Possible predation by the striped weakfish Cynoscion guatucupa on estuary-associated fishes in an Argentinian coastal lagoon

BLASINA, G.E.; LOPEZ CAZORLA, A.; DÍAZ DE ASTARLOA, J. M.

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: Londres; Año: 2015

1745-1000

Cynoscion guatucupa is one of the most important coastal fishery resources of 28 Argentina and Uruguay with both juveniles and adults being recorded in Mar Chiquita 29 coastal lagoon, a shallow water estuarine lagoon in Argentina. Cynoscion guatucupa 30 enters and exits the lagoon following tidal cycles, with residence time within the lagoon 31 lasting only for the duration of a tidal cycle. The main objective of this study was to 32 determine the diet composition of Cynoscion guatucupa captured in the lagoon, and to 33 determine if different size classes of this species differentially utilize available food 34 resources during their residency within the coastal lagoon. The diet of 511 specimens of 35 C. guatucupa was analyzed. The most important prey item in %IRI was Peisos 36 petrunkevitchi, followed by juvenile teleosts including those of Micropogonias furnieri, 37 Odontesthes argentinensis and Mugil platanus. Cynoscion guatucupa enters the lagoon 38 to feed on a variety of invertebrates as well as juvenile teleost fishes. Diet composition 39 showed ontogenetic changes: smaller individuals predominantly consume crustaceans, 40 and as size increases they begin to prey more on teleosts, with the largest fishes 41 specializing on fish. The present study reinforces the role of estuaries for marine fishes 42 as both feeding grounds, for juveniles and adults and as refuge areas for juveniles. 43 Furthermore, this study also highlights the importance of food habit studies, for 44 understanding the trophic ecology of fishes and estuarine food web dynamics.