scholarly journals Stock Assessment of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) in Stock Enhancement Sites of Danajon Bank, Central Philippines

2021 ◽  
pp. 210-227
Author(s):  
Bruna Abrenica ◽  
Mary Jane Fajardo ◽  
Johnson Paran ◽  
Mario Ruinata ◽  
Marinelle Espino ◽  
...  
Keyword(s):  
Stock Assessment ◽  
Stock Enhancement ◽  
Population Characteristics ◽  
Assessment Tools ◽  
Swimming Crab ◽  
Catch Per Unit Effort ◽  
Portunus Pelagicus ◽  
Exploitation Rate ◽  
Spawning Potential Ratio ◽  
The Impact

The stock status of Blue Swimming Crab (BSC), Portunus pelagicus, locally known as lambay, in Danajon Bank was assessed from June 2019 to September 2020 to monitor the impact of the BSC stock enhancement initiative by the Philippine Association of Crab Processors, Inc. (PACPI) in collaboration with BFAR 7. The stock was assessed based on the indicators, namely, catch per unit effort (CPUE), exploitation rate (E), average size, length at first maturity (Lm), and Spawning Potential Ratio (SPR). Data analysis was done using FAO-ICLARM Stock Assessment Tools (FiSAT) II software and the Barefoot Ecologist’s Toolbox for the Length-based Spawning Potential Ratio (SPR). Results show that BSC dominated the monitored landings accounting for 66% of the overall catch harvested mainly by crab pot and crab net. Higher CPUEs were obtained in the months of July, June, May and August with annual mean observed to be higher than the previous assessment conducted by ECOFISH in Danajon Bank particularly for crab pot. Population characteristics revealed that male crab grew slightly faster having higher asymptotic length (L∞ =21.65cm Carapace Width or CW) and growth constant (K=1.3yr-1) than female (L∞ =21.40cm CW, K=1.28yr-1). Sex ratio of male to female was at 1:1.28 indicating plenty of female crabs were captured than male. Gravid crabs were abundant in May, December, April and October. Recruitment pattern showed two pulses with primary peak occurred in April and May and secondary pulse happened in August and September. Encouraging performance indicator noted from this assessment was on the bigger probability of capture sizes and mean length of commonly caught BSC falling above the recommended catchable size of 10.2 cm CW pursuant to DA-DILG JAO No. 1 s. 2014. Maturity size (Lm) was estimated at 10.54 cm CW, though smaller than the previous reported Lm values in Danajon but still within the threshold. The estimated SPR was 26%, higher than 20% limit reference point but slightly lower than 27% recorded in the assessment done by ECOFISH Project in 2014 to 2015. The present SPR though lower than 30% precautionary threshold however higher than 21% generated in Visayan Sea Region 7 for the same period. The higher SPR in Danajon Bank compared to Visayan Sea maybe credited to the effect of stock enhancement activity implemented in the area, though observation is not yet conclusive. On the other hand, unfavorable indicators were seen on high exploitation rate (E), high exploitation at yield per recruit some of which already breached the optimum level, consequently subjecting Danajon Bank to high fishing pressure. It is recommended to continue the BSC stock enhancement program of PACPI and BFAR 7 taking consideration some strategies for improvement specified in the recommendations.

scholarly journals Stock Status of Blue Swimming Crab (Portunus pelagicus Linnaeus, 1758) in Tiworo Strait Waters, Southeast Sulawesi, Indonesia

2020 ◽  
Vol 25 (2) ◽  
pp. 85-90
Author(s):  
Yustika Permatahati Intan Permatahati ◽  
Nila Nikmatia Bugis ◽  
La Sara ◽  
Tezza Fauzan Hasuba Hasuba
Keyword(s):  
Carapace Width ◽  
Growth Patterns ◽  
Fishing Ground ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female ◽  
Gonad Maturity ◽  
Stock Status ◽  
Spawning Potential Ratio ◽  
Very High

