The effect of physical and biological variables upon condition of Merluccius hubbsi (age-0+) of the northern stock (argentine shelf, SW Atlantic Ocean)

TEMPERONI, B.; LUZ CLARA, M.; BERGHOFF, C.; DERISIO, C.; MASSA, A.E.

JOURNAL OF MARINE SYSTEMS

ELSEVIER SCIENCE BV

Año: 2021 vol. 224

0924-7963

Argentine hake Merluccius hubbsi is one of the most important fishery resources in the Argentinean ContinentalShelf (ACS; SW Atlantic Ocean). In the last decades, the Northern stock (34◦30′ -41◦S) has supported a drasticbiomass decreasing due to overexploitation. Since the strength of a year class is highly influenced by the survivalof age-0+ individuals, studies on their nutritional condition are essential. Age-0+ northern hake nurse in a highlycomplex oceanographic and ecological system, where environmentally-driven changes upon their physiologicalstatus are expected. Hence, several condition (relative condition factor, hepatosomatic index, liver lipid content)and feeding (prey intake) indices were combined with physical (temperature, salinity) and biological (chlorophyll-a concentration, prey abundance) variables to determine spatial variations in age-0+ hake nutritionalstatus. Better conditioned individuals inhabited areas of the study region where chlorophyll-a concentration andzooplanktonic prey abundance exhibited their maximum. A bottom-up control of age-0+ hake physiologicalstatus is suggested, mediated by the consumption of the herbivorous euphausiid Euphausia lucens, which was thepreferred prey. These lipid-rich prey would be beneficial with respect to other available options in the environment,such as hyperid amphipods. Results complement previous observations upon individuals of the Patagonianstock, and provide a thorough insight into age-0+ Northern hake nutritional status, significantlycontributing to M. hubbsi recruitment studies and management in the ACS.