individual number of M. lysianassa (1.0-1.5 cm CL) ..
26
Zonings for land use planning of a mangrove and shrimp catch
management in the estuary of Sungai Kakap, 2006 ...............................
31
LIST OF APPENDIXES
Pages
1
The Population of Sungai Kakap Subdistrict, 2003 ...............................
39
2
Physical parameters during sampling study in the estuary of Sungai
Kakap, 2006 ...........................................................................................
40
3
A set net fixed to sample shrimps in the estuary of Sungai Kakap .......
42
4
The features of “Berembang” (local name) in the estuary of Sungai
Kakap, 2006 ...........................................................................................
43
5
The features of “Udang Ambai”, “Udang Bajang”, “Udang Bulan”,
“Udang Gantung” and “Udang Galah” (local name) in the estuary of
Sungai Kakap, 2006 ...............................................................................
44
6
(
)
Confidence limit of shrimp catches distribution x ± (t (df , 95% ) × SE ) or
x ± (1.96 × SE ) for six different stations in the estuary of Sungai
Kakap, 2006 ...........................................................................................
47
INTRODUCTION
Background
Mangrove ecosystem provides many benefits to local people, both ecologically
and economically. Especially since this ecosystem gives important sources of food
for incredible diverse lives, such as fishes, crabs, shrimps, prawns, and mollusks
(Choong et al., 1990; Snedaker, 2005). Many penaeid species spawn in offshore, but
they use mangroves as refuge and feeding grounds during later stages (Christensen,
1983). For instance, mangrove ecosystem in the estuary of Sungai Kakap has certain
benefits on local fisheries specifically on shrimp catches.
Unfortunately, the mangrove ecosystem in the estuary of Sungai Kakap has
been degraded, due to the increasing pressures of anthropogenic activities, such as
agricultural activities, infrast ructure and residential. Study of Sudara and Singkran
(2005) showed that mangrove degradation caused a decreasing in fish abundance and
species richness. Furthermore, Melana et al. (2000) have shown that for every
hectare of mangrove cut down, a corresponding reduction in fish catch is estimated to
be 1.08 tons per year. Thus, the mangrove degradation in Sungai Kakap would
threaten the shrimp catches in those areas, and finally impact the security of local
people livelihood.
These causal-effect relatio nships should be understood by all stakeholders and
adjusted by local government in making especially policy on coastal resources
management. According to FAO (1995) the success of the resources management
will be achieved if all people involved in the management strive to maintain or
restore the coastal ecosystem.
Based on this phenomenon, the problems of study are formulated:
1.
What are the present conditions of mangrove in Sungai Kakap?
2.
Do the mangrove conditions influence on shrimp catches in set nets in Sungai
Kakap?
Consequently, this study will deal with the mangrove conditions and the ir
influences on shrimp catches in set nets in the estuary of Sungai Kakap.
2
Hypothesis
The shrimp catches in set nets are influenced by the mangrove conditions .
Objectives
The objectives of this study are:
1.
To identify the characteristics and conditions of mangrove .
2.
To identify the characteristics and distributions of shrimps in set nets.
3.
To study the influence of mangrove conditions on shrimp catches in set nets.
4.
To recommend a management alternative of mangrove and set net fishery.
Advantages
The advantages of this study are:
1.
Academically, the study results are expected to enrich the education literatures,
especially on the influence of mangrove conditions on shrimp catches in set
nets, and able to become a source for next researchers to further studies.
2.
Practically, the study results are expected to have benefit for local government
in term of mangrove ecosystem and set net fishery management.
LITERATURE REVIEWS
Mangrove in estuary provides important roles on commercial fisheries specifically
for shrimp productions. On the other hand, the anthropogenic activity pressures, such as
residential and agricultural activities, cause damage to this ecosystem and can destroy the
fisheries. From this knowledge the people should be understood about the relationship
between the mangrove healtheness and fisheries production (Simonsen, 2005). This
chapter will review mangrove, shrimps, and the management.
Mangrove
The mangrove terminology is used to define both a group of plants and a habitat
type in the coastal zone (Spalding, 2001). Eventhough mangroves consist of a group of
plants from many different genera and families; they exhibit numerous similarities in
appearance, physiology, reproduction and adaptation to habitat (Osborne, 2000).
Mangroves can survive in high salinity conditions, extreme tides, strong winds, high
temperatures, muddy, and anaerobic soils (Kathiresan and Bingham, 2001). These
adaptations to extreme conditions will determine the patterns of zonation in mangrove
communities (Spalding, 2001).
According to Zamani (2005), in general the mangrove zonations are divided into
three zones, namely: seaward zone, landward zone, and transition zone. The seaward zone
is an area which is found in proximity to shallow marine systems with sandy substrates and
often dominated by Avicennia and usually associated with Sonneratia. The landward zone
positioned behind the seaward zone is an area in the swamps dominated by Rhizophora,
Bruguiera and Xylocarpus (Chapman, 1976 in Choong et al., 1990). And the transition
zone is an area which located between mangrove forest and low land terrestrial forest,
usually dominated by Nypa fruticans and several species of palm trees (Bengen, 2004).
Nypa fruticans is also mainly found along the channel margins in the upper and middle
reaches of South East Asian estuaries where the salinity is between 1‰ and 10‰
(Robertson et al., 1991 in Blaber, 1997).
In West Kalimantan, the mangrove vegetations as pioneer community are
dominated by Api-Api (Avicennia marina), bogem (Sonneratia caseolaris) or perepat
(Sonneratia alba). In the river banks are usually grown by Bakau (Rhizophora mucronata
and Rhizophora apiculata). The landward sides are dominated by Berus (Bruguiera
gymnorhiza) and nyirih (Xylocarpus granatum) combined with Bakau (Rhizophora
4
mucronata and Rhizophora apiculata), while Nipah (Nypa fruticans) thrive in river bank
and estuary (The Strategic Planning (“Renstra”) of West Kalimantan Province, 2003).
Shrimps
The shrimps are classified as class of Crustacean, order of Decapoda, and suborder
Natantia that are divided into three infraorders, Penaeidae, Caridea, and Stenopodidea
(Dore and Frimodt, 1987).
The infraorder of Panaeidae that included in the family
Penaeidae of the super- family Penaeoidea is the important commercial shrimps of marine
tropical and sub-tropical waters (Dall, 1981) that consist of two genuses, namely: Penaeus
and Metapenaeus (Naamin, 1979 in Eidman et al., 1983) and that include 110 species
(Holthis, 1980 in Eidman et al., 1983). For example, the important commercial shrimp in
the estuary of Sungai Kakap is Metapenaeus lysianassa (“Udang Ambai” in local name),
with the total production 438.8 tons in 2005 (Fishery and Marine Resort of Sungai Kakap
Sub District, 2006).
In nature, the penaeid shrimps have three kinds of life cycle involving shrimps live
in offshore, shrimps live in inshore, and shrimps live in both the waters (Kirkegaard, 1975
in Eidman et al., 1983). However, almost all the shrimp larvae, both freshwater and
seawater, need estuary for growing into juvenile (Martosudarmo and Ranoemihardjo, 1979
in Eidman et al., 1983; D’Abramo and Brunson, 1996). The juvenile of marine shrimps
tend to move into deeper waters in accordance growth, and the sexual maturity is usually
achieved in waters of oceanic salinity (Dall, 1981). Figure 1 describes the life cycle of
shrimps from eggs to adult shrimp and their habitats.
Figure 1 The life cycle of penaeid shrimps (Masrtosudarmo and Ranoemihardjo, 1979 in
Eidman et al., 1983).
The environmental parameters that influence the distribution of penaeid shrimps are
salinity, tidal current, substrate types, food sources, and refuge place for living and
growing (Dall, 1981). Mair (1980) showed that the preference for low salinity inland
5
water might be an important factor in the immigration of postlarval penaeid shrimp from
the sea to their nursery grounds, such as estuaries, bays, and coastal lagoons. Pearse &
Gunter (1957) in Mair (1980) noted that it was generally the younger or smaller stages of
animals which inhabit low salinities, and although there are some exceptions, this certainly
applies to the Penaeidae.
Chong et al. (1990) explained that the coastal mangroves and mud flats were
important nursery areas for commercially important prawn species belonging to the genera
Penaeus and Metapenaeus. Furthermore, Ronnback et al. (2002) showed that Penaeus
indicus had a significant prefe rence for fringe mangroves over the adjacent sand flat and
Metapenaeus monoceros was significantly more abundant in the sand flat than in the
mangrove fringe, although this habitat preference was not evident for juvenile and subadult life stages.
Additionally, Eidman et al. (1983) showed that the abundances of
Metapenaeus ensis and M. lysianassa were influenced by spring and low tide, but the
abundances of Penaeus monodon and P. merguiensis in Banten Bay were not influenced
by tidal inundation.
Relationship between Mangrove and Shrimps
Mangrove has an important role as nursery grounds, feeding grounds, and
spawning grounds for waters biotes (fishes, shrimps, crabs, molluscs, etc.) (Christensen,
1983; Choong et al. 1990; Baran and Hambrey, 1999; Kathiresan and Bingham, 2001;
Spalding, 2001; Dahuri et al., 2001; Adeel and Pomeroy, 2002; Dahuri, 2003; Gunarto,
2004; Bengen, 2005). Two main reasons why mangrove is important as habitat for aquatic
species are: (1) it provides abundance food for an incredible dive rsity of life, namely:
coastal and offshore marine communities (Choong et al., 1990; Clough et al., 1994;
Snedaker, 2005), (2) mangrove roots above and below the ground provide many different
kinds of habitats, where aquatic animals can live and shelter from predation (Christensen,
1983; Clough et al., 1994; Melana et al., 2000; Ronnback et al., 2002).
