Variación de los hábitos tróficos en nueve especies de peces de la Laguna Garzón (Uruguay)

Abstract

Trophic role including nine fish species from a coastal lagoon in Uruguay (Laguna Garzón) was assessed using carbon and nitrogen stable isotope measurements. To this end, samples of food sources and fishes were collected in May 2017 for isotopic analysis. Fishes were collected by deploying a net of 10 and 15 cm (200 m long) for 12 hs. The results indicated an isotopic variation within the fish species examined thus suggesting different trophic habits. The highest trophic positions (TP) were observed for the anchovy Lycengraulisgrossidens (TP = 3,8), the bluewing searobin Prionotus punctatus (TP = 3,4), the whitemouth croaker Micropogonias furnieri (3,4), and dog-tooth characid Oligosarcus jenynsii (TP = 3,0). Model calculations showed that the main prey for the fish species in Garzón derived from benthic (e.g. M. furnieri, Mugil liza) and pelagic environment (Odontesthes argentinensis). Therefore, benthic fauna together with sedimentary carbon sources support this fish assemblage in Laguna Garzón.