Variations in the age composition of catch of anchovy (Engraulis mordax) and alternatives for the management of the resource

Abstract

RESUMENSe analiza la estructura de la población de anchoveta antes de la perturbación causada por el fenómeno de "El Niño" durante 1982-1983. Se presentan los resultados del procesamiento de 20,205 datos de edad provenientes de muestreos biológicos de la captura comercial en Baja California durante el período [1978][1979][1980][1981][1982]. Se identifican las clases anuales responsables de las capturas de 1979-1981. Se establece que el grupo de un año de edad ha sido el principal generador de captura. Se describe la variabilidad de la composición por edades y se observa una situación de pesca de individuos jóvenes. Se sugiere que se limite la captura de peces menores de un año de edad, con el objeto de permitir una mayor incorporación de biomasa por efecto del proceso de crecimiento. Se discute sobre los conceptos de clase anual y reclutamiento y su relaci6n con procesos como vulnerabilidad y comportamiento social. ABSTRACTThe structure of the northem anchovy population before the disturbance caused by "El Niño" in 1982-1983 is analyzed. 20,205 age data originated from biological sampling of the commercial catches in Baja California throughout the 19781982 period were processed, and the results are presented here. The year classes responsible for the catch in 1979-1981 are identified. It is established that the one year old group has been the main catch generator. The age composition variability is described and a situation of capture of young individuals is obsemed. It is sugested to limit the capture of individuals younger than one year with the purpose of allowing a higher biomass incotporation by the growth process. The year class and recruitment concepts as well as their relation to vulnerability and social behavior processes are discussed. INTRODUCCION INTRODUCI'IONLa anchoveta (Engnzulis mordar morThe northem anchovy (Engmulis mordux Girard, 1856) es un organismo de especial dar mottiux Girard, 1856) is an organism of a significado en la cadena alimentaria del ecosisspecial importance in the food chain of the tema costero. En esta especie se concentra una coastal ecosystem. A great proportion of the gran proporción del flujo de energía y con ello energy flux is concentrated in this species, 73

Validation of daily microincrement deposition in otoliths of juvenile and adult Peruvian anchovy Engraulis ringens

“…To date, the information gathered on age structure for anchovy species associated with highly productive systems has shown that some anchovies (e.g. genus Engraulis) appear to be relatively short-lived, with a maximum life span ranging from 4 to 5 years and a maximum asymptotic total length (L T ) ranging from 16 to 19 cm (Hayasi & Kondo, 1957;Mais, 1981;Vidal-Talamantes, 1991;Waldron, 1992;Basilone, et al, 2000). Recent studies using otolith microstructure analysis have reported fast growth patterns at the daily level for some anchovies and for other small pelagic fishes as well (La Mesa et al, 2009;Aldanondo et al, 2011).…”