Many species of penaeid juveniles migrate into mangrove waterways where they
live for some time before moving back to offshore waters as they approach reproductive
maturity (Clough et al., 1994). Genera Penaeus and Metapenaeus spawn at sea and after a
few weeks the postlarval shrimps settle in inshore and estuarine waters (Dall et al., 1990 in
Ronnback et al., 2002), which they use as nurseries during their critical early life stages.
The structure and function of these nursery grounds are usually characterized and
6
influenced by the presence of vegetation like mangrove forests and seagrass beds
(Ronnback et al., 2002)
Penaeid shrimp species in the Indo-Pacific are reported to have a preference for
mangrove as nursery ground includ ing Penaeus indicus (Chong et al., 1990), P.
merguiensis (Vance et al., 1990 in Ronnback et al., 2002), P. monodon (de Freitas, 1986 in
Ronnback et al., 2002), and P. penicil-latus (Chong et al., 1990). Other penaeid shrimp
species are, however, not confined to mangrove habitats as nursery grounds. For instance,
P. duorarum (Sheridan, 1992 in Ronnback et al., 2002), P. esculentus and P. semisulcatus
(Robertson & Duke, 1987 in Ro nnback et al., 2002) seem to have a preference for
submerged macrophytes like seagrass and algal beds. Metapenaeus monoceros (de Freitas,
1986 in Ronnback et al., 2002) and M. ensis (Robertson & Duke, 1987 in Ronnback et al.,
2002) are more widespread, occurring on seagrasses, mud flats, mangrove channels, etc.
Yanez-Arancibia et al. (1985) in Baran and Hambrey (1999) explained that a clear
positive correlation was shown between commercial finfish catches and the total area of
coastal vegetation - mostly mangroves in the Gulf of Mexico. Still in this area, Turner
(1977) in Baran and Hambrey (1999) found a positive correlation between shrimp catches
and the vegetated surface area of estuaries. In addition, Martosubroto and Naamin (1977)
in Baran and Hambrey (1999), in Indonesia, showed a positive correlation between annual
catch of prawns and area of mangrove. Paw and Chua (1989) in Baran and Hambrey
(1999), found in the Philippines a positive correlation between mangrove area and penaeid
shrimp catch. Staples et al. (1985) in Baran and Hambrey (1999), in Australia found a
positive correlation between the total length of mangrove lined rivers and the annual catch
of banana prawns, and Pauly and Ingles (1986) in Baran and Hambrey (1999) showed that
most of the variance of the MSY (Maximum Sustainable Yield) of penaeids could be
explained by a combination of area of mangrove habitats. Furthermore, Melana et al.
(2000) have shown that for every hectare of mangrove cut down, a corresponding
reduction in fish catch per year.
Ronnback et al. (1999) have described that the faunal distribution patterns in open
water habitat dominated by mangrove community (Avicennia or Rhizophora) provide new
and valuable information for the assessment of the ecological value of mangroves for
fisheries production. Shrimps and fish utilize large parts of the mangrove forest during
spring tide. The density of shrimp community in mangrove area is expressed through the
highest density in the habitat with the highest structural complexity, and a small-sized fish
community.
Further, Ronnback et al. (2002) investigated that Penaeus indicus had a
7
significant preference for fringe mangroves over the adjacent sand flat, and there was no
correlation between shrimp abundance and organic content of sediment.
Whereas,
Metapenaeus monoceros was significantly, more abundant in the sand flat than in the
mangrove fringe. In addition, Eidman et al. (1983) showed that the distribution pattern of
shrimps follow the distribution pattern of mangrove (Avicennia sp), where the shrimp
abundances were less to upstream parallel with the richness of Avicennia species which
was also less to landward.
Management of Mangrove and Shrimp Catches
Management of mangrove ecosystems is an effort that should be done to prevent a
decrease of mangrove areas, so that the roles of this ecosystem can be sustainable to fulfill
the needs of the present without compromising the ability of future generations to meet
theirs (UN, 1987). The fundamental objective of mangrove ecosystem management is to
promote conservation, and where necessary restoration or rehabilitation and sustainable
use of mangrove ecosystems and their associated habitats to benefit local to global
populations (Macintosh and Ashton, 2005).
Identificatio n of existing condition of mangrove that based on the location,
ecological characteristics and values could be used to determine the preservation,
conservation or sustainable utilization areas.
The pristine mangrove forest should be
preserved or declared as forest reserves, while mangrove areas near or adjacent to known
habitats important as fish, mollusk and crustacean nurseries and/or fishing grounds should
not be alienated or released for development. Some mangrove areas in urban areas should
be conserved exclusively for sustainable utilization by the local people who should be
involved in any reforestation and maintenance efforts. Rehabilitating areas of destroyed
mangroves through natural regeneration, assisted if necessary by active intervention,
including restoration of the hydrological regime and/or planting mangroves. Mangroves on
small islands serve as a major ecological component of the island ecosystem and should in
no case be disturbed. Mangroves in estuarine areas should be protection zone areas of
mangroves preserved on the banks of the mouth of the river fronting the sea (Macintosh
and Ashton, 2005).
Fisheries that associated with mangrove conditions give importance food and
income for local communities. However, lack of enforcement of existing fishery
regulations, including lack of protection of mangrove nursery sites and habitat degradation
are among the major reasons for the widespread decline in mangrove fisheries. Full
8
attention should be taken to support the livelihoods of mangrove fishers, to promote
awareness of mangrove ecosystems, and to help local communities to adopt a sustainable
management of mangrove.
According to Centre of Research and Fisheries Development (1992) management
practice of shrimp resources should consider fisheries management strategic including size
control, allowable catch number, effort control, and selective fishing gear in order to get
the optimal and sustainable fisheries. A closing technique and fishing seasons are to
control the number and shrimp sizes. Allowable catch size can be carried out by mesh size
control so it can protect the young shrimps. Effort control is to prevent over fishing in
certain area through to create a new fishing ground in other places or to limit the number of
fishing effort wit h license restriction. While selective fishing gear is fishing gear, which
have been designed to exclude/reduce the capture of unwanted sizes and species of fish and
the incidental catch, and release these excluded fish from the fishing gear with a high
survival (FAO, 1995).
As a river buffer zone, mangrove areas in Sungai Kakap are managed by Forestry
Office (UU No 41 1999), while shrimp catches management is under Fishery Office,
especially for fishing licenses of all fishing gears operated and fee of fishery business.
Based on these regulations, the coordination between these institutions must be done to
ensure the application of management. According to FAO (1995) the success of this
management will be achieved if all people involved in this management strive to maintain
or restore the coastal ecosystem. Therefore, the sustainable ecosystem management can be
attained through community based management approaches that provide a sense of
belongings with full participation, cooperation and empowerment of the all involved
stakeholders
According to the Centre for Community- Based Resource Management (2005),
“Community- Based Resource Management (CBRM) is a development approach that
emphasizes the interconnectedness of humans and all other living beings and their natural
environment”. Therefore, the present people who live in an ecosystem have the most
important responsibility to control their activities in a way that promotes this renewal and
sustains resource abundance and environmental friendliness for future generations. In
addition, Klinger (2004) reports that an Integrated Coastal Zone Management (ICZM)
approach that has been proven successfully in the long term is a integration of whole
stakeholder participation to formulate socially acceptable solution to problems of
sustainable resource management in coastal zones. Further, Pomeroy (1995) explains that
9
the management will be better implemented and managed when the local communities (i.e.
fishermen) and other related stakeholders are more involved in the resources management
and the access rights are distributed more effectively and rightfully.
Community based management approaches require clear and well-organized
management policies from all the stakeholders. The policies should be developed with
cooperation of all groups that have an interest in coastal area, including the local
communities, local government (such as fisheries office, environmental office and forestry
office), center government (such as ministry of forestry, ministry of marine and fisheries),
NGO, and other interested organizations (Strategic Planning (“Renstra”) of West
Kalimantan Province, 2003). Adeel and Pomeroy (2002) explain that a management
policy to protect and conserve mangrove forests and to give a local livelihood security can
be valued by the worth and success of community based management approaches for
protection and conservation.
METHODS
Research Framework
The research framework of shrimps caught by set net in different mangrove
conditions in the estuary of Sungai Kakap is shown in Figure 2.
Figure 2 The research framework of shrimps caught by set net in different mangrove
conditions.
Study Area
Sungai Kakap is a sub district situated in the western part of Pontianak (22 km from
Pontianak City), West Kalimantan Province on the Borneo Island (0°03’15”N – 0°15’33” S
and 109° 4’ E - 109° 21’ E) (Figure 3). This study was performed in the estuary of Sungai
Kakap Sub District (0°03’00”S – 0°05’06” S and 109°09’36” E - 109°10’48” E (Figure 3).
The total area of site about 7.4 km², with 7 km long and around 1 km wide, and has 1-3 m
deep at the lower reaches during low tides. This estuary derived from several drainages
including Kakap River from the east, Pungur Kecil River and Pungur Besar River from the
south. The water front was surrounded by mangrove communities, which cover a further
area of 35.86 hectares. Landward, it was bounded by seven villages, namely: Tanjung
Saleh, Sungai Kakap, Sungai Belidak, Kalimas, Pungur Besar, Pungur Kecil and Sungai
Kupah (Figure 3), with a 2003 population reported to be 45,635 (51.5% of the total
11
population of Sungai Kakap Sub District) (Statistical Bureau of Pontianak District, 2003)
(Appendix 1).