The blue swimming crab (BSC) fishery in Tiworo Strait has been heavily exploited since two decades ago when its worldwide demand and price was very high. Study on population aspects of this organism in this waters is limited. The aim of present study was to investigate growth patterns, population stock status, and size at first gonad maturity of Portunus pelagicus. One of the main fishing ground of BSC around Tiworo Strait waters is at Bangko and Gala Islands. Samples of BSC were taken monthly using gillnet and collapsible trap. Each sample taken was identified its sex, measured its carapace width, and weighed. Data collected from fishing ground of BSC were analyzed to find out growth patterns, population stock status using spawning potential ratio (SPR) method, and the first gonad maturity (CW50). The results of study showed that growth patterns of BSC male and female following isometric growth patterns (b=0) (P<0.05). It was found out that SPR of BSC from both fishing ground was 22.46% and 23.71%, respectively which indicates that population stock status of BSC in Tiworo strait waters is “moderate level” (SPR > 20%). The size at first gonad maturity (CW50) was attained at carapace width of 9.16 cm for male and 10.16 cm for female. Those imply that BSCs allowed to be caught should be >10 cm. 

scholarly journals PARAMETER POPULASI DAN TINGKAT PENGUSAHAAN RAJUNGAN (Portunus pelagicus) DI PERAIRAN ASAHAN, SELAT MALAKA

2017 ◽  
Vol 9 (2) ◽  
pp. 93
Author(s):  
Andina Ramadhani Putri Pane ◽  
Heri Widiyastuti ◽  
Ali Suman
Keyword(s):  
Mortality Rate ◽  
Carapace Width ◽  
Total Mortality ◽  
Optimum Level ◽  
Market Demand ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Monthly Data ◽  
Management Measures ◽  
Exploitation Rate

Tingginya permintaan pasar terhadap rajungan mengakibatkan aktivitas penangkapannya berlangsung secara intensif. Selat Malaka merupakan salah satu daerah penangkapan rajungan yang penting di Indonesia. Tujuan penelitian ini adalah untuk mengestimasi parameter populasi dan tingkat eksploitasi rajungan (Portunus pelagicus) di perairan Asahan dan sekitarnya. Pengumpulan data bulanan dilakukan pada bulan Juni 2015 sampai dengan Nopember 2016. Hasil penelitian menunjukkan bahwa musim penangkapan berlangsung sepanjang tahun dengan puncak pada bulan Juli dan Oktober, puncak pemijahan terjadi pada bulan Januari dan Agustus. Ukuran lebar karapas pertama kali tertangkap dengan gillnet (Lc) dan ukuran pertama kali matang gonad (Lm) masing-masing sebesar 109,6 mm dan 104,1 mm. Laju pertumbuhan (K) sebesar 1,38/tahun dan lebar karapas asimtotik (L) sebesar 183,10 mm. Laju kematian total (Z) rajungan sebagai 4,31 per tahun, laju kematian karena penangkapan (F) dan laju kematian alami (M) masing-masing 2,96 per tahun dan 1,35 per tahun; laju eksploitasi (E) diestimasi sebesar 0,69. Tingkat pemanfaatan rajungan di perairan Asahan diduga telah melewati optimal, sehingga perlu dilakukan pengelolaan melalui pengurangan jumlah unit gillnet rajungan sebanyak 38% dari kondisi saat ini. Blue swimming crab faced intensive fishing pressure due to the high market demand. The Malacca Strait is one of important fishing area for blue swimming crab. The research aims to estimate the population parameters and exploitation rate of blue swimming crab (Portunus pelagicus) in the Asahan and adjacent waters. A monthly data were collected from June 2015 to November 2016 that caught by Gillnet. The results showed that the fishing season takes place throughout the year with peaks in July and October, meanwhile peak of spawning season in January and August. The carapace width at first capture (Lc) and first mature (Lm) were 109.6 mm and 104.1 mm, respectively. The growth rate (K) was 1.38 / year and the asymptotic length (L) was 183.10 mm. Total mortality rate (Z) was 4.31 per year, fishing mortality rate (F) and natural mortality rate (M) were 2.96 per year and 1.35 per year respectively; Exploitation rate (E) was estimated at 0.69. It means that the exploitation rate of swimming crab in the Asahan waters found exceed the optimum level, therefore the management measures needs to reduce effort (unit) of gillnet by a 38% of actual level. 

scholarly journals STRUKTUR UKURAN DAN BIOLOGI POPULASI RAJUNGAN (Portunus pelagicus Linnaeus, 1758) DI PERAIRAN KEPULAUAN ARU

2018 ◽  
Vol 1 (1) ◽  
pp. 51
Author(s):  
Duranta Diandria Kembaren ◽  
Adi Surahman
Keyword(s):  
Population Biology ◽  
Size Structure ◽  
Carapace Width ◽  
Total Mortality ◽  
Swimming Crab ◽  
Fishing Mortality ◽  
Portunus Pelagicus ◽  
Precautionary Approach ◽  
Exploitation Rate ◽  
Average Size

