scholarly journals VARIABILITY OF CARAPACE WIDTH SIZE AND ABUNDANCE OF BLUE SWIMMING CRABS (Portunus pelagicus Linnaeus) IN PATI WATERS

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Dyah Ika Nugraheni ◽  
Achmad Fahrudin ◽  
. Yonvitner

Fishing effort enhancement would put pressure on blue swimming crab resources and its ecosystem. The objective of this study was to determine the spatial distribution based on the size of the carapace width (CW), abundance, temperature, salinity, depth, and fishing intensity in Pati waters which was divided into two zones (zones 1=nearshore, zone 2=offshore). The result showed that the average of carapace width in zone 1 to zone 2 was significantly different (p <0.05), as well as between males and females. Average number of individual (abundance) was significantly different according to fishing areas and sex (p <0.05). The average of water temperature in zone 1 was higher than in zone 2, salinity in zone 1 was smaller than in zone 2, and the water depth in zone 1 was shallower than in zone 2. The higher the crab catch intensity leaded to the smaller the abundance and size of carapace width. Alternative management strategies were proposed such as to divert fishing grounds from coastal waters to offshore during low productivity season, to uphold rules on minimum legal size for catching (Lm = 107 mm),  to release of berried females catch, and to reduce accretion rate of gear and fishing fleet mainly in the coastal zone waters.Keywords:  blue swimming crab, carapace widht (CW), abundance, intensity of fishing

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Dyah Ika Nugraheni ◽  
Achmad Fahrudin ◽  
. Yonvitner

<p><em>Fishing effort enhancement would put pressure on blue swimming crab resources and its ecosystem. The objective of this study was to determine the spatial distribution based on the size of the carapace width (CW), abundance, temperature, salinity, depth, and fishing intensity in Pati waters which was divided into two zones (zones 1=nearshore, zone 2=offshore). The result showed that the average of carapace width in zone 1 to zone 2 was significantly different (p &lt;0.05), as well as between males and females. Average number of individual (abundance) was significantly different according to fishing areas and sex (p &lt;0.05). The average of water temperature in zone 1 was higher than in zone 2, salinity in zone 1 was smaller than in zone 2, and the water depth in zone 1 was shallower than in zone 2. The higher the crab catch intensity leaded to the smaller the abundance and size of carapace width. Alternative management strategies were proposed such as to divert fishing grounds from coastal waters to offshore during low productivity season, to uphold rules on minimum legal size for catching (Lm = 107 mm),  to release of berried females catch, and to reduce accretion rate of gear and fishing fleet mainly in the coastal zone waters.</em></p><p><em><strong><em>Keywords:  </em></strong><em>blue swimming crab, carapace widht (CW), abundance, intensity of fishing</em></em></p>


2020 ◽  
Vol 26 (1) ◽  
pp. 51
Author(s):  
Ali Suman ◽  
Ap'idatul Hasanah ◽  
Andina Ramadhani Putri Pane ◽  
Pratiwi Lestari

A study on the stock status of blue swimming crab (Portunus pelagicus Linnaeus, 1758) was conducted in Tanah Laut, South Kalimantan waters, based on data collected in March to November 2017. The results showed that the growth pattern of blue swimming crab in Tanah Laut waters was negatively allometric and the sex ratio of males to females was 1.0 : 1.7. The chi-square test indicated that the total males and total females of the blue swimming crab was significantly different. It means that there was an imbalance in numbers between males and females. The estimated length at first capture (Lc) was 127.26 mm (carapace width; CW), smaller than the length at first maturity (Lm) at 133.24 mmCW. The growth parameter of blue swimming crab was 1.1year with a maximum carapace width (L) of 204.3 mmCW. The estimated instantaneous total mortality (Z) and natural mortality (M) were 3.04/year and 1.24/year, respectively. While fishing mortality (F) and exploitation rate (E) were 1.80/year and 0.59/year, respectively, the estimated spawning potential ratio (SPR) was 11.1 %. Therefore, the stock status was categorized as overfishing. In order to ensure the sustainability of the blue swimming crab, a precautionary approach,, such as reducing fishing effort by 18 % of the current situation, is strongly recommended to apply.