E 109°07’1 2”
E 109 ° 08’24”
E 109°09’36”
E 109°10’48”
E 109°12’
E 109°11’12”
E 109°13’36”
E 109 ° 14’48”
SUNGAI KAKAP
SUB DISTRICT MAP
PONTIANAK REGENCY
WEST KALIMANTAN
Siantan Sub District
P. Panjang
0°
0°
E 109°12’24”
Jeruju Besar
S 0° 01’12”
S 0°01’12”
Kapuas River
South
Sea
West Chinese
Kalimantan
#
#
Sungai Kakap
Pal IX
#
#
S 0° 03’36”
South Chinese Sea
Legend:
S 0°02’2 4”
#
Sungai Itik
Pontianak City
Sungai Kupah
S 0°04’48”
Sungai Belidak
S 0°04’4 8”
S 0°03’36”
S 0°02’24”
Sungai Rengas
Kalimas #
#
Punggur Kecil
S 0° 06’36”
P.Tempurung
S0 ° 06’36”
#
#
Tanjung Saleh
P. Sepuk Perupuk
S 0°07’4 8”
S 0°07’4 8”
S 0° 05’24”
S0 ° 05’24”
P. Minyak
#
S 0°10’1 2”
Punggur Besar
Rasau Jaya Sub District
#
Teluk Pakadai Sub District
E 1 0 9 °08’24”
E 109°09’3 6”
W
E 109° 10’48”
E 109°12’
E 109 ° 11’12”
E 109°12’2 4”
E 109 ° 13’36”
E
S
S 0°11’24”
S 0°12’36”
S 0°12’36”
S 0° 11’24”
Sepuk Laut
E 109°07’12”
N
S 0°09’
#
#
P. Kurnia
S 0°10’1 2”
S 0°09’
P. Nyamuk
Sub district line.shp
Village.shp
Riv er.shp
Road. shp
Mangrove conserv ation area.shp
Teluk pakedai sub district. shp
Sepuk laut. shp
Punggur bes ar.shp
Tanjung saleh.shp
Rasau jaya sub district.shp
Siant an sub district.shp
Pal ix.shp
Kalimas.shp
Punggur kecil.shp
Sungai kupah.shp
Pont ianak city.shp
Sungai belidak.shp
Jeruju.shp
Sungai kakap.shp
Sungai itik.shp
Sungai rengas.shp
Sungai kakap sub district.shp
Sout h chinese sea.s hp
1 : 70,000
0
1
2
3
4 Km
Source: Resort Policemen of Sungai Kakap
Forestry Office of West Kalimantan
E 1 0 9 °14’4 8”
Figure 3 A map of Sungai Kakap Sub District, Pontianak Regency, West Kalimantan
The physical characteristics in the estuary of Sungai Kakap recorded during the
sampling are:
-
The maximum tidal range was 0.3 –1.9 m (neap tide 0.82 m on 29 April 2006 and
spring tide 1.60 m on 3 June 2006). The variation in high tide was ranged from 1.4 to
1.9 m, and in low tide was ranged from 0.3 to 0.6 m.
-
Water and air temperature were 24 to 27 °C and 25 to 28 °C respectively.
-
Salinity was 4 to 6 ‰. The low salinity levels reflected the large input of fresh water
from three rivers, namely Kakap River, Pungur Kecil River and Pungur Besar River.
-
Rainfall varied from 0.4 to 41.8 ml.
-
Water clarity and pH were 18 - 21 cm and 6.8 -7.1 respectively.
-
Water depth varied from 42 to 165 cm during low tide.
-
Dissolved oxygen slightly fluctuated from 2.04 to 2.54 mg/l.
12
-
Soil characters included grumosol of the soil type, yellow red of the soil color, and soil
texture with a range from 11.4% to 18.40% of sand, 33.40% to 56.20% of silt, and
32.40% to 49.20 of clay
(Detailed in Appendix 2).
Data Collections
The data collections had been divided into three places (each places has two stations)
(Figure 4), namely; northern part of the east of estuary (Station I and II), southern part of
the east of the estuary of Sungai Kakap(Station III and IV), and the west of estuary (Station
V and VI), where they had some different conditions caused by natural factors, such as;
river run of and mangrove species (Station I and II were dominated by “Nipah” (local
name), Station III and IV were dominated by “Berembang” (local name), and Station V
and VI were dominated by Berembang and Nipah.
E109°09’36’’
E109°10’12’’
E109°10’48’’
SAMPLING SITES
IN THE ESTUARY OF
SUNGAI KAKAP
E109°11’24’’
Station I
P. Panjang
Siantan Sub District
Kapuas River
SouthChinese Sea
Set Net 1
Jer uju Besar
#
#
Sungai Rengas
Legend:
i
Pontianak City
#
#
Station II
Set Net 6
#
#
Set Nets
Mangrove
#
P. Nyamuk
#
#
P. Ku rnia
Station III
S 0°04’12’’
l
River
Tanjun g Saleh
P. Sepuk Peru
Set Net 2
Station VI
Punggur Kecil
S 0°03’36’’
Sung
ai Kakap
#
Land
Punggur Besar
#
Sepuk L au t
Set Net 3
Teluk Pakadai Sub District
S 0°04’12’’
S 0°03’36’’
Sungai tIik#
Estuary
Mangrove Plots
N
S 0°04’48’’
S 0°04’48’’
Set Net 5
Station IV
Set Net 4
W
E
S
100
200
300 400 m
Station V
E109°09’36’’
E109°10’12’’
E109°10’48’’
E109°11’24’’
Source: Resort Policemen of Sungai Kakap
Forestry Office of West Kalimantan
Figure 4 Sampling sites for mangroves and shrimp catches in the set nets in the estuary of
Sungai Kakap.
Mangroves
To identify the characteristics and conditions of mangrove plants, “Transect Line
Plots” sampling method (English et al., 1994) was applied. Since the mangrove forest was
a narrow (10-100 m), the number of permanent plots had been set up horizontally within
13
the fringe along the coast (Figure 4). The kinds of mangrove data, equipments and general
procedures can be seen in Table 1.
Table 1 The kinds of mangrove data, procedures, and equipments that were conducted
during sampling in the estuary of Sungai Kakap, 2006
Data
Procedures
Mangrove
To establish permanent plots horizontally
characteristics (representative the general area), three replicate plots
of equal size (10 m x 10 m) for each station, and
mark the corner of the plots with stakes.
Identify and record the species of the tree (larger
than 4 cm in girth), sapling (girth less than 4 cm and
height greater than 1 m), and seedling (height less
than 1 m). Measure the girth of the tree stem was
taken at shoulder height (± 1.3 m above the ground).
Mangrove
Identify and record the suffered impacts caused by
conditions
anthropogenic activities along the coast
Equipments
GPS, tapes, stakes,
ropes
Preprinted data sheets
GPS, tapes, ropes,
preprinted data sheets
Shrimps
To examine the characteristics and productions of shrimps, shrimp catch data had
been collected from six fishermen’s set nets (two sample points for each station) located
along the coastal line parallel with mangrove sampling Stations. “Ambai” (set net) consist
of loose netting attached between a V-shaped frame made from bamboos stakes or Nypa
fruticans leaves.
It caught specially shrimps when it was low tide. A figure in the
Appendix 3 describes a set net fixed to sample shrimps in the estuary of Sungai Kakap.
The kinds of shrimp data, equipments and general procedures can be seen in Table 2.
Table 2 The kind s of shrimp data, equipments and general procedures that were taken
during sampling in the estuary of Sungai Kakap, 2006
Data
Procedures
Shrimp
To determine the position of the station located front
characteristics of mangrove sampling plots about 100 m distances
(six stations)
To catch shrimps using fishermen’s set nets that had
been determined as sample (eight replicates
undertaken every week for two months, each
replicate done in 15 minutes (06.00 – 08.00 a.m)
during the study).
The caught shrimps were observed the species
groups and calculated the numbers based on carapace
length. Survey had been concentrated on shrimp
specimen’s = 1 cm carapace length because of
taxonomic problems with smaller specimens.
Equipments
GPS
Labeled plastic bag
Ruler, yarn,
preprinted data
sheets.
14
Data Analyses
To analyze the mangrove plant healthiness including species density, species
frequency, species basal area (coverage) and species important value of mangrove were
analyzed with formulas as follows (English et al., 1994):
Density (D):
The density is a number of mangrove plants per unit area.
Di =
ni
.......................................................................................................................
A
Where: n i
(1)
= number of individuals of species i
A
= area of the plot (m²)
Relative Density (RD):
The relative density is comparative between number of plants of a mangrove species i and
the total number of mangrove plants.
RDi =
ni
∑n
×100 ..........................................................................................................
Where: n i
∑n
(2)
= number of individuals of species i
= total of number individuals (all species)
Frequency (F):
The frequency is probability to be found species i in sampling plot.
Fi =
Pi
∑P
....................................................................................................................
Where: Pi
∑P
(3)
= number of sampling where it is found species i
= total number of sampling
Relative Frequency (RF):
The relative frequency is comparative between frequenc y species i and the total frequency.
RFi =
Fi
×100 .........................................................................................................
∑F
Where: Fi
∑F
= frequency of species i
= total frequency of all species
(4)
15
Coverage (C):
Calculate the basal area (BA) for the stand in m² per hectare (ha). BA for each tree is the
cross-sectional area at breast height
BA =
πDBH 2
cm 2 .....................................................................................................