Penelitian struktur ukuran dan biologi populasi rajungan di perairan Kepulauan Aru telah dilakukan pada Januari-April, Juni dan Agustus-November 2016. Penelitian ini bertujuan untuk mengidentifikasi struktur ukuran dan biologi populasi yang meliputi pertumbuhan, laju kematian, dan tingkat eksploitasi rajungan. Pemahaman struktur ukuran dan biologi populasi dapat dijadikan dasar masukan untuk pengelolaan perikanan. Rata-rata ukuran lebar karapas rajungan yang tertangkap sebesar 136 mm untuk jantan dan 141 mm untuk betina. Rajungan yang tertangkap pada Januari dan Juni memiliki rata-rata ukuran yang lebih besar. Rata-rata rajungan yang tertangkap sudah melawati ukuran matang gonad (Lc = 133,4 mm > Lm = 119,9 mm). Puncak musim pemijahan terjadi pada Februari-Maret dan Agustus-September. Lebar karapas asimtosis (CW) sebesar 185 mm dengan laju pertumbuhan (K) 1,15 tahun-1 serta laju kematian total (Z) 4,94 tahun-1, laju kematian alamiah (M) 1,20 tahun-1 serta laju kematian akibat penangkapan (F) 3,74 tahun-1. Laju eksploitasi sudah berada pada kondisi lebih tangkap (E=0,76). Hasil kajian menyarankan bahwa pengelolaan perikanan rajungan perlu dilakukan secara hati-hati agar sumberdaya ini dapat lestari. Salah satu upaya yang dapat di tempuh adalah dengan menerapkan sistem penutupan musim penangkapan rajungan pada saat terjadinya puncak musim pemijahan yaitu pada Februari-Maret dan Agustus-September. Dengan demikian diharapkan proses regenerasi dan rekrutmen rajungan selalu dapat mendukung ketersedian stok sumberdaya rajungan di perairan Kepulauan Aru ini. Study on the size structure and population biology of blue swimming crab in the waters of Kepualuan Aru was conducted in January to April, June and August to November 2016. The aim of this study was to identify the size structure and population biology i.e. growth, mortality, and exploitation rate of blue swimming crab. Understanding on the size structure and population biology can be used as basic information for managing blue swimming crab fisheries.  Average size of carapace width of blue swimming crab was 136 mm for male and 141 mm for female. Catch on January and June  was bigger size than others months. Length at first capture was higher than length at maturity (Lc = 133,4 mm > Lm = 119,9 mm). Spawning peak season occurs in  February-March and August-September. Asymptotic carapace width (CW) of blue swimming crab was 185 mm with the growth rate (K) was 1,20 year-1, total mortality (Z) was 4,94 year-1, natural mortality (M) was 1,20 year-1, and fishing mortality (F) was 3,74 year-1. Exploitation rate was exceed the sustainability limit (E = 0,76). Thus, it is needed to manage the blue swimming crab fishery with precautionary approach. Based on this study, we suggest to apply the fishing closure system at the peak of spawning season. Thus, the regeneration process and recruitment will support the availability of blue swimming crabs resource in Kepualuan Aru waters.

scholarly journals PENENTUAN STATUS STOK SUMBERDAYA RAJUNGAN (Portunus pelagicus Linnaeus, 1758) DENGAN METODE SPAWNING POTENTIAL RATIO DI PERAIRAN SEKITAR BELITUNG

2015 ◽  
Vol 21 (2) ◽  
pp. 63
Author(s):  
Tri Ernawati ◽  
Duranta D Kembaren ◽  
Karsono Wagiyo
Keyword(s):  
Carapace Width ◽  
Population Decline ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Average Value ◽  
Stock Status ◽  
The Status ◽  
Spawning Potential Ratio ◽  
Individual Size ◽  
Stock Recovery

