Abstract

GONZALEZ-OCHOA, Oscar A; LOPEZ-MARTINEZ, Juana  and  HERNANDEZ-SAAVEDRA, Norma Yolanda. Population characteristics of spotted rose snapper lutjanus guttatus caught as shrimp bycatch in the gulf of California . INCI [online]. 2009, vol.34, n.11, pp.808-813. ISSN 0378-1844.

There are limited population biology studies of the spotted rose snapper Lutjanus guttatus. Adults of this highly valued commercial species are fished with gillnets and hook-and-line, while juveniles are caught as shrimp bycatch and usually discarded. The effects of this practice have not been studied. As a first step, this study assessed some population parameters of juvenile snapper caught by the Gulf of California shrimp fishery. We looked for early growth stages and determined by the least squares method the weight to standard length relationship as W= 0.000092, SL3.0509. Length frequency distributions were constructed; using the ELEFAN I method, von Bertalanffy growth parameters were found to be L¥= 515mm (standard length) and K= 0.13. Natural mortality (M= 0.35) was estimated from Pauly’s empirical and Ralston equations; and total mortality was calculated by the catch curve equation. The recruitment pattern extended throughout the year, with spring and summer peaks. The sex ratio was 1:1 and the length at capture was 80mm (standard length). With an apparently high fishing mortality levels, it is recommended that abundance and distribution studies be performed to determine the impact of shrimp fishing on this population.

Keywords : Bycatch ; Gulf of California ; Juvenile Fish ; Lutjanus guttatus .