Biologi Rajungan Ditinjau dari Aspek Morfometrik dan Sex Ratio yang Didaratkan di Perairan Rembang

ABSTRAK : Rajungan (Portunus pelagicus) memiliki nilai ekonomi tinggi, berbanding lurus dengan penangkapan yang meningkat. Tingkat pemanfaatan yang tidak konservatif akan mempengaruhi  ukuran dan kondisi rajungan di suatu populasi, serta stok rajungan di suatu perairan. Penelitian bertujuan untuk mengetahui kajian konservasi rajungan (Portunus pelagicus) berdasarkan morfometri dan sex ratio yang didaratkan oleh nelayan  di Perairan Desa Gegunung Wetan, Kecamatan Rembang, Kabupaten Rembang. Metode yang digunakan dalam penelitian bersifat deskriptif. Pengamatan rajungan dilakukan pada salah satu pengepul di Desa. Rajungan di amati berdasarkan morfometri dan sex rasio selama 30 hari. Hasil Informasi dapat dijadikan pedoman dalam menentukan kebijakan mengenai pengelolaan perikanan rajungan yang berkelanjutan dan bersifat konservatif. Hasil dari penelitian diketahui bahwa kelimpahan rajungan jantan sebesar 46% (1379 ekor) rajungan betina 56% (1621 ekor) dari 3000 ekor sampel rajungan. Rasio perbandingan jantan dan betina 1:1,18. Berdasarkan distribusi ukuran lebar karapas rajungan di perairan Rembang adalah berkisar anatara 72–167  mm dan distribusi berat sebesar 40–303 gram. Distribusi tingkat kematangan gonad pada perairan Rembang adalah 608 ekor pada TKG 1; 658 ekor pada TKG 2; dan 355 pada TKG 3. Data menunjukan bahwa pola pertumbuhan rajungan yang ada di perairan Rembang adalah allometrik negatif  baik rajungan jantan maupun rajungan betina. Abstract: Blue swimming crab (Portunus pelagicus) has a high economic value, directly proportional to the increased catch. The level of non-conservation utilization will affect the size and condition of the blue swimming crab in a population, as well as the blue swimming crab stock in a waters. This study is aimed to determine the blue swimming crab conservation study (Portunus pelagicus) based on morphometry and sex ratio brought by fishermen in the waters of Gegunung Wetan Village, Rembang District, Rembang Regency. The method used in this study is descriptive. 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 sex ratio for 30 days. Informative results can be used as a guide in determining policies regarding sustainable and conservation management of blue swimming crab fisheries. The results of the study revealed that the abundance of male blue swimming crab was 46% (1379 male blue swimming crab) and the abundance of the female blue swimming crab was 56%  (1621 female blue swimming crab) of 3000 blue swimming crab samples. The ratio of male and female  is 1:1.18. Based on the size distribution of the width of the blue swimming crab carapace in the waters of Getanung Wetan it ranges from 72-167 mm and the distribution of weight is 40-303 grams. 13.8% (413 blue swimming crab) sized≤10 cm and 86.2% (2587 blue swimming crab) sized ≥10 cm. The distribution of gonad maturity level in the waters of Gegunung Wetan is 608 female blue swimming crab at TKG 1; 658 female blue swimming crab at TKG 2; and 355 female blue swimming crab at TKG 3. There were 355 female blue swimming crab (22%) of the total female blue swimming crab laying eggs. The data showed that the blue swimming crab growth pattern in Gegunung Wetan waters was negative allometric both male and female blue swimming crab.