Temporal feeding habits of the whitemouth croaker Micropogonias furnieri in a shallow coastal lagoon (southwestern Atlantic Ocean, Uruguay)

Abstract

We analyzed the stomach contents of 2915 individuals of the whitemouth croaker, Micropogonias furnieri, ranging from 15.6 to 42.0 cm total length, collected from a coastal lagoon in Rocha, Uruguay, during 1997–1999. A total of 56% (n = 1646) of individuals were found with content in their stomachs. Six food items were identified and classified as crustaceans (49%), polychaetes (26%), vegetal debris (15%), molluscs, juvenile fishes, and unidentified contents, the latter three representing less than 5% of the total stomach contents. Fishes displayed a higher proportion of stomachs with food between February and August 1998, simultaneous with a low gonadosomatic index and a decrease in water temperature. Crustaceans were the dominant food item from November 1997 to March 1998 and from November to December 1998 (austral summer), whereas polychaetes were predominant from April to October 1998 and from January to February 1999. Availability of polychaetes and their higher frequency of occurrence in the stomachs before the reproductive period could play an important role in the reproduction of the species. Feeding frequency was correlated with length classes. Smaller fishes (<25 cm) preyed on polychaetes and vegetal debris, whereas larger fishes fed mainly on crustaceans and fishes. The temporal feeding habits of M. furnieri in this coastal lagoon showed selective and opportune utilization of prey items according to annual variability in reproductive status and water temperature.