Feeding Interrelationships and Comparative Morphology of Two Young Sciaenids Co-occurring in South-western Atlantic Waters

Abstract

Diet and morphology of the sciaenids striped weakfish, Cynoscion guatucupa, and whitemouth croaker, Micropogonias furnieri, from Bahía Blanca estuary (South America) were studied and compared between March 2000-February 2001. Significant differences in mouth morphometric parameters between striped weakfish and whitemouth croaker were found. Premaxila + maxila length, dentary length, and mouth gape were always larger in the former than in the latter. However, analyses of variance (ANOVA) indicated no differences in the mean maximum size of prey consumed by both species. Schoener's dietary overlap was generally moderate between the three ontogenetic trophic groups of striped weakfish and whitemouth croaker. High dietary overlap was observed in winter and summer, when both species prey heavily on Peisos petrunkevitchi and mysid shrimps, respectively. In this study, no evidence of food competition was found between young striped weakfish and whitemouth croaker.