4
(
)
(5)
Where: DBH = trunk diameter of species i
Converting cm² to m², and ground area from m² to hectares
C=
∑ BA ⋅ m
A
Where:
2
ha −1 .......................................................................................................
∑ BA =
A
(6)
total BA of species i
= area of the plot (m²)
Relative Coverage (RC):
The relative coverage is comparative between basal area species i and the total basal area
all species.
RC i =
Ci
× 100 ..........................................................................................................
∑C
Where: Ci
∑C
(7)
= coverage species i
= total coverage all species
Important Value:
The important value of mangrove species (IVi) is sum of relative density (RDi), relative
frequency (RFi), and relative coverage (RCi) (Curtis, 1969 in English at al., 1994)
IVi = RDi + RFi + RC i ..................................................................................................
(8)
The important value of mangrove species is from 0 to 300. These values show a
explanation about the influence or the role of a mangrove species in the mangrove
communities.
Mangrove plant conditions were observed by index of human pressure (English et
al., 1994) computing their suffered impacts caused by anthropogenic activities in sites. To
describe the types of impact were computed with calculation of some codes value (each
code equal to one), namely; BU (Bunding or dyking), CO (Infrastucture, including jetties,
fish landing sites, construction sites or other coastal developments), ER (Erosion), IC
(Illegal cutting), MI (Mining activities), MU (Multiple impact), OT (Others), PP (Prawn or
fish pond), SC (Shell collecting), and SS (Severe storm). The sum of code values showed
the type of impact as follows: zero for no impact, one for slight impact, two for moderate
16
impact, three for rather high impact, four for high impact, and five for severe impact
(English et al., 1994)
The species of shrimp samples was observed by direct visual and then correlated
with literatures about taxonomic of shrimps (Dore and Frimodt, 1987; Centre of Research
and Fisheries Development, 1992); to handle the taxonomic problems, laboratory analysis
was conducted.
The distribution of a sample mean analysis was done to know the distribution of the
numbers of shrimps (based on both total number and carapace length’s number). The
normal distribution has its own standard deviation, that is, a standard deviation of sample
means (the standard error of the mean). The used formula was (Fowler and Cohen, 1990):
x ± S .E. ....................................................................................................................
(9)
Where:
x = a sample mean
SE =
STDEV
= Standard Error of the mean (standard deviation of a sample mean).
n
To be sure that a population mean lies between indicated limits was needed confidence
limits (intervals), 95% or 99% limits was generally used.
These were obtained by
multiplying the standard error by the appropriate score (t-score or z-score). The formula
was as follows:
x ± (t ( df , 95%) × S .E.) (a small sample) .......................................................................
(10)
x ± ( z ( df , 95%) × S .E.) or x ± 1.96SE (a large sample, more than 30 samples) ...........
(11)
Relationship between mangrove plant conditions and shrimp catches was done by a
simple regression analysis (Fowler
MANGROVE CONDITIONS IN THE ESTUARY
OF SUNGAI KAKAP, WEST KALIMANTAN
MACHMUD
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2006
THESIS STATEMENT AND INFORMATION SOURCES
Hereby I declare that thesis of Shrimps Caught by Set Net in Different Mangrove
Conditions in the Estuary of Sungai Kakap, West Kalimantan is my own casing, and that
no part of whole thesis has been printed or published in other universities yet. The
information sources cited from other authors were mentioned in the text and in the
references.
Bogor, September 2006
Machmud
NRP. C251040334
ABSTRACT
MACHMUD. Shrimps Caught by Set Net in Different Mangrove Conditions in the
Estuary of Sungai Kakap, West Kalimantan. Under supervision of UNGGUL AKTANI,
AGUSTINUS M. SAMOSIR, and ARIO DAMAR.
Mangrove ecosystem provides many benefits to local people both ecologically and
economically. Unfortunately, the mangrove forest has been degraded, due to the
increasing pressures of anthropogenic activities. Consequently, it would diminish most of
the life supported by mangrove, and threaten the security of local people livelihood. This
research was carried out to study the influence of mangrove plant conditions on shrimp
catches in set nets and how this contribute to local management plan. The method applied
for mangrove was transect line, and shrimps were collected with set net, and then they
were related each other to analyze the influences. This study showed that links between
mangrove plant conditions (area, density and coverage) and shrimp catch total and
carapace length give positive regression. Significant positive correlations are shown by the
relationship between percentage of mangrove area and number of Udang Ambai
(Metapenaeus lysianassa) with 1.0-1.5 cm carapace length with a simple linear regression
equation Y=23.5+0.3X (R²=0.62). The communities depend on mangroves and lives
supported by them, though the people were not found very aware about ecology, functions,
and threats of these resources. Therefore, the community involvement on the management
of mangrove ecosystem and shrimp catch is required. Zoning through the participation of
community is regarded as a major tool to achieve the goal of sustainable use of coastal
resources.
ABSTRAK
MACHMUD. Udang yang Ditangkap dengan Set Net (Ambai) pada Kondisi Mangrove
yang Berbeda di Estuari Sungai Kakap, Kalimantan Barat. Dibimbing oleh UNGGUL
AKTANI, AGUS TINUS M. SAMOSIR, dan ARIO DAMAR.
Ekosistem mangrove memiliki manfaat baik secara ekologi maupun ekonomi bagi
kehidupan masyarakat lokal. Namun dengan meningkatnya aktivitas manusia, hutan
mangrove mengalami degradasi yang akan menyebabkan menurunnya berbagai kehidupan
yang ditopang oleh keberadaan ekosistem tersebut, dan akan mengancam pada mata
pencaharian masyarakat lokal. Tujuan penelitian ini adalah untuk mengkaji pengaruh
kondisi tanaman mangrove pada penangkapan udang di dalam set net dan kontribusinya
terhadap perencanaan pengelolaaannya. Metode yang digunakan untuk mangrove adalah
transek garis, dan udang ditangkap menggunakan set net (ambai), dan kemudian
dihubungkan satu sama lain untuk menganalsis pengaruhnya. Hasil studi ini menunjukkan
bahwa hubungan kondisi tanaman mangrove (luas, kerapatan dan penutupan) dan
tangkapan udang total dan panjang carapace memberikan regresi yang positif. Persentase
luas mangrove terhadap jumlah Udang Ambai (Metapenaeus lysianassa) dengan panjang
carapace 1.0-1.5 cm memberikan pengaruh positive yang paling nyata dengan persamaan
regresi linear sederhana Y=23.5+0.3X (R²=0.62). Masyarakat dan beberapa kehidupan
tergantung pada mangrove, akan tetapi sebagian besar masyarakat belum begitu peduli
mengenai ekologi, fungsi dan ancaman terhadap sumberdaya tersebut. Untuk itu,
keterlibatab masyarakat pada pengelolaan ekosistem mangrove dan tangkapan udang
diperlukan. Zonasi melalui partisipasi masyarakat dipandang sebagai alat utama dalam
mencapai tujuan pemanfaatan sumberdaya pesisir secara berkelanjutan.
© Copyright property is owned by Machmud, 2006
All rights reserved
This thesis or parts thereof may not be reproduced in any form without written consent
from Bogor Agricultural University (IPB)
SHRIMPS CAUGHT BY SET NET IN DIFFERENT
MANGROVE CONDITIONS IN THE ESTUARY
OF SUNGAI KAKAP, WEST KALIMANTAN
MACHMUD
Thesis
as a partial fulfillment for Master Science Degree
in Marine and Coastal Resources Management
POST GRADUATE SCHOOL
BOGOR AGRICULTURAL UNIVERSITY
BOGOR
2006
Thesis Title
Name
Register Number
: Shrimps Caught by Set Net in Different Mangrove Conditions in the
Estuary of Sungai Kakap, West Kalimantan
: Machmud
: C251040334
Approved by Advisory Board
Dr. Unggul Aktani
Supervisor
Ir. Agustinus M. Samosir, M.Phil.
Co-supervisor
Dr. Ir. Ario Damar, M.Si.
Co-supervisor
Acknowledged by
Head of Study Program
Dean of Post Graduate School
Prof. Dr. Ir. Rokhmin Dahuri, M.S.
Dr. Ir. Khairil Anwar Notodiputro, M.S.
Date of examination: September 25th , 2006
Approved on:
PREFACE
Hereby I would like to give thankfulness God who has been giving its blessing to
me, so I could complete my thesis with title Shrimps Caught by Set Net in Different
Mangrove Conditions in the Estuary of Sungai Kakap, West Kalimantan. This thesis is as
a partial fulfillment for master science degree in Coastal and Marine Resources
Management Study Program.
I acknowledge the Marine and Coastal Resources Management Project at Marine
Affair and Fisheries for providing a scholarship of Sandwich Master Degree Program in
Bogor Agricultural University and Aarhus University-Denmark.
I also thank all persons for supporting to complete my thesis and to finish this study
program, namely:
1. Dr.Unggul Aktani, Ir. Agustinus M. Samosir, M.Phil and Dr. Ir. Ario Damar, M.Si as
my supervisors who gave tuition, advices, and guidance to complete from proposal
research to thesis.
2. Ir. Ki Agus Abdul Azis, M.Sc as a guess examiner and Dr. Ir. Mennofatria Boer, DEA
as a academic commission examiner for giving corrections and suggestions to improve
this thesis.
3. 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 for facilitating
the need of sandwich students during study.
