The teleost fishes Serranus cabrilla, Trachinus draco, Chelidonichthys lastoviza and Chelidonichthys cuculus are important by-catch species in the bottom trawl fishery developed along the continental shelf of the Balearic Islands (Western Mediterranean). They constitute an important fraction of the mixed fish category commercialized as “Morralla”, with annual landings averaging 110 tons in the last decade. The main biological parameters and a demographic analysis of these species are presented in this study. We have estimated the length-weight relationships, the growth parameters of the Von Bertalanffy equation, the spawning season, the length of first maturity, and the natural mortality of these species, as well as their bathymetric distribution and abundance. Samples and data used come from the monthly monitoring of the bottom trawl fishery (2008-2010) and the annual MEDITS survey in the study area (2001-2011), developed within the Data Collection Framework of the European Commission. Based on a steady state assumption, three years pseudo-cohorts (2008-2010) were created for each species by using catch data and fish length frequencies obtained by observers on board, and the annual official landings. Virtual Population Analysis (VPA) and Yield per Recruit models were carried out on these pseudo-cohorts using the estimated biological parameters in order to assess the exploitation level of the species. The state of the populations were also analyzed using fishery-independent indicators (based on MEDITS data) within the context of the Marine Strategy Framework Directive such as the range and pattern of distribution, the Conservation Status of Fish, and the evolution of abundance and biomass of the populations. Our results can contribute to the improvement of the biological knowledge of fish species poorly studied in the western Mediterranean and the assessment and management of the bottom trawl fishery in the area. [...]

XVII Simposio Ibérico de Estudios de Biología Marina (SIEBM), 11-14 September 2012, Donostia-San Sebastián

Peer reviewed