Alimentación de la anchoveta (Engraulis ringens) en el norte de Chile(18°25’-25°40’S) en diciembre de 2010

Abstract

Engraulis ringens diet, in order to determine possible differences in their feeding behavior by size and latitudinal gradient is analyzed. The samples were obtained between 18º25’S and 24º40’S, during the hydroacoustic recruitment assessment cruise conducted between 1 and 20 December 2010. The analysis included the determination of the diet composition in a total of 294 stomachs from 18 sampling stations and distributed in three size classes (pre-recruits, recruits and adults) the were determinate. The diet was described by numerical method, frequency of occurrence and relative importance index, plus dietary similarity in size and latitude and trophic specialization. E. ringens showed a wide trophic spectrum, both phytoplankton and zooplankton prey with a high prevalence of phytoplankton on zooplankton, over 2.5 orders of magnitude in size and latitude range. The components of relative importance in the diet were diatoms of the genus Rhizosolenia and Chaetoceros and Copepoda in the zooplankton. The analysis of intraspecific trophic similarity showed a high overlap between size groups, forming a “trophic unit”. While the latitudinal analysis revealed a high trophic overlap with a tendency to form two "trophic units", but without a definite pattern. The results confirm the nature of a generalist and E. ringens in opportunistic predator of E. ringens in northern Chile during the period analyzed.