4. Prof. Vibeke Simonsen and Prof. Mogens from Aarhus University Denmark who gave
suggestions and guidance in my minor thesis composing during the study in Aarhus
University, Denmark
5. Mr. Hardiono and staff from Fisheries Resort of Sungai Kakap for assisting during data
collection.
6. My colleagues in post graduate sandwich program; Zainal, Zaitul, Efrizal, Saptoyo,
Edo, Coki, Kusdiantoro, Neti, Normawati, Yesi, and Eiren for cooperation, friendship,
support, and advices during study.
7. All relations who could not be mentioned individually for their assistances and
cooperation.
Finally, I hope this thesis can give benefits to every one who need it.
.
Bogor, September 2006
Machmud
BIOGRAPHY OF AUTHOR
The author was born in Sumedang West Java on 08
January 1973 from the couple of H.Odjo, BA and Hj. Runasih,
and the youngest from four brothers.
In 1992, the author was graduated from Senior High
School (SMAN 2 Sumedang), and in 1997 the author was
graduated from Bogor Agricultural University (Institut Pertanian
Bogor) with Program Study of Agricultural Economic and
Resources, Socia l Economic Departement, Faculty of Agriculture.
In 2004, the author got schoolarship of Sandwich Master
Degree Program in Bogor Agricultural University and Aarhus
University-Denmark provided by Marine and Coastal Resources
Management Project (MCRMP) at Ministry of Marine Affair and Fisheries.
The author is a government employee, from 1998 to 2003 he had been working in
Ministry of Agriculture Jakarta, and from 2003 to day he have been working in Ministry of
Marine Affair and Fisheries Jakarta.
In 1996, the author has merried Nurul Quddusy, SP, and they have four children,
three sons (Sulthon Kamel, Tsamada Akhsani, Dhia Zaidan) and one daughter (Izatannisa
Nurma Ramadhani).
DEDICATION
TO
My mother, Hj. Runasih and my father, H. Odjo, BA who have mothered, educated, guided
and prayed.
And
TO
My wife, Nurul Quddusy, SP for her unfailing love, support and prayer, and to
our children, Sulthon Kamel, Izatannisa Nurma Ramadhani, Tsamada Akhsani, and Dhia
Zaidan who always give prayers and inspirations
TABLE OF CONTENTS
Pages
LIST OF TABLES .............................................................................................
xi
LIST OF FIGURES ............................................................................................
xii
LIST OF APPENDIXS ......................................................................................
xiv
INTRODUCTION ..............................................................................................
Background .................................................................................................
Hypothesis ........ .........................................................................................
Objectives ....................................................................................................
Advantages ..................................................................................................
1
1
2
2
2
LITERATURE REVIEWS ................................................................................
Mangrove ....................................................................................................
Shrimps .......................................................................................................
Relationship between Mangrove and Shrimps ...........................................
Management of Mangrove and Shrimp Catches ...……………………….
3
3
4
5
7
METHODS …………….....................................................................................
Research Framework …..............................................................................
Study Area ...................................................................................................
Data Collections ..........................................................................................
Mangrove ..............................................................................................
Shrimps .................................................................................................
Data Analyses ..............................................................................................
10
10
10
12
12
13
14
RESULT AND DISCUSSION ...........................................................................
Result ..........................................................................................................
Mangrove Conditions in the Estuary of Sungai Kakap……..................
Set Net Fishery in the Estuary of Sungai Kakap ...................................
Relationship between Mangrove and Shrimp Catches .........................
Discussion ...................................................................................................
Relationship between Mangrove and Shrimp in the Estuary of Sungai
Kakap ...................................................................................................
Management of Mangrove and Set Net Fishery....................................
18
18
18
19
21
27
CONCLUSION AND RECOMMENDATION .................................................
Conclusion ……………………........................................................
Recommendation ………………………………..…...........................
34
34
34
REFERENCE .....................................................................................................
35
APPENDIXES ...................................................................................................
39
27
30
LIST OF TABLES
Pages
1
The kinds of mangrove data, procedures, and equipments conducted
during sampling in the estuary of Sungai Kakap, 2006 ...............................
13
2
The kinds of shrimp data, procedures, and equipments conducted during
sampling in the estuary of Sungai Kakap, 2006 ...........................................
13
3
A design of regression with more than value of Y (shrimp catches) per
value of X (mangrove condition) with equal sample sizes ..........................
17
4
The present covering of mangrove area in the estuary of Sungai Kakap,
2006 ………………………………………………………………………..
18
5
Share of species to total shrimp abundance in six different stations (ST),
the estuary of Sungai Kakap, 2006................................................................
20
6
(
)
Distribution mean x ± SE of individual shrimp numbers per set net in six
different stations, the estuary of Sungai Kakap, 2006 ..................................
20
LIST OF FIGURES
Pages
1
The life cycle of penaeid shrimps (Masrtosudarmo and
Ranoemihardjo, 1979 in Eidman et al., 1983) ........................................
4
2
The research framework of the influence of mangrove conditions on
shrimp catches in set nets .......................................................................
10
3
A map of Sungai Kakap Sub District, Pontianak District, West
Kalimantan .............................................................................................
11
4
Schematic representation of sampling for mangroves and shrimp
catches in the set nets in the estuary of Sungai Kakap .........................
12
5
The density, coverage and important value of mangroves in six
different stations, the estuary of Sungai Kakap, 2006 ............................
19
6
(
)
Distribution mean x ± SE of M. lysianassa numbers with 1.0-1.5 cm
CL and 1.6-2.0 cm CL in six different stations, the estuary of Sungai
Kakap, 2006 …………………………………………………………...
21
The regression line and equation between percentage of mangrove
area (S. caseolaris and N. fruticans) and individual number of shrimp
catches …………………………………………………………………
22
The regression line and equation between percentage of mangrove
area (S. caseolaris and N. fruticans) and individual number of M.
lysianassa (1.0-1.5 cm CL) ……………………………………………
23
9
The regression line and equation between density of S. caseolaris and
individual number of shrimp catches ………………………………….
23
10
The regression line and equation between density of S. caseolaris and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
24
The regression line and equation between density of N.fruticans and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
24
12
The regression line and equation between coverage of S. caseolaris
and individual number of shrimp catches ……………………………..
25
13
The regression line and equation between coverage of S. caseolaris
and individual number of M. lysianassa (1.0-1.5 cm CL) …………….
25
14
The regression line and equation between coverage of N.fruticans and
individual number of M. lysianassa (1.0-1.5 cm CL) …………………
25
15
The regression line and equation between Important Value of S.
caseolaris and individual number of shrimps …………………………
26
7
8
11
16
17
18
The regression line and equation between Important Value of S.
caseolaris and individual number of M. lysianassa (1.0-1.5 cm CL) …
26
The regression line and equation between Important Value of
N.fruticans and individual number of M. lysianassa (1.0-1.5 cm CL) ..
26
Zonings for land use planning of a mangrove and shrimp catch
management in the estuary of Sungai Kakap, 2006 ...............................
31
LIST OF APPENDIXES
Pages
1
The Population of Sungai Kakap Subdistrict, 2003 ...............................
39
2
Physical parameters during sampling study in the estuary of Sungai
Kakap, 2006 ...........................................................................................
40
3
A set net fixed to sample shrimps in the estuary of Sungai Kakap .......
42
4
The features of “Berembang” (local name) in the estuary of Sungai
Kakap, 2006 ...........................................................................................
43
5
The features of “Udang Ambai”, “Udang Bajang”, “Udang Bulan”,
“Udang Gantung” and “Udang Galah” (local name) in the estuary of
Sungai Kakap, 2006 ...............................................................................
44
6
(
)
Confidence limit of shrimp catches distribution x ± (t (df , 95% ) × SE ) or
x ± (1.96 × SE ) for six different stations in the estuary of Sungai
Kakap, 2006 ...........................................................................................
47
INTRODUCTION
Background
Mangrove ecosystem provides many benefits to local people, both ecologically
and economically. Especially since this ecosystem gives important sources of food
for incredible diverse lives, such as fishes, crabs, shrimps, prawns, and mollusks
(Choong et al., 1990; Snedaker, 2005). Many penaeid species spawn in offshore, but
they use mangroves as refuge and feeding grounds during later stages (Christensen,
1983). For instance, mangrove ecosystem in the estuary of Sungai Kakap has certain
benefits on local fisheries specifically on shrimp catches.
Unfortunately, the mangrove ecosystem in the estuary of Sungai Kakap has
been degraded, due to the increasing pressures of anthropogenic activities, such as
agricultural activities, infrast ructure and residential. Study of Sudara and Singkran
(2005) showed that mangrove degradation caused a decreasing in fish abundance and
species richness. Furthermore, Melana et al. (2000) have shown that for every
hectare of mangrove cut down, a corresponding reduction in fish catch is estimated to
be 1.08 tons per year. Thus, the mangrove degradation in Sungai Kakap would
threaten the shrimp catches in those areas, and finally impact the security of local
people livelihood.
These causal-effect relatio nships should be understood by all stakeholders and
adjusted by local government in making especially policy on coastal resources
management. According to FAO (1995) the success of the resources management
will be achieved if all people involved in the management strive to maintain or
restore the coastal ecosystem.
Based on this phenomenon, the problems of study are formulated:
1.
What are the present conditions of mangrove in Sungai Kakap?
2.
Do the mangrove conditions influence on shrimp catches in set nets in Sungai
Kakap?
Consequently, this study will deal with the mangrove conditions and the ir
influences on shrimp catches in set nets in the estuary of Sungai Kakap.
2
Hypothesis
The shrimp catches in set nets are influenced by the mangrove conditions .
