Seasonal variability of oceanographic conditions off NW Galician waters influencing the early life trophic ecology of European hake Merluccius merluccius by stable isotope analysis
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Autor/esUriarte-Ramalho, A. (Amaya); Laiz-Carrión, R. (Raúl); Cabrero, Á. (Águeda); Quintanilla-Hervás, J.M. (José María); Hernández-de-Rojas, A. (Alma); Rodríguez, J.M. (José María); Gago, J. (Jesús); García-García, A. (Alberto)
Palabras claveTrophic ecology, oceanography, hake, stable isotopes, M. merluccius
Stable isotopes of nitrogen (δ15N) and carbón (δ13C) have been used as tracers for analyzing the trophic ecology of European hake larvae collected during the winter and summer of 2012 off NW Galicia. The sampling times correspond to periods of high and low hake spawning activity, respectively. Trophic enrichment was analyzed using as baseline two different plankton size fractions, corresponding to micro- (55-200μm) and mesozooplankton (>200μm). During both seasons, the δ15N signatures of hake larvae showed higher values than the zooplankton fractions. The first survey carried out in late February was characterized by a preceding marked upwelling, low geostrophic velocities in the hydrographic circulation and an intense mixing of the water column. This environmental scenario is hypothesizing that originated a great nutrient availability for primary consumers showed its effect in the low δ15N values observed in plankton and hake larvae. During July, the environmental setting ...