<em><em></em></em><p>Sumber daya rajungan (Portunus pelagicus Linnaeus, 1758) di perairan sekitar Belitung dieksploitasi terus menerus dilakukan sebagai sumber mata pencaharian. Pemanfaatan intensif sumber daya rajungan dapat menurunkan ketersediaan stok rajungan di perairan. Indikasi tangkap berlebih (overfishing) terhadap pemanfaatan sumber daya rajungan sudah mulai terlihat dari penurunan hasil tangkapan dan ukuran individu. Tulisan ini bertujuan mengetahui kondisi dan status stok sumber daya rajungan berdasarkan pada hasil penelitian yang dilakukan dari Februari sampai dengan November 2014 di perairan sekitar Pulau Belitung. Metode yang digunakan untuk penentuan status stok rajungan dengan menggunakan pendekatan metode Spawning Potential Ratio (SPR). Hasil penelitian menunjukkan bahwa status stok sumber daya rajungan di perairan sekitar Belitung mengalami penurunan yang ditunjukkan dengan hasil SPR 5% atau telah mengalami heavily exploited. Indikasi penurunan populasi juga ditunjukkan dengan nilai ratarata ukuran lebar karapas (CW) rajungan yang tertangkap (CW50) sebesar 93 mm, dibawah ukuran lebar karapas rata-rata pertama kali matang gonad (CWm) sebesar 118,9 mm. Upaya pemulihan stok dapat dilakukan dengan cara meningkatkan SPR pada level 10% dan 20% sebagai batas dan target pengelolaan untuk keberlanjutan sumber daya rajungan atau pada rata-rata ukuran lebar karapas (CW) rajungan yang tertangkap adalah 12 cm.</p><p><br /><em>The blue swimming crab (BSC) resources in waters around Belitung waters continously exploited as a livelihood resource. Intensive utilization of BSC resources can reduce the availability of stock in the waters. Indication of overfishing to the BSC resource have been seen by declining in catches </em><em>and individual size of BSC. The research aims to determine the condition and stock status of BSC resource based on the results of research conducted from February to November 2014 in the waters around the island of Belitung. The method used for determining the status of BSC stocks by using a method Spawning Potential Ratio (SPR). The result showed that stock status of BSC in the waters around Belitung decreased as indicated by the results of SPR 5% or has suffered heavily exploited. The indication of population decline is also indicated by the average value of the size of the carapace width (CW) at capture (L50) as 93 mm, it is below the average carapace width at first </em><em>maturity (Lm) as 118.98 mm. Stock recovery can be done by SPR at level 10% and 20% as biological sutainaibility as limist and target for management. It could reached if the minimal average value of the size of the carapace width of capture is 12 cm.</em></p>

scholarly journals Reproductive ecology, spawning potential, and breeding season of blue swimming crab (Portunidae: Portunus pelagicus) in Java Sea, Indonesia

2017 ◽  
Vol 18 (4) ◽  
pp. 1705-1713 ◽  
Author(s):  
TRI ERNAWATI ◽  
BAMBANG SUMIONO ◽  
HAWIS MADDUPPA
Keyword(s):  
Breeding Season ◽  
Reproductive Ecology ◽  
Carapace Width ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Short Period ◽  
Landing Sites ◽  
Spawning Potential Ratio ◽  
Java Sea ◽  
First Maturity

Ernawati T, Sumiono B, Madduppa H. 2017. Reproductive ecology, spawning potential, and breeding season of blue swimming crab (Portunidae: Portunus pelagicus) in Java Sea, Indonesia. Biodiversitas 18: 1705-1713. The blue swimming crab (Portunidae: Portunus pelagicus) is one of the most economically important fisheries species in Indonesia. Little is known about their reproductive ecology and key biological characteristics. This study aimed to investigate population biology and reproductive ecology (Carapace’s width to weight relationship, growth, natural mortality, size at first maturity and at first captured, Spawning Potential Ratio (SPR), and breeding season) of P. pelagicus at six important landing sites around the Java Sea (Jakarta, Cirebon, Demak, Rembang, Sumenep, and Sampit) from January 2014 to January 2015. Monthly data were collected by fishers at each landing sites, with a total of 14,408 individuals being measured. The study found that males were heavier than females and the smallest mean of individuals’ height belonged to Jakarta compared to other locations. The growth parameters varied at the different locations. Crabs could grow up to 100 mm in 10 months with the maximum age being less than three years. The growth rate (K) of more than 1 indicated a fast-growing crustacean with a short lifespan. The lowest carapace width at first capture (Lc) for the BSC was obtained from crabs caught using a bottom gillnet landed in Jakarta, followed by dredged crabs in Cirebon. The mean carapace width at first maturity (Lm) in the Java Sea was 10.6 cm, with the lowest Lm of female crabs being landed in Cirebon and the highest in Sampit. The Spawning Potential Ratio (SPR) ranged from 11% to 24% and the selectivity curve for the BSC fishery at each landing sites is positioned well to the right of the generic maturity curve, except in Demak, suggests that the operation enables almost all crabs to mature and spawn before entering the fishery. The collapsible trap was the most selective gear, with an average catch of 112 mm across at all landing sites, and the least selective was in trawls. Therefore consideration needs to be given to the different gear types used to catch crabs to leave smaller crabs in the water longer to grow to maturity. Considering its fast growth and peak season (February-April and August-October), a short-period is recommended at some sites that have been over-exploited to rebuild a broodstock to support the long-term sustainability of this species.