Objectives
The objectives of this study are:
1.
To identify the characteristics and conditions of mangrove .
2.
To identify the characteristics and distributions of shrimps in set nets.
3.
To study the influence of mangrove conditions on shrimp catches in set nets.
4.
To recommend a management alternative of mangrove and set net fishery.
Advantages
The advantages of this study are:
1.
Academically, the study results are expected to enrich the education literatures,
especially on the influence of mangrove conditions on shrimp catches in set
nets, and able to become a source for next researchers to further studies.
2.
Practically, the study results are expected to have benefit for local government
in term of mangrove ecosystem and set net fishery management.
LITERATURE REVIEWS
Mangrove in estuary provides important roles on commercial fisheries specifically
for shrimp productions. On the other hand, the anthropogenic activity pressures, such as
residential and agricultural activities, cause damage to this ecosystem and can destroy the
fisheries. From this knowledge the people should be understood about the relationship
between the mangrove healtheness and fisheries production (Simonsen, 2005). This
chapter will review mangrove, shrimps, and the management.
Mangrove
The mangrove terminology is used to define both a group of plants and a habitat
type in the coastal zone (Spalding, 2001). Eventhough mangroves consist of a group of
plants from many different genera and families; they exhibit numerous similarities in
appearance, physiology, reproduction and adaptation to habitat (Osborne, 2000).
Mangroves can survive in high salinity conditions, extreme tides, strong winds, high
temperatures, muddy, and anaerobic soils (Kathiresan and Bingham, 2001). These
adaptations to extreme conditions will determine the patterns of zonation in mangrove
communities (Spalding, 2001).
According to Zamani (2005), in general the mangrove zonations are divided into
three zones, namely: seaward zone, landward zone, and transition zone. The seaward zone
is an area which is found in proximity to shallow marine systems with sandy substrates and
often dominated by Avicennia and usually associated with Sonneratia. The landward zone
positioned behind the seaward zone is an area in the swamps dominated by Rhizophora,
Bruguiera and Xylocarpus (Chapman, 1976 in Choong et al., 1990). And the transition
zone is an area which located between mangrove forest and low land terrestrial forest,
usually dominated by Nypa fruticans and several species of palm trees (Bengen, 2004).
Nypa fruticans is also mainly found along the channel margins in the upper and middle
reaches of South East Asian estuaries where the salinity is between 1‰ and 10‰
(Robertson et al., 1991 in Blaber, 1997).
In West Kalimantan, the mangrove vegetations as pioneer community are
dominated by Api-Api (Avicennia marina), bogem (Sonneratia caseolaris) or perepat
(Sonneratia alba). In the river banks are usually grown by Bakau (Rhizophora mucronata
and Rhizophora apiculata). The landward sides are dominated by Berus (Bruguiera
gymnorhiza) and nyirih (Xylocarpus granatum) combined with Bakau (Rhizophora
4
mucronata and Rhizophora apiculata), while Nipah (Nypa fruticans) thrive in river bank
and estuary (The Strategic Planning (“Renstra”) of West Kalimantan Province, 2003).
Shrimps
The shrimps are classified as class of Crustacean, order of Decapoda, and suborder
Natantia that are divided into three infraorders, Penaeidae, Caridea, and Stenopodidea
(Dore and Frimodt, 1987).
The infraorder of Panaeidae that included in the family
Penaeidae of the super- family Penaeoidea is the important commercial shrimps of marine
tropical and sub-tropical waters (Dall, 1981) that consist of two genuses, namely: Penaeus
and Metapenaeus (Naamin, 1979 in Eidman et al., 1983) and that include 110 species
(Holthis, 1980 in Eidman et al., 1983). For example, the important commercial shrimp in
the estuary of Sungai Kakap is Metapenaeus lysianassa (“Udang Ambai” in local name),
with the total production 438.8 tons in 2005 (Fishery and Marine Resort of Sungai Kakap
Sub District, 2006).
In nature, the penaeid shrimps have three kinds of life cycle involving shrimps live
in offshore, shrimps live in inshore, and shrimps live in both the waters (Kirkegaard, 1975
in Eidman et al., 1983). However, almost all the shrimp larvae, both freshwater and
seawater, need estuary for growing into juvenile (Martosudarmo and Ranoemihardjo, 1979
in Eidman et al., 1983; D’Abramo and Brunson, 1996). The juvenile of marine shrimps
tend to move into deeper waters in accordance growth, and the sexual maturity is usually
achieved in waters of oceanic salinity (Dall, 1981). Figure 1 describes the life cycle of
shrimps from eggs to adult shrimp and their habitats.
Figure 1 The life cycle of penaeid shrimps (Masrtosudarmo and Ranoemihardjo, 1979 in
Eidman et al., 1983).
The environmental parameters that influence the distribution of penaeid shrimps are
salinity, tidal current, substrate types, food sources, and refuge place for living and
growing (Dall, 1981). Mair (1980) showed that the preference for low salinity inland
5
water might be an important factor in the immigration of postlarval penaeid shrimp from
the sea to their nursery grounds, such as estuaries, bays, and coastal lagoons. Pearse &
Gunter (1957) in Mair (1980) noted that it was generally the younger or smaller stages of
animals which inhabit low salinities, and although there are some exceptions, this certainly
applies to the Penaeidae.
Chong et al. (1990) explained that the coastal mangroves and mud flats were
important nursery areas for commercially important prawn species belonging to the genera
Penaeus and Metapenaeus. Furthermore, Ronnback et al. (2002) showed that Penaeus
indicus had a significant prefe rence for fringe mangroves over the adjacent sand flat and
Metapenaeus monoceros was significantly more abundant in the sand flat than in the
mangrove fringe, although this habitat preference was not evident for juvenile and subadult life stages.
Additionally, Eidman et al. (1983) showed that the abundances of
Metapenaeus ensis and M. lysianassa were influenced by spring and low tide, but the
abundances of Penaeus monodon and P. merguiensis in Banten Bay were not influenced
by tidal inundation.
Relationship between Mangrove and Shrimps
Mangrove has an important role as nursery grounds, feeding grounds, and
spawning grounds for waters biotes (fishes, shrimps, crabs, molluscs, etc.) (Christensen,
1983; Choong et al. 1990; Baran and Hambrey, 1999; Kathiresan and Bingham, 2001;
Spalding, 2001; Dahuri et al., 2001; Adeel and Pomeroy, 2002; Dahuri, 2003; Gunarto,
2004; Bengen, 2005). Two main reasons why mangrove is important as habitat for aquatic
species are: (1) it provides abundance food for an incredible dive rsity of life, namely:
coastal and offshore marine communities (Choong et al., 1990; Clough et al., 1994;
Snedaker, 2005), (2) mangrove roots above and below the ground provide many different
kinds of habitats, where aquatic animals can live and shelter from predation (Christensen,
1983; Clough et al., 1994; Melana et al., 2000; Ronnback et al., 2002).
Many species of penaeid juveniles migrate into mangrove waterways where they
live for some time before moving back to offshore waters as they approach reproductive
maturity (Clough et al., 1994). Genera Penaeus and Metapenaeus spawn at sea and after a
few weeks the postlarval shrimps settle in inshore and estuarine waters (Dall et al., 1990 in
Ronnback et al., 2002), which they use as nurseries during their critical early life stages.
The structure and function of these nursery grounds are usually characterized and
6
influenced by the presence of vegetation like mangrove forests and seagrass beds
(Ronnback et al., 2002)
Penaeid shrimp species in the Indo-Pacific are reported to have a preference for
mangrove as nursery ground includ ing Penaeus indicus (Chong et al., 1990), P.
merguiensis (Vance et al., 1990 in Ronnback et al., 2002), P. monodon (de Freitas, 1986 in
Ronnback et al., 2002), and P. penicil-latus (Chong et al., 1990). Other penaeid shrimp
species are, however, not confined to mangrove habitats as nursery grounds. For instance,
P. duorarum (Sheridan, 1992 in Ronnback et al., 2002), P. esculentus and P. semisulcatus
(Robertson & Duke, 1987 in Ro nnback et al., 2002) seem to have a preference for
submerged macrophytes like seagrass and algal beds. Metapenaeus monoceros (de Freitas,
1986 in Ronnback et al., 2002) and M. ensis (Robertson & Duke, 1987 in Ronnback et al.,
2002) are more widespread, occurring on seagrasses, mud flats, mangrove channels, etc.
Yanez-Arancibia et al. (1985) in Baran and Hambrey (1999) explained that a clear
positive correlation was shown between commercial finfish catches and the total area of
coastal vegetation - mostly mangroves in the Gulf of Mexico. Still in this area, Turner
(1977) in Baran and Hambrey (1999) found a positive correlation between shrimp catches
and the vegetated surface area of estuaries. In addition, Martosubroto and Naamin (1977)
in Baran and Hambrey (1999), in Indonesia, showed a positive correlation between annual
catch of prawns and area of mangrove. Paw and Chua (1989) in Baran and Hambrey
(1999), found in the Philippines a positive correlation between mangrove area and penaeid
shrimp catch. Staples et al. (1985) in Baran and Hambrey (1999), in Australia found a
positive correlation between the total length of mangrove lined rivers and the annual catch
of banana prawns, and Pauly and Ingles (1986) in Baran and Hambrey (1999) showed that
most of the variance of the MSY (Maximum Sustainable Yield) of penaeids could be
explained by a combination of area of mangrove habitats. Furthermore, Melana et al.
(2000) have shown that for every hectare of mangrove cut down, a corresponding
reduction in fish catch per year.
