Stock Analysis of Shrimp Scad (Alepes djedaba) Fishery from Northern Arabian Sea, Balochistan Coast, Pakistan

Abstract

Alepes djedaba (Forssakal, 1775), is commonly known as yellowtail fish/shrimp scad, belonging to Carangidae family widely spread in tropical waters. A. djedaba is commercially important fish species from northern Arabian Sea, Pakistani waters. Present study was conducted on stock status of shrimp scad A. djedaba fishery from Balochistan coast, Pakistan. The data was collected from March 2019 to February 2020, and a total of 1,027 pairs of length-weight and length-frequency data distribution were measured. Computer software FiSAT package was used to analyze the growth and mortality rate parameters. The length-weight relationship values for male was W= 0.016xb2.906 (R2 = 0.950) and female was W= 0.029xb2.724 (R2 = 0.941). The combined data of both sexes were W= 0.021xb2.830 (R2 = 0.945). The electronic length-frequency analysis (ELEFAN) method was used to estimate the VBGF parameters, which were L∞ = 39.9 cm (FL), K = 1.6 yr-1. However, total mortality (Z) was estimated using a lengthconverted catch curve analysis and found at Z = 5.31 yr-1 with a 95% confidential interval (CI = 4.77- 5.84). Natural mortality was estimated at M = 2.16 yr-1 using an average temperature of sea 26°C in Pakistani waters, though, the fishing rate was obtained by F = Z-M = 3.15 yr-1. Exploitation rate (E) was at E = F / Z = 0.593 yr-1. The length-weight relation values show the isometric growth in nature and similar to previous studies. The mortality and exploitation rate was found higher than previous studies which indicate the high commercial demand of this species from Pakistani waters. The exploitation rate from Pakistani waters is higher than limit point (> 0.5) which indicates that stock of this fishery is in overexploitation state. It may also be recommended that some management measures should be taken to maintain the stock of this fishery at sustainable level for future generation.