We analyzed the influence of some abiotic variables in the biomass distribution of these species using survey data collected over four years (2006-2009) in the Catalano-Levantine coast of Spain. The preliminary results show that variables such as time (year) and latitude feebly affect the biomass distribution of these species. Depth, by itself, is not as significant as believed, masking the influence of other variables. M. barbatus biomass distribution seems to be especially influenced by salinity and, to a lesser extent, by temperature, while only temperature seems to have a significant effect on the M. surmuletus biomass distribution. These results are consistent with the bathymetric distribution of both species, with M. barbatus showing affinity for low salinity waters and M. surmuletus for warmer waters, which may contribute to the segregation of the species.