Volumen 43 - Número 1: 11-119 | 2008
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Method to obtain abundance indices in the population of Farfantepenaeus californiensis (Holmes, 1900) from the Gulf of Tehuantepec, Oaxaca, Mexico

Pedro Cervantes-Hernández^1,2*

¹Instituto de Recursos, Universidad del Mar, Sede Puerto Ángel, A. P. 47., C. P. 70902, Puerto Ángel, Oaxaca, México

²Alumno adscrito al posgrado del Instituto de Ciencias del Mar y Limnología, UNAM, México

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A method to model the annual abundance variation of the Farfantepenaeus californiensis (Holmes, 1900) from the Gulf of Tehuantepec, Oaxaca, Mexico is proposed. Principal components analysis (PCA) was used to obtain two population indices: the abundance of recruits, or FR index, and the abundance of spawners, or DR index. The age group of four months was used to calculate the FR index and the age groups from six to 11 months were used to calculate the DR index. The analysis of the fishery mortality rate (F) indicated that shrimp between 12 (F= 0.88 monthly) and 16 months (F= 1.66 monthly) were overfished, and that 3 months old shrimp were observed partially recruited to the fishery (F= 0.02 monthly); for this reason, PCA did not show a significant factor loading in any of the indices. The age groups selected by PCA in each calculated population index were observed underfished in the natural population so that these age groups were considered very important to maintain the continuity of the fishery between 1989 and 1998. Based on the annual abundance variation of FR and DR obtained by the virtual population analysis (VPA), from July to August/September, the abundance of recruits was higher than the spawners, while from October to January, the abundance of spawners was higher than the recruits.

Key words: Brown shrimp, recruits, spawners, annual variation, Mexican Pacific