Seasonal variability of oceanographic conditions off NW Galician waters influencing the early life trophic ecology of European hake Merluccius merluccius by stable isotope analysis
Authors
Uriarte-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)Date
2014-09-02Type
conference posterKeywords
Trophic ecologyoceanography
hake
stable isotopes
M. merluccius
Abstract
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 ...