scholarly journals PARAMETER POPULASI UDANG PUTIH (Penaeus merguiensis) DI PERAIRAN SAMPIT DAN SEKITARNYA, KALIMANTAN TENGAH

2015 ◽  
Vol 7 (2) ◽  
pp. 103
Author(s):  
Erfind Nurdin ◽  
Duranta D Kembaren
Keyword(s):  
Mortality Rate ◽  
Stock Assessment ◽  
Total Mortality ◽  
Assessment Tools ◽  
White Shrimp ◽  
Population Parameter ◽  
Exploitation Rate ◽  
Shrimp Fisheries ◽  
Penaeus Merguiensis ◽  
Closed Season

Udang putih (Penaeus merguiensis)merupakan salah satu sumberdaya ekonomis penting di perairan Sampit. Pada saat ini alat tangkap yang efisien untukmenangkap udang adalah lampara dasar (danishseine) dan jaring tiga lapis (trammel net). Penelitian tentang tingkat pengusahaan udang putih telah dilakukan dari bulan Januari sampai bulan Nopember 2012. Penilaian estimasi parameter populasi udang putih menggunakan paket program “FAO – ICLARM Stock Assessment Tools” atau FISAT - II. Hasil analisis diperoleh nilai laju pertumbuhan (K) sebesar 1,45 per tahun dengan panjang karapas asimtotik (CL”) 57,8 mm. Laju kematian total (Z) sebesar 5,70 per tahun, laju kematian alamiah (M) sebesar 1,93 per tahun dan laju kematian akibat penangkapan (F) sebesar 3,77 per tahun. Tingkat pengusahaan udang putih di perairan Sampit telah mengalami lebih tangkap (over exploited) dengan nilai E sebesar 0,66. Udang putih sudah tertangkap terlebih dahulu sebelum mencapai ukuran pertama kali matang gonad (Lc=30,05 < Lm=39,4 mmCL). Kondisi ini mengindikasikan perlunya dilakukan pengelolaan yang hati-hati dan bertanggungjawab. Salah satu cara yang dapat ditempuh adalah denganmenerapkan sistem penutupan musim tangkapan, khususnya pada bulan Maret dan September, karena pada saat tersebut terjadi puncak pemijahan.White shrimp (Penaeus merguiensis) is one of the most valuable resources in the Sampit waters. At present danish seine and trammel net is an efficient gear available to catch shrimp. A study of exploitation of white shrimp was carried out from January to November 2012. Estimation of population parameter of white shrimp were analyzed by using program “FAO – ICLARM Stock Assessment Tools (FiSAT-II). The result showed that the value of growth rate (K) was 1.45/year with asymptotic carapace length (CL”) was 57.8 mm. Total mortality rate (Z) was 5.70/year, natural mortality rate (M) was 1.93/year and fishing mortality rate (F) was 3.77/year. Exploitation rate of white shrimp indicated overexploited (E=0.66). Moreover, these shrimp was fished before reaching the first size on maturity (Lc=30.05 < Lm=39.4 CLmm). This condition indicate that it is necessary to manage shrimp fisheries carefully and responsibly. It is recommended to apply a closed season system, especially on March and September when peak of spawning season occurred.

scholarly journals LAJU PERTUMBUHAN, LAJU KEMATIAN DAN EKSPLOITASI IKAN TONGKOL KOMO, Euthynnus affinis (Cantor 1849), DI PERAIRAN SAMUDERA HINDIA BARAT SUMATERA

