Environmental effects on Octopus vulgaris landings in northwest Spanish waters

Abstract

The common octopus (Octopus vulgaris) is the target species of the cephalopod trap fishery in the NW Iberian Peninsula. Landings show wide inter and intra annuals fluctuations. We analyzed the logbook time series of the Spanish trap fishery from 2003 to 2012 to investigate its variability. There is a marked seasonality in the biomass index (catch per unit effort) with the highest value being reached place during the winter season, using generalized additive models (GAMs) we explore the potential effects of several environmental variables on time-series of octopus trap fishery. Results indicate significant effects of sea surface temperature (SST), NAO and the upwelling index on the octopus biomass index