2018 ◽  
Vol 6 (1) ◽  
pp. 149
Author(s):  
Frank Rijkaard Makahinda ◽  
Rose O.S.E Mantiri ◽  
Boyke H. Toloh

Portunus pelagicus (blue swimming crab) is one of the important economical marine commodities produced from Indonesian coastal waters that has increasing market demand among fishery commodities. The purpose of this research is to reveal the relationship of carapace width and weight, the growth pattern and the carapace width-weight ratio of P. pelagicus crabs at two different research sites in Manado Bay. The benefits of this study, can be a reference for further studies on blue swimming crabs, P. pelagicus, and information obtained in this study could become important information needed for the maximum sustainable utilization of blue swimming crab, P. pelagicus.This research was conducted at two locations, namely Kelurahan Bahu, Sub-district of Malalayang with coordinates of 1 ° 27'49.86 "North and 124 ° 49'35.79" East and second location in Tumumpa Dua, Sub-district of Tuminting with coordinates 1 ° 31'14.51"North - 124 ° 50'28.67"East. Samples of blue swimming crabs were collected by deploying traps which are placed at 5-7 meters with the distance between traps 10 meter. Traps were placed at 17.00 pm and lifted on the next day at 06.00 am. Measurement of the width of the carapace conducted by using the ruler with 0.1 cm accuracy and weight measurement using the scales with 0.1 gram accuracy.The correlation value obtained for the wide and weight relationship of blue swimming crabs in the Sub-district of Malalayang is 0.953 for males and 0.898 for females. In Kelurahan Tumumpa Dua, Sub-dis ittrict of Tuminting 0.829 for males and 0.920 for females respectively. Based on these values the increase in the width of the carapace will affect the weight gain of the crab. The growth pattern of P. pelagicus crab in Kelurahan Bahu, Sub-district of Malalayang and Tumumpa Dua Sub-district Tuminting showed negative allometric growth pattern with b <3 value which means faster carapace growth compared to the weight of crab. From the result of chi square test on wide body and weight relationship analysis, is found same for both locations with value x2 table = 7.815 <x2 count = 112.3134. This is presumably due to one of the external factors is the availability of food.Keywords: Rajungan, growth pattern, Manado Bay AbstrakPortunus pelagicus merupakan salah satu komoditi hasil laut ekonomis penting yang dihasilkan dari perairan pantai Indonesia dengan permintaan pasar terhadap komoditas rajungan yang terus meningkat. Adapun tujuan penelitian ini yaitu mengetahui hubungan lebar berat rajungan P. pelagicus, pola pertumbuhan rajungan P. pelagicus dan perbandingan lebar berat rajungan P. pelagicus di dua lokasi penelitian yang berbeda di Teluk Manado. Manfaat penelitian ini, dapat menjadi bahan acuan untuk studi lebih lanjut mengenai rajungan P. pelagicus serta infomasi yang didapat dalam penelitian ini bisa menjadi bahan kajian untuk pemanfaatan rajungan P. pelagicus secara maksimal serta berkelanjutan.Penelitian ini dilaksanakan pada dua lokasi yakni di Kelurahan Bahu Kecamatan Malalayang dengan koordinat 1°27'49.86"LU - 124°49'35.79"BT dan lokasi kedua di Kelurahan Tumumpa Dua Kecamatan Tuminting dengan koordinat 1°31'14.51"LU - 124°50'28.67"BT. Pengambilan sampel dilakukan dengan alat tangkap bubu yang diletakan pada kedalam 5-7 meter dengan jarak antara bubu 10 meter. Bubu diletakan pada pukul 17.00 wita dan diangkat pada esok harinya pukul 06.00 wita. Pengukuran lebar karapas menggunakan mistar dengan ketelitian 0,1 cm dan pengukuran berat tubuh menggunakan timbangan 0,1 gr.Nilai korelasi yang didapat untuk hubungan lebar berat rajungan P. pelagicus di Kelurahan Bahu Kecamatan Malalayang 0,953 untuk jantan dan 0,898 untuk betina. Di Kelurahan Tumumpa Dua Kecamatan Tuminting 0,829 untuk jantan dan 0,920 untuk betina. Berdasarkan nilai tersebut pertambahan lebar karapas akan berpengaruh pada kenaikan berat tubuh dari rajungan. Pola pertumbuhan rajungan P. pelagicus di Kelurahan Bahu Kecamatan Malalayang dan di Kelurahan Tumumpa Dua Kecamatan Tuminting menunjukan pola pertumbuhan yang bersifat allometrik negatif dengan nilai b < 3 yang berarti pertumbuhan karapas lebih cepat dibandingkan pertambahan berat rajungan. Dari hasil analisis chi square lebar berat tubuh, sama untuk kedua lokasi penelitian dengan nilai x2 tabel =  7,815 < x2 hitung = 112,3134. Hal ini diduga karena salah satu faktor eksternal yakni  ketersediaan makanan.Kata  kunci : Rajungan,  Pola pertumbuhan, Teluk Manado.


