Trophic position of Argentine anchovy (Engraulis anchoita) larvae through the analysis of stable isotopes

DO SOUTO, M.; CAPITANIO, F.; GALVÁN, D.; MACCHI, G. J.; DIAZ, M. V.

Connecticut

Conferencia; 44 Larval Fish Conference; 2021

University of Connecticut

Engraulis anchoita larvae have been typified by the literature as exclusively zooplanktophagous. However, some other planktonic components could have been overlooked in the gut content studies. Here we carried out an exploratory analysis of E. anchoita larvae trophic position through a nitrogen and carbon stable isotopes determination at a fixed sampling station in the Argentine sea (38°28' S, 57°41' W), from 2016 to 2018. Mean δ15N and δ13C values indicated that anchovy larvae in all developmental stages overlapped trophic level with chaetognaths, therefore interacting as carnivorous competitors. When analyzing the surveys carried out in autumn separately, where larger larvae occurred, larval trophic levels positioned between the ones of copepods and chaetognaths, corresponding to an omnivorous habit. Due to the small standard length of the larvae collected in summer, winter, and spring, a maternal influence on the isotopic signature cannot be ruled out.