scholarly journals Growing Pattern of Blue Swimming Crab, Portunus pelagicus at Two Different Locations in Manado Bay

2018 ◽  
Vol 6 (1) ◽  
pp. 149
Author(s):  
Frank Rijkaard Makahinda ◽  
Rose O.S.E Mantiri ◽  
Boyke H. Toloh
Keyword(s):  
Growth Pattern ◽  
Carapace Width ◽  
Market Demand ◽  
Swimming Crab ◽  
Chi Square ◽  
Portunus Pelagicus ◽  
Relationship Analysis ◽  
Weight Relationship ◽  
Relationship Of ◽  
Swimming Crabs

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.

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
Keyword(s):  
Coastal Waters ◽  
Accretion Rate ◽  
Carapace Width ◽  
Management Strategies ◽  
Fishing Effort ◽  
Swimming Crab ◽  
Nearshore Zone ◽  
Portunus Pelagicus ◽  
Males And Females ◽  
Swimming Crabs

<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>

scholarly journals Kajian Tingkat Kerentanan Rajungan (Portunus pelagicus) di Perairan Desa Tunggulsari Kabupaten Rembang

2021 ◽  
Vol 10 (1) ◽  
pp. 147-157
Author(s):  
Parameswari Iccha Nirmalabuddhi Wishnuputri ◽  
Sri Redjeki ◽  
Retno Hartati
Keyword(s):  
Water Quality ◽  
Growth Pattern ◽  
Economic Value ◽  
Quality Parameters ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female ◽  
Over Exploitation ◽  
The Village ◽  
Swimming Crabs

Rajungan (Portunus pelagicus) adalah salah satu sumber daya hayati laut Indonesia. Rajungan merupakan komoditas utama  perikanan di Indonesa, baik untuk lokal maupun ekspor. Nilai ekonomis rajungan yang tergolong tinggi mengakibatkan penangkapan rajungan dilakukan secara besar-besar dan dapat memicu terjadinya kepunahan. Penelitian bertujuan untuk mengetahui tingkat kerentanan rajungan di Perairan Desa Tunggulsari dan mengetahui karakteristik morfometri dari rajungan yang ditangkap pada lokasi tersebut. Metode yang digunakan dalam penelitian ini adalah metode Productivity and Susceptibility Analysis (PSA). Wawancara dilakukan kepada 60 nelayan di Desa Tunggulsari. Pengukuran parameter kualitas perairan meliputi suhu, oksigen terlarut, salinitas, dan pH. Pengukuran morfometri dilakukan pada salah satu pengepul di desa. Hasil dari wawancara diketahui bahwa nelayan di Desa Tunggulsari menggunakan 2 macam alat tangkap yaitu bubu lipat dan jaring insang dasar. Penilaian atribut produktivitas rajungan masuk dalam kategori tinggi, sedangkan penilaian atribut kerentanan tergolong pada resiko rendah untuk penggunaan kedua alat tersebut. Nilai MSC untuk alat tangkap bubu lipat adalah 96,0 dan 98,2 untuk alat tangkap jaring insang dasar. Nilai MSC > 80 menunjukkan bahwa tingkat kerentanan rajungan pada lokasi tersebut masuk pada kategori rendah. Selanjutnya, pola pertumbuhan rajungan di Desa Tunggulsari adalah allometrik negatif baik untuk rajungan jantan maupun betina. Hal ini menunjukkan pertumbuhan panjang dan lebar karapas lebih cepat dibandingkan penambahan berat rajungan. The blue swimming crab (Portunus pelagicus) is one of the Indonesian marine biological resources. The blue swimming crab is a main commodity of fisheries in Indonesia, both for local and export. Economic value of blue swimming crab classified as high involve over-exploitation of blue swimming crab and can lead to extinction. This research is aimed to determine level of vulnerability of blue swimming crab in Tunggulsari waters and to discover morphometry characteristic of blue swimming crab that caught at that location. The method used in this research is Productivity and Susceptibility (PSA) method. Interviews were conducted with 6 fishermen in the village of Tunggulsari. Measurement of water quality parameters including temperature, dissolved oxygen, salinity, and pH. Morphometry measurement was carried out in one of the collectors in the village. The results of the interview revealed that fishermen in the village of Tunggulsari used 2 fishing tools namely bubu lipat and bottom set gillnet. Assessment of blue swimming crab productivity attributes is included in the high category, while the assessment of vulnerability attributes is classified as low risk for the use of both tools. The MSC value for bubu lipat is 96,0 and 98,2 for bottom set gillnet. The MSC value is more than 80 indicates that the level of blue swimming crab vulnerability at that location is in the low category. Further, blue swimming crab growth pattern in the village of Tunggulsari are negative allometrics for both male and female blue swimming crabs. This shows the growth in length and width carapace is faster than the addition of blue swimming crab weight.