Author(s):  
Fransisco P.T. Pangalila ◽  
Ivor L. Labaro

Swimming Crab (Portunus pelagicus) is one of the economically important marine commodities produced from the coastal waters of Indonesia. The Catching of swimming crabs directly from nature carried out using various types of fishing gear, one of which is a trap. Methods using experimental methods. Therefore, the objective of this research was to study the effect of  type of bait to catch swimming crab. Two kinds of bait, the scad mackerel and chicken intestines. Catch data were collected using 6 units of  trap, operated in coastal waters of Manado bay; and data analysis is based on a  t-test is done using a comparative analysis of the value of the middle observation sample pairs. Besides evaluation carapace size and weight (legal size) swimming crab based Permen KP nomor 1 tahun 2015. The catch was 76 swimming crabs in total, and the results of t-test analysis showed that the use of bait scad mackerel and chicken intestines on traps caused high significant effect in catch. The size of swimming crabs showed that nearly all eligible allowable catch of 71 individuals (93%) both carapace size and weight, and only 5 individuals (7%) who do not eligible allowable catch. Keywords : swimming crab, carapace size, trap baits, chicken intestines.   ABSTRAK Rajungan (Portunus pelagicus) merupakan salah satu komoditi hasil laut ekonomis penting yang dihasilkan dari perairan pantai Indonesia.  Penangkapan rajungan langsung dari alam dilakukan dengan menggunakan berbagai jenis alat tangkap, salah satunya adalah bubu.  Metode Penelitian menggunakan metode eksperimental. Penelitian ini bertujuan untuk mempelajari pengaruh jenis umpan terhadap hasil tangkapan rajungan. Dua jenis umpan yang digunakan, yaitu ikan layang dan usus ayam. Data tangkapan dikumpulkan dengan menggunakan 6 unit bubu, yang dioperasikan di perairan pantai Malalayang Teluk Manado; dan analisis data didasarkan pada uji t yang dikerjakan menggunakan analisis perbandingan nilai tengah contoh pengamatan berpasangan.  Selain itu dilakukan evaluasi ukuran karapas dan berat (legal size) rajungan berdasarkan Permen KP nomor 1 tahun 2015. Total hasil tangkapan 76 ekor, dan hasil analisis uji t menunjukkan bahwa penggunaan umpan ikan layang dan usus ayam pada bubu kerucut memberikan hasil tangkapan rajungan yang sangat berbeda nyata.  Ukuran hasil tangkapan rajungan yang diperoleh menunjukkan bahwa hampir semuanya memenuhi persyaratan tangkapan yang diperbolehkan yaitu 71 ekor (93 %) baik ukuran karapas maupun berat, dan hanya 5 ekor (7 %) yang tidak memenuhi persyaratan. Kata-kata kunci : rajungan, ukuran karapas, umpan bubu, usus ayam.


