Trophic ecology of the White Croaker (Micropogonias furnieri desmarest, 1823) and Rough Scad (Trachurus Lathami Nichols, 1920) larvae in the Río de la Plata Estuary

Abstract

This study describes the feeding ecology of white croaker (Micropogonias furnieri) and rough scad (Trachurus lathami) larvae in the Río de la Plata Estuary (RPE) during a breeding season. The working hypotheses were that the coexistence of the species under study is favored by spatial segregation and divergence in mouth gape size, which mirrors their diet composition and trophic niche breadth (TNBs), based on prey size. Micropogonias furnieri was more abundant at the innermost stations, while T. lathami was most abundant at outermost stations of the estuary. However, their abundances were uncorrelated to environmental salinity and temperature. Micropogonias furnieri and T. lathami larvae showed differences in their gape growth patterns and in the type of preys ingested, which resulted in low dietary overlap. This did lead to differences in the TNBS and supported the prediction of the trophic differentiation hypothesis and could be interpreted as a mechanism to minimize food competition in the RPE ecosystem.