Ronnback et al. (1999) have described that the faunal distribution patterns in open
water habitat dominated by mangrove community (Avicennia or Rhizophora) provide new
and valuable information for the assessment of the ecological value of mangroves for
fisheries production. Shrimps and fish utilize large parts of the mangrove forest during
spring tide. The density of shrimp community in mangrove area is expressed through the
highest density in the habitat with the highest structural complexity, and a small-sized fish
community.
Further, Ronnback et al. (2002) investigated that Penaeus indicus had a
7
significant preference for fringe mangroves over the adjacent sand flat, and there was no
correlation between shrimp abundance and organic content of sediment.
Whereas,
Metapenaeus monoceros was significantly, more abundant in the sand flat than in the
mangrove fringe. In addition, Eidman et al. (1983) showed that the distribution pattern of
shrimps follow the distribution pattern of mangrove (Avicennia sp), where the shrimp
abundances were less to upstream parallel with the richness of Avicennia species which
was also less to landward.
Management of Mangrove and Shrimp Catches
Management of mangrove ecosystems is an effort that should be done to prevent a
decrease of mangrove areas, so that the roles of this ecosystem can be sustainable to fulfill
the needs of the present without compromising the ability of future generations to meet
theirs (UN, 1987). The fundamental objective of mangrove ecosystem management is to
promote conservation, and where necessary restoration or rehabilitation and sustainable
use of mangrove ecosystems and their associated habitats to benefit local to global
populations (Macintosh and Ashton, 2005).
Identificatio n of existing condition of mangrove that based on the location,
ecological characteristics and values could be used to determine the preservation,
conservation or sustainable utilization areas.
The pristine mangrove forest should be
preserved or declared as forest reserves, while mangrove areas near or adjacent to known
habitats important as fish, mollusk and crustacean nurseries and/or fishing grounds should
not be alienated or released for development. Some mangrove areas in urban areas should
be conserved exclusively for sustainable utilization by the local people who should be
involved in any reforestation and maintenance efforts. Rehabilitating areas of destroyed
mangroves through natural regeneration, assisted if necessary by active intervention,
including restoration of the hydrological regime and/or planting mangroves. Mangroves on
small islands serve as a major ecological component of the island ecosystem and should in
no case be disturbed. Mangroves in estuarine areas should be protection zone areas of
mangroves preserved on the banks of the mouth of the river fronting the sea (Macintosh
and Ashton, 2005).
Fisheries that associated with mangrove conditions give importance food and
income for local communities. However, lack of enforcement of existing fishery
regulations, including lack of protection of mangrove nursery sites and habitat degradation
are among the major reasons for the widespread decline in mangrove fisheries. Full
8
attention should be taken to support the livelihoods of mangrove fishers, to promote
awareness of mangrove ecosystems, and to help local communities to adopt a sustainable
management of mangrove.
According to Centre of Research and Fisheries Development (1992) management
practice of shrimp resources should consider fisheries management strategic including size
control, allowable catch number, effort control, and selective fishing gear in order to get
the optimal and sustainable fisheries. A closing technique and fishing seasons are to
control the number and shrimp sizes. Allowable catch size can be carried out by mesh size
control so it can protect the young shrimps. Effort control is to prevent over fishing in
certain area through to create a new fishing ground in other places or to limit the number of
fishing effort wit h license restriction. While selective fishing gear is fishing gear, which
have been designed to exclude/reduce the capture of unwanted sizes and species of fish and
the incidental catch, and release these excluded fish from the fishing gear with a high
survival (FAO, 1995).
As a river buffer zone, mangrove areas in Sungai Kakap are managed by Forestry
Office (UU No 41 1999), while shrimp catches management is under Fishery Office,
especially for fishing licenses of all fishing gears operated and fee of fishery business.
Based on these regulations, the coordination between these institutions must be done to
ensure the application of management. According to FAO (1995) the success of this
management will be achieved if all people involved in this management strive to maintain
or restore the coastal ecosystem. Therefore, the sustainable ecosystem management can be
attained through community based management approaches that provide a sense of
belongings with full participation, cooperation and empowerment of the all involved
stakeholders
According to the Centre for Community- Based Resource Management (2005),
“Community- Based Resource Management (CBRM) is a development approach that
emphasizes the interconnectedness of humans and all other living beings and their natural
environment”. Therefore, the present people who live in an ecosystem have the most
important responsibility to control their activities in a way that promotes this renewal and
sustains resource abundance and environmental friendliness for future generations. In
addition, Klinger (2004) reports that an Integrated Coastal Zone Management (ICZM)
approach that has been proven successfully in the long term is a integration of whole
stakeholder participation to formulate socially acceptable solution to problems of
sustainable resource management in coastal zones. Further, Pomeroy (1995) explains that
9
the management will be better implemented and managed when the local communities (i.e.
fishermen) and other related stakeholders are more involved in the resources management
and the access rights are distributed more effectively and rightfully.
Community based management approaches require clear and well-organized
management policies from all the stakeholders. The policies should be developed with
cooperation of all groups that have an interest in coastal area, including the local
communities, local government (such as fisheries office, environmental office and forestry
office), center government (such as ministry of forestry, ministry of marine and fisheries),
NGO, and other interested organizations (Strategic Planning (“Renstra”) of West
Kalimantan Province, 2003). Adeel and Pomeroy (2002) explain that a management
policy to protect and conserve mangrove forests and to give a local livelihood security can
be valued by the worth and success of community based management approaches for
protection and conservation.
METHODS
Research Framework
The research framework of shrimps caught by set net in different mangrove
conditions in the estuary of Sungai Kakap is shown in Figure 2.
Figure 2 The research framework of shrimps caught by set net in different mangrove
conditions.
Study Area
Sungai Kakap is a sub district situated in the western part of Pontianak (22 km from
Pontianak City), West Kalimantan Province on the Borneo Island (0°03’15”N – 0°15’33” S
and 109° 4’ E - 109° 21’ E) (Figure 3). This study was performed in the estuary of Sungai
Kakap Sub District (0°03’00”S – 0°05’06” S and 109°09’36” E - 109°10’48” E (Figure 3).
The total area of site about 7.4 km², with 7 km long and around 1 km wide, and has 1-3 m
deep at the lower reaches during low tides. This estuary derived from several drainages
including Kakap River from the east, Pungur Kecil River and Pungur Besar River from the
south. The water front was surrounded by mangrove communities, which cover a further
area of 35.86 hectares. Landward, it was bounded by seven villages, namely: Tanjung
Saleh, Sungai Kakap, Sungai Belidak, Kalimas, Pungur Besar, Pungur Kecil and Sungai
Kupah (Figure 3), with a 2003 population reported to be 45,635 (51.5% of the total
11
population of Sungai Kakap Sub District) (Statistical Bureau of Pontianak District, 2003)
(Appendix 1).
E 109°07’1 2”
E 109 ° 08’24”
E 109°09’36”
E 109°10’48”
E 109°12’
E 109°11’12”
E 109°13’36”
E 109 ° 14’48”
SUNGAI KAKAP
SUB DISTRICT MAP
PONTIANAK REGENCY
WEST KALIMANTAN
Siantan Sub District
P. Panjang
0°
0°
E 109°12’24”
Jeruju Besar
S 0° 01’12”
S 0°01’12”
Kapuas River
South
Sea
West Chinese
Kalimantan
#
#
Sungai Kakap
Pal IX
#
#
S 0° 03’36”
South Chinese Sea
Legend:
S 0°02’2 4”
#
Sungai Itik
Pontianak City
Sungai Kupah
S 0°04’48”
Sungai Belidak
S 0°04’4 8”
S 0°03’36”
S 0°02’24”
Sungai Rengas
Kalimas #
#
Punggur Kecil
S 0° 06’36”
P.Tempurung
S0 ° 06’36”
#
#
Tanjung Saleh
P. Sepuk Perupuk
S 0°07’4 8”
S 0°07’4 8”
S 0° 05’24”
S0 ° 05’24”
P. Minyak
#
S 0°10’1 2”
Punggur Besar
Rasau Jaya Sub District
#
Teluk Pakadai Sub District
E 1 0 9 °08’24”
E 109°09’3 6”
W
E 109° 10’48”
E 109°12’
E 109 ° 11’12”
E 109°12’2 4”
E 109 ° 13’36”
E
S
S 0°11’24”
S 0°12’36”
S 0°12’36”
S 0° 11’24”
Sepuk Laut
E 109°07’12”
N
S 0°09’
#
#
P. Kurnia
S 0°10’1 2”
S 0°09’
P. Nyamuk
Sub district line.shp
Village.shp
Riv er.shp
Road. shp
Mangrove conserv ation area.shp
Teluk pakedai sub district. shp
Sepuk laut. shp
Punggur bes ar.shp
Tanjung saleh.shp
Rasau jaya sub district.shp
Siant an sub district.shp
Pal ix.shp
Kalimas.shp
Punggur kecil.shp
Sungai kupah.shp
Pont ianak city.shp
Sungai belidak.shp
Jeruju.shp
Sungai kakap.shp
Sungai itik.shp
Sungai rengas.shp
Sungai kakap sub district.shp
Sout h chinese sea.s hp
1 : 70,000
0
1
2
3
4 Km
Source: Resort Policemen of Sungai Kakap
Forestry Office of West Kalimantan
E 1 0 9 °14’4 8”
Figure 3 A map of Sungai Kakap Sub District, Pontianak Regency, West Kalimantan
The physical characteristics in the estuary of Sungai Kakap recorded during the
sampling are:
-
The maximum tidal range was 0.3 –1.9 m (neap tide 0.82 m on 29 April 2006 and
spring tide 1.60 m on 3 June 2006). The variation in high tide was ranged from 1.4 to
1.9 m, and in low tide was ranged from 0.3 to 0.6 m.
