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vol.30 número1  suppl.SympImpacts of El Niño Events on the Coastal Benthos of the Eastern Pacific Upwelling SystemsEffects of La Niña 98-2000 on the Population Structure of Emerita analoga, Lambayeque, Perú índice de autoresíndice de materiabúsqueda de artículos
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Investigaciones marinas

versión On-line ISSN 0717-7178

Investig. mar. v.30 n.1 supl.Symp Valparaíso ago. 2002

http://dx.doi.org/10.4067/S0717-71782002030100038 

Effects of El Niño 1997-1998 on
Commercial Marine Invertebrates of
the Peruvian Coast

Silvia Aguilar, Cecilia Roque,
Carmen Yamashiro, Luis Mariátegui

Instituto del Mar del Perú (IMARPE), Apartado 22,
Callao, Perú, E-mail: deim@imarpe.gob.pe

Introduction

The extraction of marine invertebrates constitutes an important part of the Peruvian fishery, conducted entirely by the artisanal fishermen, basically because of its high accessibility and coastal distribution.

Most of these resources are sessile or of low mobility and are very vulnerable to marine and atmospheric changes, such as those appearing during El Niño events. This determines changes in distribution, concentration and behaviour of these resources.

Some biological, fishery and population aspects of the main marine invertebrates of commercial importance along the Peruvian coast are analyzed, with the purpose of determining the effect of the Niño 1997-98.

Results

An increase was observed in the population levels and landings of the scallop Argopecten purpuratus during 1998, with very high stocks of seeds in the natural banks along the Peruvian coast. At the same time an increase in fishing effort was observed, which determined a fast decline in populations during 1999. Landings of the snail Thais chocolata increased during 1997, since the resource was concentrated in coastal areas for reproductive purposes, becoming more vulnerable to the artisan fleet. In relation with conch (Concholepas concholepas), clams (Gari solida, Semele spp), "macha" (Mesodesma donacium), red urchin (Loxechinus albus), patagonian squid (Loligo gahi) and jumbo flying squid (Dosidicus gigas), these resources showed low availability and abundance during the Niño 1997-98, whereas in the case of the octopus (Octopus mimus), its landings and availability were increased (Fig. 1).


The reproductive cycles of most species were affected by the Niño 1997-98, which increased the spawning season of scallop, snails and mussels (Fig. 2). This produced important recruitments in the different areas along the coast; however, the increase in fishing pressure on these resources affected a great part of the young population, catching smaller individuals below the minimum size.


Unlike during El Niño 1982-83, mussel populations (Aulacomya ater) were not severely affected, showing only slight fluctuations in their landings during 1998 and 1999.

The climatic conditions during 1997-98 were favourable for the distribution and abundance of some marine invertebrates in the Peruvian coast, such as scallops, octopus and snails, but the positive impacts did not reach the levels observed during the Niño 1982-83 because of the early increase in fishing effort.

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