2015 ◽  
Vol 6 (2) ◽  
pp. 69
Author(s):  
Irwan Jatmiko ◽  
Ririk Kartika Sulistyaningsih ◽  
Duto Nugroho
Keyword(s):  
Stock Assessment ◽  
Total Mortality ◽  
Assessment Tools ◽  
Instantaneous Rate ◽  
Exploitation Rate ◽  
The Indian Ocean ◽  
Euthynnus Affinis ◽  
The One ◽  
Base Data ◽  
Length Frequency Data

Tongkol komo (Euthynnus affinis Cantor, 1849)merupakan hasil tangkapan utama bagi nelayan pukat cincin di Samudera Hindia sebelah barat Sumatera. Penelitian ditujukan untukmemperoleh data dan informasi tentang estimasi laju pertumbuhan, laju kematian dan laju eksploitasi ikan tongkol komo. Analisis dilakukan berdasarkan himpunan data frekuensi panjang cagak sebanyak 1.325 ekor hasil tangkapan pukat cincin yang didaratkan di Pelabuhan Sibolga. Contoh ikan dikumpulkan secara bulanan dari bulan Juli 2012 hingga Februari 2013. Pendugaan parameter dilakukan menggunakan program FISAT II (FAO-ICLARM Stock Assessment Tools). Hasil kajian menunjukkan kisaran panjang cagak antara 30 - 60 cm, panjang asimptotik (L∞)= 63,5 cm, laju pertumbuhan(K) = 0,63/tahun dan umur teoritis pada saat panjang ke 0 ( t0 ) = -0,21 tahun. Estimasi laju kematian total tahunan (Z) sebesar 2,40/tahun, laju kematian alami (M) sebesar 1,07/tahun dan laju kematian akibat penangkapan(F) sebesar 1,33/tahun. Perkiraan Laju eksploitasi (E) = 0,55 mengindikasikan bahwa tingkat pemanfaatan berada pada tingkat yang moderat.Kawakawa (Euthynnus affinis Cantor, 1849) is the one of the major catch of fishermen in the Indian Ocean west off Sumatera. This study was aimed to investigate data and information on growth, mortality and the exploitation rates of kawakawa. Analyses were carried out based on a number of 1,325 length frequency data from purse seine fishery landed in Sibolga Fishing Port. Monthly base data were collected from July 2012 to February 2013. The specimens ranged from 30 to 60 cm FL. parameters were determined through a packageprogramof FISAT II (FAO-ICLARM StockAssessment Tools). The result showed that asymptotic length (L∞) were 63.5 cmFL, growth rates (K) 0.63/yr and estimated t0 -0.21 years. The annual instantaneous rate of total mortality (Z) was 2.40/yr, the natural mortality (M) was 1.07/yr and the fishing mortality (F) was 1.33/yr. The exploitation rate (E = 0.55) indicated that E. affinis was moderately exploited in the area.

scholarly journals DAMPAK EKONOMI KEBIJAKAN PEMBATASAN UKURAN RAJUNGAN (Portunus pelagicus) 10 cm DI BETAHWALANG, DEMAK

2016 ◽  
Vol 5 (3) ◽  
pp. 106-110
Author(s):  
Laily Fitriani ◽  
Abdul Ghofar ◽  
Dian Wijayanto
Keyword(s):  
Renewable Resource ◽  
Minimum Size ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Fish Resources ◽  
Fisheries Resources ◽  
Observation Methods ◽  
Collecting Methods ◽  
The Impact ◽  
High Fish

