How does the northern Mediterranean population of Helicolenus dactylopterus dactylopterus resist fishing pressure?

The Mediterranean population of bluemouth, Helicolenus dactylopterus dactylopterus (Pisces: Scorpaenidae), is analysed based on 1253 bottom trawls carried out during spring research cruises (MEDITS) along the Iberian Mediterranean coast, from 1994 to 2004. Most individuals were caught at depths of between 201 and 500 m. Both sexes were equally represented at a mesoscale in the entire study area and males attained a larger size than females. A latitudinal and bathymetrical distribution of the bluemouth population, previously observed by some authors, was confirmed. From the south Mediterranean to the north, clear decreases in density, mean total length, biomass value, density indexes and recruitment percentages were observed. The inter-annual oscillation in density indexes and biomass was also estimated. After analysing the structure of the population along the entire western coast, a possible northward dispersal movement of young specimens from the Alboran Sea is discussed to explain why, despite the fishing pressure in the northern sector, the biomass value remains relatively stable.