Growth, mortality and stock assessment of <i>Metapenaeus affinis</i> (Decapoda, Penaeidae) from Iraqi waters

Jinga shrimp (Metapenaeus affinis) is one of the most productive shrimp fisheries in Iraqi waters. The study aimed to evaluate the growth, mortality, recruitment, yield-per-recruit, and virtual population analysis (VPA) of the M. affinis shrimp in these Iraqi waters. Samples were collected from the nursery grounds of the species in east Hammar marsh and the fishing grounds in Iraqi marine waters between November 2022 to October 2023. A total of 8021 M. affinis ranged from 2.0 to 15.6 cm TL (0.6-6.0 cm CL) were examined. The length-weight relationship exhibited a positive allometric growth pattern. Total length-frequency data for combined sexes was analyzed using the FiSAT II software. The asymptotic length, growth coefficient and growth performance index were 16.3 cm, 0.92 and 2.388, respectively. Total, natural and fishing mortalities were 3.69, 1.82 and 1.87, respectively. The current exploitation rate (Ecur) was 0.51. Length at first capture (Lc50) was higher than at first maturity length (Lm50). Recruitment continued throughout the year, with one major peak in April. The analysis of relative yield per recruit and relative biomass per recruit indicated that the Ecur of the stock was equal to its optimal level (E0.1= 0.520) and below its maximum sustainable yield (Emax= 0.628). To effectively manage the M. affinis stock, it is essential to adjust the mesh size so that the total length of the species at first capture must not be less than the length at first maturity. Consequently, it may have a chance to breed, and the nursery grounds should be protected from illegal fishing.