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vol.30 número1  suppl.SympEl Niño and Occurrence of Coastal Pelagic Fishes Outside the 200-Mile Zone of Peru in 1979-1991Spatial and Temporal Patterns of Shrimp Production in the Gulf of Guayaquil 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/S0717-71782002030100084 

Interactions Between Distribution and
Concentration of Main Pelagic
Resources in Peruvian Waters during
1983 - 2001

Miguel Ñiquen C., Marilu Bouchon C.

Instituto del Mar del Peru (IMARPE), P.O. Box 22 -
Callao, Peru, E-mail: mniquen@imarpe.gob.pe

Pelagic resources in Peruvian waters are very abundant and widely distributed. The main pelagic species are anchovy (Engraulis ringens), sardine (Sardinops sagax), jack mackerel (Trachurus picturatus murphyi) and horse mackerel (Scomber japonicus). The pelagic fishery in Peru increased after El Niño 1982-83, mainly by anchovy, with 9 million tons in 1994 (Fig. 1). This fishery contributes 96% of landings at national level, making Peru the second largest fisheries country in the world.


Fig. 1 Pelagic resource landings at Peru between 1950 and 2001

According to previous studies it is well known that there is high variability in distribution of main pelagic resources in Peru. The temporal changes mainly affect two species: anchovy and sardine, which alternated in dominance at the beginning and end of the 90´s decade. Using data from surveys of stock assesment of pelagic resources and pelagic fishery monitoring, from 1983 to 2001, we analyzed the distribution changes of the main pelagic resources, coincidental with development of El Niño and La Niña events.

The results indicate important interactions between spatial distribution and concentration of resources. In most cases, anchovy and sardine have a strong trend to take a distribution more to north of Peru when there is a La Niña event, with cold waters. Conversely, these species move to the central/south of Peru when there is El Niño event, with warm waters (Fig. 2) - the resources presented an asymmetric distribution toward the south of Peru.


Fig. 2 Anchovy distribution by regions at Peru during 1983 - 2001

According to the magnitude of the event the movement will be stronger, for example with the extraordinary El Niño in 1983, anchovy and sardine went beyond south Peru, while in the moderate El Niño event of 1987, they went to central/south of Peru.

Jack mackerel shows important changes. In cold periods, they have a larger distribution in south and central Peru, and are probably moving north: it was observed in 1996 and 2001 (cold years) that they moved from south Peru to central Peru (Fig.3). There are also biological differences: species composition in the north is mixed with sardine and horse mackerel but in central-south Peru it is dominated by jack mackerel; in size structure, the mean length in the north exceeds 30 cm, while in central-south it is lower than 30 cm. Fisheries are also affected, because industrial fleets have to carry two kinds of net, one for anchovy and young sardine, and another for adult sardine, jack mackerel and horse mackerel.


Fig. 3 Distribution and concentration of jack mackerel on the Peruvian coast during 2001

It is important to highlight the dynamics of Anchoa nasus and Vinciguerria pacifici biomass, which increases and moves from the north and the west during El Niño, while during La Niña events munida (Pleuroncodes sp.), which normally inhabits north Chile, increases and moves to south Peru.

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