"Linking diet and nutritional condition of young-of-the-year Merluccius hubbsi to zooplanktonic prey quality in the Argentine Sea: insight from stomach content and fatty acid analysis"

TEMPERONI, BRENDA; MASSA, AGUEDA E.; VIÑAS, MARIA DELIA

MARINE BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2015

0025-3162

During the recruitment process of fish, quality and availability of food for larval and juvenile stages can have significant consequences upon their growth, nutritional condition and survival. In the Argentine Sea, young-of-the-year (YOY) juveniles of the Patagonian stock of hake Merluccius hubbsi have their main nursery area in the San Jorge Gulf (SJG, 45º-47ºS, 65º30?W). To gain insight into diet, nutritional condition and prey quality of these juveniles, information about stomach content and biochemical composition -lipid and fatty acids (FA)- obtained during austral summer of 2012 and 2013, was combined. Biochemical tools are used for the first time in the Argentine Sea in the context of fish trophic and condition studies. Stomach analysis evidenced that YOY hake prey upon the macrocrustaceans Euphausia lucens, Themisto gaudichaudii, Munida spp., and Peisos petrunkevitchii. This was validated by a high overlap between predator/prey FA profiles. YOY hake carnivorous behavior was evident from a high 18:1n-9/18:1n-7 ratio, while the presence of FA markers 22:6n-3 and 22:1n-9 suggested a high contribution of dinoflagellates and calanoid copepods to the SJG food web, respectively. Prey items were rich in polyunsaturated FA, particularly 22:6n-3, which might be critical for YOY hake early development. Spatial variations in condition and feeding success suggest that both prey quality and availability -affected by the presence of highly productive tidal fronts- would modulate YOY hake nutritional condition in the nursery area.