Some biological aspects of Penaeus semisulcatus (Decapoda, Penaeidae) in the Iraqi marine waters

The study explored the fishery, growth, and reproductive biology of the green tiger shrimp, Penaeus semisulcatus, in Iraqi marine waters of the northwest Arabian Gulf from November 2022 to October 2023. Monthly shrimp landings varied significantly, ranging from a low of 57 tons in December 2022 to a high of 407 tons in September 2023, totaling 3,515 tons over the entire year. During this period, 2,394 specimens of P. semisulcatus were sampled, measuring between 10.0 and 25.0 cm in length. The length-weight relationship revealed that male P. semisulcatus exhibited isometric growth, while females showed positive allometric growth. The average condition factor for males was 1.01 ± 0.061, while females had an average of 1.03 ± 0.090, indicating good health for both sexes. The species' growth model was represented by the formula Lt= 28.7 (1-exp(-0.45(t+0.326))). The overall sex ratio was found to be 1:1.06 (male to female). The length at which 50% of the population reaches maturity (L_m50) was determined to be 8.4 cm. The gonado-somatic index (GSI) values for females varied from 2.11% in October to 8.95% in March. These results can contribute to providing information for species management in the study region.