Relationships between Octopus vulgaris landings and environmental factors in the northern Alboran Sea (Southwestern Mediterranean)

The relationships between environmental factors and fluctuations in Octopus vulgaris landings in the northern Alboran Sea are studied from 1987 to 2007. Landings during this period show both a long term decrease and a strong inter-annual variability. An exploratory phase revealed that local coastal temperatures and those averaged for the whole Alboran Sea during the previous year were the main factors controlling such variability. Warm anomalies have a detrimental effect on the octopus landings on the following year and this suggests that the decreasing trend in octopus landings could be partially linked to the long term warming observed in the Western Mediterranean. It is not yet clear which are the specific mechanisms linking warm anomalies to landing decrease. Nevertheless some hypotheses are proposed and a statistical model is developed for attempting to predict octopus landings one year ahead.