scholarly journals STOCK STATUS OF BLUE SWIMMING CRAB (Portunus pelagicus) IN TANAH LAUT, SOUTH KALIMANTAN, AND ITS ADJACENT WATERS

2020 ◽  
Vol 26 (1) ◽  
pp. 51
Author(s):  
Ali Suman ◽  
Ap'idatul Hasanah ◽  
Andina Ramadhani Putri Pane ◽  
Pratiwi Lestari
Keyword(s):  
Carapace Width ◽  
Total Mortality ◽  
Growth Parameter ◽  
Fishing Effort ◽  
Swimming Crab ◽  
Chi Square ◽  
Portunus Pelagicus ◽  
Stock Status ◽  
Chi Square Test ◽  
First Maturity

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.

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 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
Keyword(s):  
Coastal Waters ◽  
Accretion Rate ◽  
Carapace Width ◽  
Management Strategies ◽  
Fishing Effort ◽  
Swimming Crab ◽  
Nearshore Zone ◽  
Portunus Pelagicus ◽  
Males And Females ◽  
Swimming Crabs

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

scholarly journals META ANALISIS PENGARUH TEKANAN PENANGKAPAN TERHADAP UKURAN RAJUNGAN (Portunus pelagicus) DI TELUK BANTEN

2019 ◽  
Vol 10 (2) ◽  
pp. 153-163
Author(s):  
Adi Susanto ◽  
Ririn Irnawati ◽  
Mustahal ◽  
Hery Sutrawan Nurdin ◽  
Yeni Marliana ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Carapace Width ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Analysis Techniques ◽  
Standard Mean Difference ◽  
The Status ◽  
Obser Vations ◽  
Swimming Crabs

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

scholarly journals Rasio Jenis Kelamin dan Tingkat Kematangan Gonad pada Rajungan (Portunus pelagicus) Linnaeus, 1758 (Malacostraca:Portunidae) yang Didaratkan di Kelurahan Pacar, Kabupaten Rembang

2020 ◽  
Vol 9 (1) ◽  
pp. 1-8
Author(s):  
Sri Devi Simanjuntak ◽  
Ervia Yudiati ◽  
Subagiyo Subagiyo
Keyword(s):  
Size Structure ◽  
Economic Value ◽  
Swimming Crab ◽  
Maturity Level ◽  
Chi Square ◽  
Portunus Pelagicus ◽  
Male And Female ◽  
Gonad Maturity ◽  
The Village ◽  
Swimming Crabs