ABSTRAKSubsektor perikanan dapat berperan dalam pertumbuhan perekonomian bangsa Indonesia karena potensi sumberdaya ikan yang besar dalam jumlah dan keragamannya. Selain itu, sumberdaya ikan termasuk sumberdaya yang dapat diperbaharui dengan pengelolaan yang bijaksana, sehingga dapat terus dinikmati manfaatnya. Rajungan adalah salah satu jenis sumberdaya ikan yang potensial untuk dikembangkan. Selain harganya yang relatif tinggi, semua yang terkandung dalam tubuh rajungan juga dapat dikonsumsi. Oleh sebab itu, penangkapan rajungan oleh para nelayan dengan berbagai ukuran marak dilakukan. Penelitian ini bertujuan untuk menganalisis dampak ekonomi terhadap pembatasan ukuran rajungan (Portunus pelagicus) yang tertangkap dengan ukuran 10 cm di Desa Betahwalang, Demak. Penelitian dilakukan pada bulan Mei 2014 – Juni 2014 Di Betahwalang, Demak. Metode pengumpulan data yang digunakan adalah metode observasi, kuisioner dan wawancara langsung dengan nelayan. Responden dalam wawancara sebanyak 40 orang dengan hasil tangkapan yang berbeda-beda setiap trip-nya. Data yang diperoleh dari hasil wawancara kemudian diolah menggunakan statistikparametrik dengan membedakan dua variabel yaitu berat tangkapan (g) dan penerimaan (Rp) dengan regulasi dan tanpa regulasi. Kesimpulan dari penelitian ini membuktikan bahwa kebijakan pembatasan ukuran rajungan yang tertangkap  tidak berpengaruh secara signifikan terhadap hasil tangkapan nelayan, sehingga kebijakan tersebut dapat diterapkan. Kata Kunci : kebijakan, ukuran rajungan, regulasi ABSTRACT Fisheries sector can contribute for  economy growth of Indonesia because Indonesia have a high  fish resources, both in  the amount and diversity.Fish resources are  renewable resource and need to be managed wise for continue benefits. Blue swimming crab (Portunus pelagicus) is one of potential fisheries resources.  The blue swimming crab price is relatively high and all part of blue swimming crab crab body also can be consumed. Therefore, blue wimming crabs capture by the fishermen with various size is overexploited.This research purpose was to analys the scenario impact  of  restriction size blue swimming crab application (minimum size of 10 cm) in Betah Walang village, Demak. Research was be done at May 2014 to June 2014. Data collecting methods used observation methods, questionnaire and interview with fisherman. This reserach used 40 people as respondent. Then, data obtained was be analys use parametric statistic, both weight catch (g) and revenue  (Rp) with regulation and without regulation. This research proved if there were not significance difference as the impact of minimum size regulation application. Key words: policy, size of blue swimming crab, regulation

scholarly journals KARAKTERISTIK POPULASI DAN TINGKAT PEMANFAATAN KEPITING BAKAU (Scylla serrata Forskal 1775) DI PERAIRAN ASAHAN DAN SEKITARNYA, SUMATERA UTARA

2018 ◽  
Vol 24 (3) ◽  
pp. 165
Author(s):  
Andina Ramadhani Putri Pane ◽  
Ali Suman
Keyword(s):  
Mortality Rate ◽  
Stock Assessment ◽  
Carapace Width ◽  
Total Mortality ◽  
Population Characteristics ◽  
Assessment Tools ◽  
Scylla Serrata ◽  
Mud Crab ◽  
Length Frequency ◽  
Mangrove Crab

Peningkatan jumlah ekspor kepiting (Scylla serrata Forskal, 1775) di wilayah perairan Asahan memacu peningkatan penangkapan yang dapat berpengaruh terhadap populasi dan kelestarian. Penelitian ini bertujuan untuk mengetahui karakteristik populasi dan tingkat pemanfaatan kepiting bakau di perairan Asahan dan sekitarnya. Pengambilan sampel dilakukan setiap bulan dari Januari sampai dengan Nopember 2016 di tempat pendaratan kepiting oleh enumerator. Data dianalisa dengan metode Electronic LEngth Frequency Analisys-I (ELEFAN-I) dari FAO-ICLARM Stock Assessment Tools II (FiSAT II). Hasil penelitian menunjukkan pola pertumbuhan kepiting bakau bersifat allometrik negatif pada kisaran lebar karapas antara 85 - 175 mm dan bobot tubuh 127 – 1.152,5 gram. Rata-rata ukuran lebar karapas tertangkap dengan jaring dan bubu adalah 118,6 mm dan ukuran matang gonad pertama kali adalah 120,6 mm. Laju pertumbuhan (K) 1,38 per tahun dan lebar karapas maksimum (CW) sebesar 201 mm. Laju kematian total (Z) sebesar 3,59 per tahun, laju kematian karena penangkapan (F) dan laju kematian alami (M) masing-masing 2,27 per tahun dan 1,32 per tahun. Laju pemanfaatan (E) kepiting bakau di perairan Asahan adalah 0,63 per tahun atau sudah melebihi nilai optimum penangkapan. Agar sumber daya kepiting terjamin kelestariannya, maka harus dilakukan pengurangan upaya penangkapan sekitar 26 %.Increase in the volume of giant mud crab exports (Scylla serrata Forskal, 1775) in the Asahan waters stimulate the increasing catches that affect population and sustainability. This study aims to determine the population characteristics and the exploitation level of giant mud crab in Asahan and adjacent waters. Monthly sampling was done from January to November 2016 at crab landing sites by enumerator. The data were analyzed using Electronic Length Frequency Analysys-I (ELEFAN-I) method available in FAO-ICLARM Stock Assessment Tools II (FiSAT II) program. The results showed that the growth pattern of giant mud crab was negative allometric with carapace width between 85 - 175 mm and individual body weight 127 - 1,152.5 grams. The average carapace’s width caught by net and trap was 118.6 mm and the size of gonad first maturity was 120.6 mm. Growth rate (K) 1.38 per year and maximum carapace width (CW) of 201 mm. Total mortality rate (Z) of 3.59 per year, mortality rate due to fishing (F) and natural mortality rate (M) was 2.27 per year and 1.32 per year respectively. The rate of exploitation (E) of mangrove crab in Asahan waters was 0.63 or has exceeded the optimum value. For the sustainability of crab resource a reduction of 26% in fishing effort is suggested.

