Population dynamics of Parapenaeus longirostris (Decapoda: Penaeidae) (Lucas, 1846), in Central Algerian waters (South-Western of Mediterranean Sea)

The deep-water rose shrimp, Parapenaeus longirostris (Lucas, 1846), has an important economic value in the Algerian market. This work aimed to fill the knowledge gap on the species through the study of growth, mortality, and exploitation rate. The samples of P.longirostris were collected monthly in the Bou-Ismail Bay from 2016 to 2018. The carapace length (CL) of the females and males ranged from 15 to 43 mm and 14 to 38 mm with averages of 28.99±4.76 mm and 25.82±3.92, respectively. The species shows a sexual size dimorphism. The CL and total weight relationship established that growth in both sexes was negatively allometric. The Von Bertalanffy Growth Function parameters for females and males were CL∞=48.80 mm, K=0.60 year-1, and CL∞=41.40 mm, K=0.62 year-1, respectively. The instantaneous rates of total mortalities (Z) were 2.66 year-1 for females and 2.03 year-1 for males. The exploitation rates were 0.66 and 0.49 for females and males, respectively. The length at first capture for males and females is equal to 16.30 mm, 17.14 mm, respectively. The result indicates a beginning of the overfishing situation for P. longirostris. Thus, it encourages undertaking stock assessment studies in the area.