ABSTRAK : Rajungan (Portunus pelagicus) memiliki nilai ekonomi tinggi, dimana berbanding lurus dengan penangkapan yang meningkat. Tingkat pemanfaatan yang tidak mengindahkan ukuran dan kondisi rajungan dapat mempengaruhi struktur ukuran dan stok rajungan di suatu perairan. Penelitian ini bertujuan untuk melakukan kajian morfometri, rasio jenis kelamin dan tingkat kematangan gonad rajungan yang didaratkan di Kelurahan Pacar, Kabupaten Rembang. Metode yang digunakan dalam penelitian bersifat deskriptif dan eksploratif. Pengamatan rajungan dilakukan pada salah satu pengepul di Kelurahan Pacar. Rajungan yang diteliti berdasarkan morfometri, rasio seksual dan tingkat kematangan gonad selama 30 hari. Informasi ini dapat dijadikan pedoman dalam menentukan kebijakan mengenai pengelolaan perikanan rajungan yang berkelanjutan. Hasil dari penelitian diketahui bahwa ratio kelimpahan rajungan jantan sebesar 45% (1342 ekor); rajungan betina 55% (1658 ekor) dari 3000 ekor sampel rajungan. Rasio perbandingan jantan dan betina 0,80:1 berdasarkan uji chi square. Berdasarkan distribusi ukuran lebar karapas rajungan di perairan Kelurahan Pacar adalah berkisar antara 60–179 mm dan distribusi berat sebesar 23–251 gram. Distribusi tingkat kematangan gonad pada perairan Kelurahan Pacar adalah 558 ekor pada TKG 1; 761 ekor pada TKG 2; dan 339 pada TKG 3. Data menunjukkan bahwa pola pertumbuhan rajungan yang ada di perairan Kelurahan Pacar adalah allometrik negatif yaitu pertumbuhan lebar karapas lebih cepat bertambah daripada berat tubuhnya baik rajungan jantan maupun rajungan betina.ABSTRACT : Blue swimming crab (Portunus pelagicus) has a high economic value, which is causing the crab catch to rise as well. The catch rate that does not consider the size and maturity of sea crab can affect the size structure and population stock of sea crab in waters. This research to study morphometry, sexual ratio and maturity level of the gonads landed in Pacar Village, Rembang Regency.The method used in this study descriptive and exsplorative. Observation of blue swimming crab samples was carried out in one of the collectors in the village. Blue swimming crab was observed based on morphometry and sexual ratio for 30 days. The results of the study revealed that the abundance of male blue swimming crab was 45% (1342 male blue swimming crabs) and the abundance of the female blue swimming crabs was 55%  (1658 female blue swimming crabs) of 3000 blue swimming crab samples. The ratio of male and female   0.80 ; 1 based on the chi square. Based on the size distribution of the width of the blue swimming crab carapace in the waters of Pacar Village it range from 60-179 mm and the distribution of weight 23-251 grams. The distribution of gonad maturity level in the waters Pacar Village is 558 female blue swimming crab at TKG 1; 761 female blue swimming crab at TKG 2; and 339 female blue swimming crab at TKG 3. Data is showed that the blue swimming crab growth pattern in Pacar Village waters was negative allometric both male and female blue swimming crab.

scholarly journals Carapace Width -Weight Relationship Of Mud Crab Scylla Serrata (Forskal, 1775) Collected From Pulicat Lake, Tamilnadu, India

2016 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
V. Lakshme Gayathre ◽  
S. Felix ◽  
R. Durairaja
Keyword(s):  
Body Weight ◽  
Growth Pattern ◽  
Tamil Nadu ◽  
Carapace Width ◽  
Scylla Serrata ◽  
Mud Crab ◽  
Pulicat Lake ◽  
Weight Relationship ◽  
Relationship Of ◽  
The Relationship

<div><p><em>Mud crab Scylla serrata form an important fishery in the Pulicat lake, Tamilnadu. In the present study the relationship between carapace width and body weight were estimated as <strong>(Log W= -0.342438+2.914702)</strong>. The estimated <strong>‘a’</strong> and <strong>‘b’</strong> value for carapace width and body weight were <strong>-0.342438</strong> and <strong>2.914702</strong>, respectively. The result showed an isometric growth pattern and significant differences were found between carapace width and body weight in the mud crab collected from Pulicat lake, Tamil Nadu, India. </em></p></div>

scholarly journals Morphometric Relationships in the Blue Swimming Crabs, (Portunus pelagicus) (Linnaeus, 1758) from the Palk Bay, Sri Lanka

2021 ◽  
pp. 29-38
Author(s):  
S. S. K. Haputhantri ◽  
S. J. W. W. M. M. P. Weerasekera ◽  
K. H. K. Bandaranayake
Keyword(s):  
Sri Lanka ◽  
Carapace Width ◽  
Swimming Crab ◽  
Allometric Growth ◽  
Movable Part ◽  
Portunus Pelagicus ◽  
Mouth Width ◽  
Biological Sampling ◽  
Palk Bay ◽  
Swimming Crabs

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.

Biologi Rajungan Portunus pelagicus Linnaeus, 1758 (Crustacea: Portunidae) Ditinjau Dari Aspek Distribusi Ukuran Dan Parameter Pertumbuhan Di Perairan Rembang, Jawa Tengah

2019 ◽  
Vol 8 (4) ◽  
pp. 402-408
Author(s):  
Nathanael Ganang Anindityo Wibowo ◽  
Chrisna Adhi Suryono ◽  
Ibnu Pratikto
Keyword(s):  
Size Structure ◽  
Carapace Width ◽  
Growth Parameter ◽  
Survey Method ◽  
Average Weight ◽  
Swimming Crab ◽  
Female Crab ◽  
Potential Yield ◽  
Portunus Pelagicus ◽  
Male Crab

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.

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