Assessing the Population Dynamics and Stock Status of the Orange Mud Crab Scylla olivacea (Herbst, 1796) in Two Oceanic Coasts of Thailand
摘要
This research aimed to investigate the population parameters (viz., structure, growth, mortality, recruitment pattern, and exploitation level) of Scylla olivacea mud crab species from two oceanic regions of Thailand (Pacific and Indian Oceans) from June 2022 to May 2023. This study considered body weight (BW) and frequency of carapace width (CW) data, and FiSAT-II software was utilized for major analysis. The carapace width-body weight relationship (CWR) revealed positive allometric growth (b > 3) in males, whereas negative allometric growth (b < 3) was exhibited in females of S. olivacea from both oceanic sites. The estimated asymptotic carapace width (CW∞) and growth coefficient (K) varied between sexes and locations as Pacific Ocean (male/female = 144.38 mm/139.13 mm, and 0.55 year−1/0.33 year−1) and Indian Ocean (male/female = 133.88 mm/139.13 mm, and 1.1 year−1/0.65 year−1). Mortality (natural mortality = M, fishing mortality = F) and exploitation levels (E) indicated overexploitation for both sexes in the Indian Ocean (male: 1.29 year−1, 2.86 year−1, and 0.69 respectively; female: 0.90 year−1, 1.09 year−1 and 0.55) and males in the Pacific Ocean (0.80 year−1, 1.50 year−1 and 0.65), whereas Pacific Ocean females (0.58 year−1, 0.27 year−1, and 0.32) were under-exploited. The major recruitment peaks for males occurred from February to April (Pacific) and August to October (Indian), while females exhibited recruitment peaks from December to March in both oceans. These findings offer critical insights into off-season regulation, catch size limits, gear selection, juvenile and ovigerous crab protection for sustainable S. olivacea management in Thailand.