Evaluating the role of endogenous and environmental features on larval hake nutritional condition

DIAZ, M. V.; DO SOUTO, M.; BETTI, P.; TEMPERONI, B.; SCHIARITI, AGUSTÍN; MACHINANDIARENA, L.; BROWN, D.; MACCHI, G.

FISHERIES OCEANOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 29 p. 584 - 596

1054-6006

Evaluating the nutritional condition of fish larvae is imperative to establish the importanceof starvation, understanding the causes of larval mortality and determiningfavorable zones for growth and survival within nursery areas. We assessed thenutritional condition of Merluccius hubbsi l arvae e mploying R NA/DNA i ndex ( sRD)and its derived index of growth performance (Gpf). Larvae (N = 395) were collectedduring the reproductive peak in 2010 and 2011. Principal Component Analysis andGeneralized Linear Models were used to study the relationship between larval conditionand endogenous factors (size, weight, growth rate, trophic incidence, and carboncontent per stomach) and exogenous variables (temperature, chlorophyll concentration,potential prey availability, ctenophore biomass, and hake larvae density). Theyear of sampling was also considered as a variable. The significant variables in themodel selection were size, temperature, the density of hake larvae, and year. The larvalsize was positively related to the condition while larval density and temperatureshowed a negative relationship with the sRD index. The year was also a significantvariable, with higher larval sRD values in 2010. The negative relationship betweensRD and larval density suggests the existence of mechanisms of density-dependenceoperating upon larval condition. On the other hand, the lower temperatures occurredin stratified waters (with greater availability of food) a fact that might explain the negativerelationship between sRD and temperature. The fitting of the models suggeststhat other explanatory variables might be considered to improve the understandingof the nutritional condition index nature.