Author(s):  
Adi Susanto ◽  
Ririn Irnawati ◽  
Mustahal ◽  
Hery Sutrawan Nurdin ◽  
Yeni Marliana ◽  
...  

Blue swimming crab (Portunus pelagicus) is an important economical fishery commodity for fishermen in Banten Bay that are caught using gill nets and collapsible traps. The increasing of fishing pressure has highly potential to reduce the quality of the catch as exposed in previous studies. However, the comprehensive, and time series analysis of the previous research results have not been conducted. The purpose of this study is to analyze the variations of blue swimming crab caught in Banten Bay through a combination of meta-analysis techniques, fishing trials and field obser-vations to determine the effect of fishing activities on swimming crab sizes, and evaluate the status of swimming crab fisheries in Banten Bay. Standard mean difference from 10 different studies was used as a meta-analysis parameter. The results of the meta-analysis showed that fishing activities were conducted from 2004 to 2018 had a significant effect on the decreasing of the swimming crab size. The average of swimming crab carapace width caught in 2019 approximately 121.66 mm. The proportion of legal swimming crabs in 2014, 2015 and 2019 was more than 80%, so that the status of swimming crab fisheries in Banten Bay is still environmentally friendly.Keywords: carapace width, meta analysis, fisheries, Portunus pelagicus, blue swimming crab


Author(s):  
. Ihsan ◽  
Eko Sri Wiyono ◽  
Sugeng Hari Wisudo ◽  
John Haluan

<p>ABSTRACT<br />The season patern of swimming crab is influenced by rekruitman amount generated by each individual crab in the fishing ground. This study aims to assess the pattern of fishing crab season and the fishing ground as a participatory method in Pangkep water Regency. The data collected consisted of primary and secondary data. Data analysis was performed using the technique of time series analysis on the catch per unit of fishing effort crab monthly during the last six years. The peak season is catching crabs at IMP&gt; 1% which took place in June and September. The highest percentage of catches in the fishing ground is in September which is 11.71% and lowest in April which amounted to 5.77%. The results of the analysis of index fishing season of crabs is throughout the year at the fishing area in Pangkep waters.</p><p>Keywords: Analysis, Season Patern, Fishing Ground, Swimming Crabs</p><p>-------</p><p><br />ABSTRAK</p><p>Pola musim rajungan dipengaruhi oleh jumlah rekruitman yang dihasilkan oleh setiap individu rajungan di daerah penangkapan. Penelitian ini bertujuan untuk mengkaji pola musim penangkapan rajungan dan daerah penangkapan rajungan secara partisipatif di perairan Kabupaten Pangkep. Data yang dikumpulkan terdiri dari data primer dan data sekunder. Analisis data yang dilakukan adalah menggunakan teknik analisis deret waktu (time series) terhadap hasil tangkapan per satuan upaya penangkapan bulanan rajungan selama enam tahun terakhir. Musim puncak penangkapan rajungan berada pada IMP &gt; 1 % yakni berlangsung pada bulan Juni dan September. Persentase tangkapan tertinggi di daerah penangkapan adalah pada bulan September yakni 11,71 % dan terendah pada bulan April yakni sebesar 5,77 %. Hasil analisis indeks musim penangkapan (IMP) rajungan dilakukan sepanjang tahun di daerah penangkapan di perairan Kabupaten Pangkep.</p><p><br />Kata kunci: Analisis; Pola Musim; Daerah Penangkapan; Rajungan</p>


Author(s):  
S. S. K. Haputhantri ◽  
S. J. W. W. M. M. P. Weerasekera ◽  
K. H. K. Bandaranayake

