Stock assessment of the green tiger shrimp Penaeus semisulcatus De Haan, 1844 from Northwest Arabian Gulf, Iraq

This study presents the initial stock assessment of the green tiger shrimp, Penaeus semisulcatus De Haan, one of the most productive fisheries in Iraqi marine waters. The growth, mortality, recruitment, yield-per-recruit, and virtual population analysis (VPA) of P. semisulcatus in Iraqi marine waters in the northwest Arabian Gulf were studied from November 2022 to October 2023, to manage and conserve the population of this species. Total length-frequency data of 2,394 specimens of P. semisulcatus were analyzed using the FiSAT II software. The length-weight relationship was W= 0.0044TL3.208, indicating an isometric growth pattern. The asymptotic length (L∞) and growth rate (K) were 28.7 cm and 0.50 respectively. Total, natural and fishing mortalities were 2.81, 1.01 and 1.80, respectively. The current exploitation rate (Ecur) was 0.64. Recruitment continued throughout the year with one major peak in May. Length at first capture Lc50 (15.1 cm) was higher than length at first maturity Lm50 (14.5 cm), indicating that they may be vulnerable to capture by the available fishing gear after they mature. VPA results show that most of the catches of the individuals occurred at mid-lengths of 17-23 cm, and the maximum fishing mortality was at a length of 21 cm. The yield per recruit analysis shows that the current exploitation rate (Ecur) was below the biological target reference points (E0.1 and Emax), indicating that the stock of P. semisulcatus is being exploited rationally. To promote sustainable management, shrimp nursery grounds should identify for protection, and update the law regulating the exploitation and protection of aquatic life to regulate fishing in Iraqi marine waters.