Resumen de Importancia de la variabilidad climática en las pesquerías y biología de la merluza europea merluccius merluccius (linnaeus, 1758) de la costa noroccidental africana
Fish population and fisheries fluctuations are closely linked to climate dynamics through environmental variability that determines the distribution, migration and abundance of fish. Fishery science were largely focused on the great northern hemisphere fisheries, which some of them fluctuate at decadal time scales and show patterns of synchrony with low frequency signals, as reflected by climatic indices such as the North Atlantic Oscillation (NAO). However, there is scarce information about these patterns at lower latitudes like NW African coast, in spite of this area supports large international fisheries. The aim of this work was to analyze how climate variability described by NAO and the physical environment influences the productivity of European hake abundance, growth and recruitment variability.
In order to understand why it is important to test the climatic hypothesis over European hake stock, I presented the background elements in three main discussion lines. (1) Comparing the biology and population dynamics between European hake of NW Africa and populations from North Atlantic and Mediterranean Sea. (2) the structure and evolution of European hake fisheries in NW Africa, focused on unexplained variability of stock assessment procedures carried out until now. (3) The main climatic and environmental features of NW African coast, emphasizing the potential ecological impact of these features.
It was found a positive relationship between the NAO and hake abundance. NAO explained 35-45% variability of juveniles with 1-year lag and 45-60% of small and large adults with 2-3-years lag. The NAO index is a proper tool to trace the annual growth of European hake, at least during the first three years of life. The growth rate is greater than previous calculus in the area, and it supports the fast growing hypothesis proposed for North Atlantic and Western Mediterranean. The wind stress explained 83% of phytoplankton biomass variability and both of them were positively