-
Water and air temperature were 24 to 27 °C and 25 to 28 °C respectively.
-
Salinity was 4 to 6 ‰. The low salinity levels reflected the large input of fresh water
from three rivers, namely Kakap River, Pungur Kecil River and Pungur Besar River.
-
Rainfall varied from 0.4 to 41.8 ml.
-
Water clarity and pH were 18 - 21 cm and 6.8 -7.1 respectively.
-
Water depth varied from 42 to 165 cm during low tide.
-
Dissolved oxygen slightly fluctuated from 2.04 to 2.54 mg/l.
12
-
Soil characters included grumosol of the soil type, yellow red of the soil color, and soil
texture with a range from 11.4% to 18.40% of sand, 33.40% to 56.20% of silt, and
32.40% to 49.20 of clay
(Detailed in Appendix 2).
Data Collections
The data collections had been divided into three places (each places has two stations)
(Figure 4), namely; northern part of the east of estuary (Station I and II), southern part of
the east of the estuary of Sungai Kakap(Station III and IV), and the west of estuary (Station
V and VI), where they had some different conditions caused by natural factors, such as;
river run of and mangrove species (Station I and II were dominated by “Nipah” (local
name), Station III and IV were dominated by “Berembang” (local name), and Station V
and VI were dominated by Berembang and Nipah.
E109°09’36’’
E109°10’12’’
E109°10’48’’
SAMPLING SITES
IN THE ESTUARY OF
SUNGAI KAKAP
E109°11’24’’
Station I
P. Panjang
Siantan Sub District
Kapuas River
SouthChinese Sea
Set Net 1
Jer uju Besar
#
#
Sungai Rengas
Legend:
i
Pontianak City
#
#
Station II
Set Net 6
#
#
Set Nets
Mangrove
#
P. Nyamuk
#
#
P. Ku rnia
Station III
S 0°04’12’’
l
River
Tanjun g Saleh
P. Sepuk Peru
Set Net 2
Station VI
Punggur Kecil
S 0°03’36’’
Sung
ai Kakap
#
Land
Punggur Besar
#
Sepuk L au t
Set Net 3
Teluk Pakadai Sub District
S 0°04’12’’
S 0°03’36’’
Sungai tIik#
Estuary
Mangrove Plots
N
S 0°04’48’’
S 0°04’48’’
Set Net 5
Station IV
Set Net 4
W
E
S
100
200
300 400 m
Station V
E109°09’36’’
E109°10’12’’
E109°10’48’’
E109°11’24’’
Source: Resort Policemen of Sungai Kakap
Forestry Office of West Kalimantan
Figure 4 Sampling sites for mangroves and shrimp catches in the set nets in the estuary of
Sungai Kakap.
Mangroves
To identify the characteristics and conditions of mangrove plants, “Transect Line
Plots” sampling method (English et al., 1994) was applied. Since the mangrove forest was
a narrow (10-100 m), the number of permanent plots had been set up horizontally within
13
the fringe along the coast (Figure 4). The kinds of mangrove data, equipments and general
procedures can be seen in Table 1.
Table 1 The kinds of mangrove data, procedures, and equipments that were conducted
during sampling in the estuary of Sungai Kakap, 2006
Data
Procedures
Mangrove
To establish permanent plots horizontally
characteristics (representative the general area), three replicate plots
of equal size (10 m x 10 m) for each station, and
mark the corner of the plots with stakes.
Identify and record the species of the tree (larger
than 4 cm in girth), sapling (girth less than 4 cm and
height greater than 1 m), and seedling (height less
than 1 m). Measure the girth of the tree stem was
taken at shoulder height (± 1.3 m above the ground).
Mangrove
Identify and record the suffered impacts caused by
conditions
anthropogenic activities along the coast
Equipments
GPS, tapes, stakes,
ropes
Preprinted data sheets
GPS, tapes, ropes,
preprinted data sheets
Shrimps
To examine the characteristics and productions of shrimps, shrimp catch data had
been collected from six fishermen’s set nets (two sample points for each station) located
along the coastal line parallel with mangrove sampling Stations. “Ambai” (set net) consist
of loose netting attached between a V-shaped frame made from bamboos stakes or Nypa
fruticans leaves.
It caught specially shrimps when it was low tide. A figure in the
Appendix 3 describes a set net fixed to sample shrimps in the estuary of Sungai Kakap.
The kinds of shrimp data, equipments and general procedures can be seen in Table 2.
Table 2 The kind s of shrimp data, equipments and general procedures that were taken
during sampling in the estuary of Sungai Kakap, 2006
Data
Procedures
Shrimp
To determine the position of the station located front
characteristics of mangrove sampling plots about 100 m distances
(six stations)
To catch shrimps using fishermen’s set nets that had
been determined as sample (eight replicates
undertaken every week for two months, each
replicate done in 15 minutes (06.00 – 08.00 a.m)
during the study).
The caught shrimps were observed the species
groups and calculated the numbers based on carapace
length. Survey had been concentrated on shrimp
specimen’s = 1 cm carapace length because of
taxonomic problems with smaller specimens.
Equipments
GPS
Labeled plastic bag
Ruler, yarn,
preprinted data
sheets.
14
Data Analyses
To analyze the mangrove plant healthiness including species density, species
frequency, species basal area (coverage) and species important value of mangrove were
analyzed with formulas as follows (English et al., 1994):
Density (D):
The density is a number of mangrove plants per unit area.
Di =
ni
.......................................................................................................................
A
Where: n i
(1)
= number of individuals of species i
A
= area of the plot (m²)
Relative Density (RD):
The relative density is comparative between number of plants of a mangrove species i and
the total number of mangrove plants.
RDi =
ni
∑n
×100 ..........................................................................................................
Where: n i
∑n
(2)
= number of individuals of species i
= total of number individuals (all species)
Frequency (F):
The frequency is probability to be found species i in sampling plot.
Fi =
Pi
∑P
....................................................................................................................
Where: Pi
∑P
(3)
= number of sampling where it is found species i
= total number of sampling
Relative Frequency (RF):
The relative frequency is comparative between frequenc y species i and the total frequency.
RFi =
Fi
×100 .........................................................................................................
∑F
Where: Fi
∑F
= frequency of species i
= total frequency of all species
(4)
15
Coverage (C):
Calculate the basal area (BA) for the stand in m² per hectare (ha). BA for each tree is the
cross-sectional area at breast height
BA =
πDBH 2
cm 2 .....................................................................................................
4
(
)
(5)
Where: DBH = trunk diameter of species i
Converting cm² to m², and ground area from m² to hectares
C=
∑ BA ⋅ m
A
Where:
2
ha −1 .......................................................................................................
∑ BA =
A
(6)
total BA of species i
= area of the plot (m²)
Relative Coverage (RC):
The relative coverage is comparative between basal area species i and the total basal area
all species.
RC i =
Ci
× 100 ..........................................................................................................
∑C
Where: Ci
∑C
(7)
= coverage species i
= total coverage all species
Important Value:
The important value of mangrove species (IVi) is sum of relative density (RDi), relative
frequency (RFi), and relative coverage (RCi) (Curtis, 1969 in English at al., 1994)
IVi = RDi + RFi + RC i ..................................................................................................
(8)
The important value of mangrove species is from 0 to 300. These values show a
explanation about the influence or the role of a mangrove species in the mangrove
communities.
Mangrove plant conditions were observed by index of human pressure (English et
al., 1994) computing their suffered impacts caused by anthropogenic activities in sites. To
describe the types of impact were computed with calculation of some codes value (each
code equal to one), namely; BU (Bunding or dyking), CO (Infrastucture, including jetties,
fish landing sites, construction sites or other coastal developments), ER (Erosion), IC
(Illegal cutting), MI (Mining activities), MU (Multiple impact), OT (Others), PP (Prawn or
fish pond), SC (Shell collecting), and SS (Severe storm). The sum of code values showed
the type of impact as follows: zero for no impact, one for slight impact, two for moderate
16
impact, three for rather high impact, four for high impact, and five for severe impact
(English et al., 1994)
The species of shrimp samples was observed by direct visual and then correlated
with literatures about taxonomic of shrimps (Dore and Frimodt, 1987; Centre of Research
and Fisheries Development, 1992); to handle the taxonomic problems, laboratory analysis
was conducted.
The distribution of a sample mean analysis was done to know the distribution of the
numbers of shrimps (based on both total number and carapace length’s number). The
normal distribution has its own standard deviation, that is, a standard deviation of sample
means (the standard error of the mean). The used formula was (Fowler and Cohen, 1990):
x ± S .E. ....................................................................................................................
(9)
Where:
x = a sample mean
SE =
STDEV
= Standard Error of the mean (standard deviation of a sample mean).
n
To be sure that a population mean lies between indicated limits was needed confidence
limits (intervals), 95% or 99% limits was generally used.
These were obtained by
multiplying the standard error by the appropriate score (t-score or z-score). The formula
was as follows:
x ± (t ( df , 95%) × S .E.) (a small sample) .......................................................................
(10)
x ± ( z ( df , 95%) × S .E.) or x ± 1.96SE (a large sample, more than 30 samples) ...........
(11)
Relationship between mangrove plant conditions and shrimp catches was done by a
simple regression analysis (Fowler