Abstract

ORREGO, Henry  and  MENDO, Jaime. Interannual variation in the diet of hake Merluccius gayi peruanus (GUITCHENOT) on the peruvian coast. Ecol. apl. [online]. 2012, vol.11, n.2, pp.103-116. ISSN 1726-2216.

Merluccius gayi is the most important demersal species exploited by the fishery industry in the northern coast of Peru and plays an important ecological function in the ecosystem. In order to know its predatory behavior stomach content of 2836 individuals were analyzed. The individuals were caught on board of industrial trawlers in the north of Peru during 1995 to 1997. The total lengths ranged between 24 and 73 cm and mainly in a range of 34 and 46 cm. The percentage of stomachs with food in different length classes ranged between 39.5 and 100%. Fishes were the largest item in the diet with 87% followed by the mollusks cephalopods with 10.4% and crustaceans with 2.6%. The euphausiids were the most abundant crustacean and among the fishes ingested the hake was the main food item (40.6%) showing a high degree of cannibalism, followed by the Engraulidae (24.1%) clearly dominated by the anchovy. For 1997 the diet showed a wider spectrum. Based on IRI values, the predominant groups in the diet corresponded to Eufausidae, the species Engraulis ringens, Merluccius gayi and P. stephanophrys. According to the total fullness (TFI) showed a positive trend mainly until the end of 1996, however after started to decline. The cluster analysis applied to the stomachs contents sampled in 1995 and 1996 by length classes organized the individuals in 3 groups: of 30-34 cm, 34-50 cm and 50-66 cm. For 1997, the cluster analysis grouped the stomachs of hake into two groups of 30-46 cm and 50-66 cm, which demonstrates the effect of El Niño on the foraging behavior and the adaptation of hake to changes in the food supply.

Keywords : Merluccius gayi peruanus; feeding habits; El Niño; Peru.

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