Resumen

MENDO, Jaime  y  WOLFF, Matthias. El Impacto De El Niño Sobre La Producción De Concha De Abanico (Argopecten Purpuratus) En Bahía Independencia, Pisco, Perú. Ecol. apl. [online]. 2003, vol.2, n.1, pp.51-57. ISSN 1726-2216.

Independencia Bay can be considered as one of the most productive invertebrate fishing grounds worldwide. One of the most important exploited species is the scallop (Argopecten purpuratus) with strong catching fluctuations related to El Niño and La Niña events and to inadequate management strategies. During strong warming periods annual landings reach up to 50 000t in an area of about 150 km2 and during cold years they remain around 500 to 1000 t. This study analyses the changes in scallop landings at Independencia Bay observed during the last two decades and discusses the main factors affecting the scallop proliferations during the El Niño events. In this way data on landings, sea surface temperature and those related to growth, reproduction, predation, mean density and oxygen concentration from published and unpublished papers are used. The relationship between annual catches and average water temperature over the preceding reproductive period of the scallop over the past 20 year’s period, showed that scallop production is affected positively only with strong El Niño such as those of 1983 and 1998. Our review showed that the scallop stock proliferation can be traced to the combined effect of (1) an increase in reproductive output through an acceleration of gonad maturation and a higher spawning frequency; (2) a shortening of the larval period and an increase in larval survival; (3) an increase in the individual growth performance; (4) an increase in the juvenile and adult survival through reduction of predator biomass; (5) an increase in carrying capacity of the scallop banks due to elevated oxygen levels. When discussing the factors that contribute to the development of the scallop population during an El Niño event, the fishery must be considered in detail. Since the volume of the catch not only depends on the relative abundance of the species, fishing efforts and strategies were analyzed in order to explain different levels of scallop production during El Niño 1983 and 1998.

Palabras clave : El Niño; landings; management; Argopecten purpuratus; Peru.

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