scholarly journals LAJU EKSPLOITASI IKAN TENGGIRI DAN TONGKOL DI KAWASAN KONSERVASI TAMAN NASIONAL KARIMUNJAWA

2017 ◽  
Vol 18 (1) ◽  
pp. 44-55
Author(s):  
Ernik Yuliana ◽  
Nurhasanah Nurhasanah
Keyword(s):  
Marine Protected Area ◽  
Stock Assessment ◽  
Assessment Tools ◽  
Fish Stock ◽  
Central Java ◽  
Scomberomorus Commerson ◽  
Exploitation Rate ◽  
Statistical Program ◽  
Euthynnus Affinis ◽  
Fish Stock Assessment

Karimunjawa National Park (KNP) is a marine protected area established to preserve ecosystems and natural resources. Scomberomorus commerson (tenggiri) and Euthynnus affinis (tongkol) arethe two species of pelagic fish which are the main catches for artisanal fishery in KNP. This study was aimed to analyze the exploitation rate of S. commerson and E. affinis. Field survey was conducted in KNP District of Jepara, Central Java, in June-September 2016. The exploitation rate is measured by analytical method based on fish’s growth and mortality, through measuring the length of the fish for three months.  Totally, as many as 314 individuals of S. Commersonand 499 individuals of E. Affinis were measured. The data were analyzed using Fish Stock Assessment Tools (FISAT II) statistical program. The results indicated that S. Commerson have a body-size trend that tends to increase, with the rate of exploitation (E) was 0,29 (under-exploited), which means there is anopportunity to increase it’s utilization. At the other hand, the size of E. Affinis tends to decrease, with the rate of exploitation (E) = 0,5. It means that the condition of utilizationof E. Affinis was at alarming position. It is necessary to control the tongkol fishing by regulating fishing gear, in order to avoid overfishing situation. Taman Nasional Karimunjawa (TNKJ) merupakan salah satu kawasan konservasi yang bertujuan melindungi kelestarian ekosistem dan sumber daya alam. Ikan tenggiri (Scomberomorus commerson)dan tongkol (Euthynnus affinis) adalah ikan pelagis yang merupakan tangkapan utama di TNKJ. Tujuan studi ini adalah menganalisis laju eksploitasi ikan tenggiri dan tongkol. Penelitian dilakukan pada bulan Juni-September 2016. Pengukuran laju eksploitasi menggunakan metode analitik didasarkan pada pertumbuhan dan mortalitas ikan, dengan mengukur panjang ikan hasil tangkapan selama tiga bulan. Jumlah ikan tenggiri yang diukur adalah 314 ekor, dan ikan tongkol adalah 499 ekor. Analisis data menggunakan program Fish Stock Assessment Tools (FISAT II). Hasil penelitian menunjukkan tren ukuran ikan tenggiri cenderung meningkat, dengan laju eksploitasi (E) = 0,29 (under exploited), sehingga pemanfaatannya dapat ditingkatkan. Sementara ukuran ikan tongkol cenderung menurun, dengan laju eksploitasi (E) = 0,5. Kondisi pemanfaatan ikan tongkol berada pada posisi mengkhawatirkan. Sehingga perlu dilakukan pengelolaan terhadap penangkapan ikan tongkol agar tidak mengarah ke penangkapan berlebih, dengan mengatur alat tangkap nelayan.  

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