Population dynamic and reproduction of Artemesia Longinaris (Decapoda, Penaeidae) in Rio De Janeiro State, South-Eastern Brazil

• Published in: Boletim do Instituto de Pesca Vol. 34; no. 1; pp. 89 - 98
• Main Authors: Semensato, XEG, Di Benedetto, APM
• Format: Journal Article
• Language: English; Portuguese
• Published: 01.01.2008
• Subjects: Artemesia longinaris; Decapoda; Penaeidae; Brazil, Rio de Janeiro
• ISSN: 0046-9939

During 2004, the length-frequency data of Artemesin longinaris (Decapoda, Penaeidae) were analyzed in Rio de Janeiro State, south-eastern Brazil, to provide information on the growth, reproduction and mortality. Monthly samples were collected from January to December 2004 during the local shrimp fishery operations. The specimens were sexed, checked for maturity and their carapace length (CL) and wet weight were measured. The size at first maturity (CL sub(50%)) and the breeding period was also verified. The FiSAT II program package routines were used to identify the Von Bertalanffy growth function (VBGF) (CL sub(1) = CL, (1 - exp - K (t - t sub(0) that best fits the size class, to estimate the mortality rates and the size at first capture (CLC sub(50)), and to predict the relative yield-per-recruit (Y'/R). The mean CL of immature and mature specimens was 10 and 13 mm for males, and 14 and 17 mm for females. The carapace length-weight relationship for both sexes indicated a strong allometry, where females were greater than males. The VBGF parameters differ between sexes: CL, = 18.9 mm and K = 0.69 year super(-1) (males) and CL sub(t) = 28.4 mm and K = 0.58 year super(-1) (females). The CL sub(50%) (12.5 mm for males and 16.4 mm for females) and the CLC sub(50%) (9.6 mm for males and 10.7 mm for females) indicate that the shrimps are usually recruited to the fisheries before producing new recruits. Breeding occur year-round, but ripe females were most abundant in May (autumn) and September (late winter-early spring). The total mortality was 2.88 for males and 1.88 for females and these differences could be related to the natural mortality and distinct growth rates. The Y'/R analysis indicated that the actual exploration rate in the region is still lower than the predicted maximum values. The local actions, the community-based management and the educational campaigns could be more suitable to this shrimp population sustainability. They can include alternative management related to the trawl-net fishery, changes in the mesh size selection and even temporal change in the official closure of this fishery. The present results have to be considered with caution to management proposes and the continuous and long term monitoring is still require to better understand the A. longinaris population dynamic and its fishery scenario in the study region.