Life strategies of cephalopod paralarvae in a coastal upwelling system (NW Iberian Peninsula): Insights from zooplankton community and spatio-temporal analyses

18 páginas, 6 figuras, 6 tablasThe early life stages of cephalopods - octopods, squids, sepiolids and ommastrephids -, are uncommon in zooplankton samples and little is known about their life strategies. Accordingly, cephalopod paralarvae were examined in the upwelling ecosystem of the Ría de Vigo (NW Spain) at night from 2008 to 2010. Multivariate analyses and generalized linear models (GLMs) were used to explore relationships between cephalopod paralarvae and the zooplankton communities that they inhabited in 2008. In addition, the foraging strategy and prey preferences of Octopus vulgaris paralarvae within these communities were determined. Multivariate and GLM results showed a strong association of cephalopod paralarvae with coastal and frontal zooplankton communities. Octopus paralarvae were shown to be specialist predators with a strong preference for decapod zoeae in each of the communities examined. Using the three years of sampling, GLM analyses of paralarval spatio-temporal variations in relation with the upwelling strength showed a positive relationship with upwelling intensity for O. vulgaris and sepiolids, as well as contrasting temporal, horizontal and vertical distributions for the different paralarvae analysed. Under strong upwelling events, Octopus paralarvae were more abundant in surface waters, whereas the abundance of loliginids and sepiolids was higher in the water column. This vertical behaviour in conjunction with the physical conditions of the Western Iberian Upwelling ecosystem suggests the coexistence of two different life strategies: a coastal strategy displayed by loliginid and sepiolid paralarvae that are retained over the shelf, and an oceanic strategy displayed by O. vulgaris paralarvae that are dispersed far from the shelfThis study was supported by the projects CAIBEX (Spanish Ministry of Innovation and Science CTM2007-66408-C02), LARECO (CTM2011-25929) and FEDER Funds. The first author was supported by a JAE-Predoc fellowship during the sampling, and a ‘Fundacion Barrie de la Maza’ postdoctoral fellowship and RFA funds (La Trobe University, Melbourne) during the writing of the manuscript. J.O. acknowledges the support by a ‘Junta para la Ampliacion de Estudios’ Fellowship (JAE-Doc programme 2011) from the CSIC and ESFPeer reviewe