Abstract

ORREGO, Henry  and  MENDO, Jaime. Jack mackerel Trachurus murphyi (Nichols) feeding habits in the north-central peruvian sea. Ecol. apl. [online]. 2015, vol.14, n.2, pp.103-113. ISSN 1726-2216.

Trachurus murphyi is one of the most relevant species in the food chains of the pelagic-oceanic system and represents one of the most important industrial fisheries in the Peruvian coast. In order to know its predatory behavior, stomach contents of 3175 individuals were analyzed. The individuals were caught on board in industrial semi-pelagic trawlers and purse seine vessels in the north and central coast of Peru from 1995 to 1997. Individuals´ total lengths ranged from 22 to 58 cm, the main range being from 26 to 46 cm. Percentage of stomachs with food of different length classes ranged from 42.3 to 100%. Crustaceans were the largest item in the diet with 60.4% followed by fishes with 39.3% and mollusks with only 0.36%. Euphausia. mucronata was the most representative species in the diet with 54.3% followed by a 35.5% of fishes which could not be identified due to decomposition processes. Based on IRI values, the predominant groups in the diet corresponded to the Eufausidae family. Cluster analysis applied to the stomachs contents sampled in 1995 by length classes organized the individuals into 2 groups: <26 a 49.9 cm and 50-53.9 cm. For 1996 it is similar to 1995 and for 1997 a year affected by an El Niño event, cluster analysis grouped the jack mackerel stomachs of into two well defined groups < 26 to 53.9 cm and 54 to >58 cm.

Keywords : Trachurus murphyi; feeding habits; El Niño; Peru.

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