The blue swimming crab (Portunus pelagicus) has become the focus of an important export-oriented fishery in Sri Lanka for a decade. The Palk Bay in the Northern coastal waters of Sri Lanka is one of the best-known fishing grounds for blue swimming crabs in Sri Lanka. This study was undertaken with the aim of establishing some morphometric relationships for P. pelagicus in the Palk Bay. Biological sampling was conducted for five consecutive days per month from November 2014 - October 2015 in the Northern landing sites in the Jaffna District where the catch of Palk Bay blue swimming crab fishery was landed. P. pelagicus specimens were also randomly collected for laboratory analysis. The morphometric measurements of the specimens for the following parameters were undertaken: CW - carapace width with the spine, CWW - carapace width without spine, MW – mouth width, TL - total length, LCPL - left chelar propodus length, LMOV - left movable part Length, RMOV - right movable part length, LCPH - left chelar propodus height, RCPH - right chelar propodus height, ABW - abdominal width, ABL - abdominal length and BW - body weight. The least squared method was used to obtain the Length-Length (L-L) and Length-Weight (L-W) relationships. Of the 65 L-L relationships obtained for P. pelagicus from the study, 34 relationships were correlated (r2>0.5). The estimated relationships between BW and CW for males and females were BW=0.0001 CW 3.01 (r2 =0.84) and BW= 0.0001 CW 2.90 (r2 =0.86), respectively. Positive allometric growth was observed for male P. pelagicus, whereas a negative allometric growth was observed for female P. pelagicus. Most of the morphometric relationships of P. pelagicus obtained in this study were not isometric.


Author(s):  
Maichel Arvan Pananggung ◽  
Ivor L. Labaro ◽  
Emil Reppie

ABSTRACT Mangrove crab (Scylla serrata) and swimming crab (Portunus pelagicus) are economically important marine commodities produced from the coastal waters of Sangihe Islands Regency. But those marine commodity products are usually only caught accidentally with a bottom gill net. There has been a special trap fishing gear for that resources, but not known well by local fishermen. Addition of squid oil extraction baits could increase the fishing power of mangrove crab and swimming crab traps. This research aims to study the effect of squid oil extract on traps bait to catch mangrove crab and swimming crab; and identify the types of biota captured. This research was done in coastal waters of Malise village, Tabukan Tengah District of Sangihe Islands Regency for 2 weeks September 2015; based on experimental method. Six unit traps were operated ten trips where three units of them used scad mackerel bait that injected with squid oil extract, and tree other units just used scad mackerel bait without extract; and the capture data were analyzed using t test. The catch was 142 individuals (135 mangrove crabs and 7 swimming crab); where 86 crabs was caught by scad mackerel bait with squid oil extract, and 56 crabs caught with bait without squid oil extract. The analysis showed that the use of squid oil extracts on trap baits increased the catch. Keywords: mangrove crab, swimming crab,trap baits, squid oil extract, Sangihe   ABSTRAK[1] Kepiting bakau (Scylla serrata) dan rajungan (Portunus pelagicus) merupakan komoditi hasil laut ekonomis penting yang dihasilkan dari perairan pantai Kabupaten Kepulauan Sangihe. Tetapi komoditi hasil laut tersebut biasanya hanya tertangkap tanpa sengaja (by catch) dengan jaring insang dasar. Sebenarnya telah ada alat tangkap bubu khusus untuk kepiting bakau dan rajungan, tetapi belum dikenal oleh nelayan lokal. Pemberian ekstrak minyak cumi pada umpan, diduga dapat meningkatkan kemampuan tangkap dari bubu kepiting bakau dan rajungan. Penelitian ini bertujuan untuk mempelajari pengaruh ekstrak minyak cumi pada umpan bubu terhadap hasil tangkapan kepiting bakau dan rajungan, dan mengidentifikasi jenis-jenis biota yang tertangkap. Penelitian ini dilakukan di perairan Malise Kecamatan Tabukan Tengah, Kabupaten Kepulauan Sangihe; selama 2 minggu pada bulan September 2015; yang didasarkan pada metode eksperimental. Enam unit bubu dioperasikan selama sepuluh trip untuk mengumpulkan data; di mana tiga unit menggunakan umpan ikan layang yang disuntikan ekstrak minyak cumi, dan tiga unit lainnya hanya menggunakan umpan ikan laying tanpa ekstrak; dan data dianalisis dengan uji t. Tangkapan total berjumlah 142 ekor (135 ekor kepiting bakau dan 7 ekor rajungan); di mana 86 ekor tertangkap dengan umpan layang yang diberi ekstrak minyak cumi, dan 56 ekor tertangkap dengan umpan tanpa ekstrak. Hasil analisis menunjukkan bahwa penggunaan ekstrak minyak cumi pada umpan bubu, memberikan hasil tangkapan yang sangat berbeda dibandingkan dengan umpan tanpa ekstrak minyak cumi. Kata-kata kunci: kepiting bakau, rajungan, umpan bubu, ekstrak minyak cumi, Sangihe  


2019 ◽  
Vol 8 (4) ◽  
pp. 402-408
Author(s):  
Nathanael Ganang Anindityo Wibowo ◽  
Chrisna Adhi Suryono ◽  
Ibnu Pratikto

Rembang merupakan salah satu kabupaten di Jawa Tengah yang dikenal sebagai daerah penghasil sumberdaya rajungan yang cukup tinggi permintaannya dan terus meningkat setiap tahunnya. Hal tersebut dapat menyebabkan terjadinya penurunan potensi hasil rajungan akibat intensifnya penangkapan di Perairan Rembang. Kajian tentang kondisi stok sumberdaya rajungan  terkait sebaran dan dinamika populasi ini sangat diperlukan dalam pengelolaan potensi rajungan. Tujuan dari penelitian ini adalah untuk menganalisis struktur ukuran dan parameter pertumbuhan rajungan di Perairan Rembang. Penelitian ini dilaksanakan pada bulan Maret – Juni 2019 di Perairan Rembang, dengan menggunakan metode survei yang bersifat deskriptif. Total sampel rajungan selama penelitian adalah 1200 ekor yang terdiri dari 574 ekor jantan dan 624 ekor betina. Hasil penelitian menunjukkan kelas ukuran lebar karapas rajungan didominasi oleh rajungan muda, dengan rata – rata 105.01 ± 11.99 mm untuk jantan dan 107.73 ± 10.68 untuk betina. Berat rata – rata rajungan jantan yaitu sebesar 95.2 ± 27.1 gram dan rajungan betina sebesar 97.9 ± 23.1 gram, sehingga menunjukkan rajungan jantan lebih kecil dibandingkan dengan rajungan betina. Pola pertumbuhan rajungan di Perairan Rembang bersifat allometrik negatif. Laju pertumbuhan rajungan di Perairan Rembang yang didapatkan adalah berupa nilai panjang asimptotik (L∞) sebesar 71.4 mm dengan koefisien pertumbuhan (K) sebesar 1.5/tahun.Rembang is a coastal region in Central Java which known as to producer of blue swimming crab resources that are in high demand and continues to increase every year. It will because decreasing the potential yield of blue swimming crab due to intensive fishing in Rembang Waters. Study on the stock condition of the blue swimming crab resource related to the distribution and dynamics of the population is required for the management of the blue swimming crab potential. The current research aims to assess the size structure and growth parameter of blue swimming crab in the Rembang Waters. The research was conducted from March to June 2019 in Rembang Waters, using a descriptive survey method. The total number of crab samples during the study was 1200 animals consisting of 574 male and 624 female. The results showed that the size of the crab carapace width class was dominated by young crabs, with an average of 105.01 ± 11.99 mm for males and 107.73 ± 10.68 for females. The average weight of male crab is 95.2 ± 27.1 gram and female crab is 97.9 ± 23.1 gram, indicates that male crab is smaller than female crab. The crab’s growth in Rembang Waters is allometric negative. The growth rate of crab in the Rembang Waters obtained is in the form of asymptotic length (L∞) was 71.4 mm with a growth coefficient (K) 1.5/year.


2020 ◽  
Vol 25 (2) ◽  
pp. 85-90
Author(s):  
Yustika Permatahati Intan Permatahati ◽  
Nila Nikmatia Bugis ◽  
La Sara ◽  
Tezza Fauzan Hasuba Hasuba

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. 


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