Second Workshop on Atlantic chub mackerel (Scomber colias) (WKCOLIAS2)

The Atlantic chub mackerel Scomber colias has become an increasingly important commercial species in the European Atlantic waters in the last 10–15 years, probably through an expansion process from NW African waters and due to market needs. However, at present there are no assessment or advice requirements. In the WK framework, available information of the species in the West Atlantic waters has been compiled in order to evaluate possible geographical differences and trends, and the feasibility to describe its population structure. Though the Atlantic chub mackerel is not routinely included among the target species in the acoustic surveys performed in the Atlantic Iberian waters and the Mediterranean Sea, a synoptic overview of the species is possible over all its West Atlantic distribution. Moreover, the data available have indicated latitudinal trends, mainly in the landings’ length composition, L50 and the spawning periods. Nevertheless, even if some degree of connectivity likely exists and migrations are occurring between adjacent areas, some subunits could be considered for management purposes. From the assessment models’ trials carried out, the results or reference points obtained for the European fisheries cannot be retained at present. Therefore, continuing collating information from fisheries and biological sampling of the species, obtaining reliable biomass estimations from scientific surveys and identifying management units seem the main priorities to address in future research work and in case of assessment requirements

Distribution of black hakes Merluccius senegalensis and Merluccius polli along the Moroccan Atlantic coast

In the Northwestern coast of Africa three species of hakes overlap. These include European hake Merluccius merluccius (Linnaeus, 1758), Senegalese hake Merluccius senegalensis Cadenat, 1950 and Benguela hake Merluccius polli Cadenat, 1950. The Black hakes M. senegalensis and M. polli have their northern distribution limit in Morocco. In this study, this limit was set to 33.05°N (33° 3' 0" N) for M. senegalensis and 28.28°N (28° 16' 48") for M. polli. The fluctuation in the northern limit of the black hakes distribution could be a result of changes in oceanographic parameters (as the area is affected by the upwelling and considered as a transition zone between a warm and a cold region) or a seasonal migration of the species. A misidentification of species is not excluded. The general trend of the yield’s average decreases with latitude. South of the latitude 25°N M. polli is more abundant in average than M. senegalensis even if the latter could show some high yield spots (up to 155 kg h-1 ). North of the latitude 25°N, the situation is inversed. Black hakes were caught up to about 1000 m depth (1055 m for M. senegalensis, deeper than the ever-reported depth). M. polli showed a deeper distribution than M. senegalensis and was absent from the strata shallower than 300 m. The main concentration of M. polli was between 500 and 700 m where 81% of individuals are caught. The main concentration of M. senegalensis was in the stratum 300-600 m where 77% of individuals are caught. The maximum overlap of the two black hakes species was between 400 and 600 m suggesting a deeper population in the northern zone of the distribution of these species. Although M. senegalensis shows a maximum size (73 cm) greater than M. polli’s maximum size (66 cm), its average size in the study area (44.06 cm) was significantly smaller than M. polli’s average size (48.84 cm). The black hakes are considered as shared resources and need more studies with a regional scope so as to contribute to their management

Identifying management actions that promote sustainable fisheries

Which management actions work best to prevent or halt overfishing and to rebuild depleted populations? A comprehensive evaluation of multiple, co-occurring management actions on the sustainability status of marine populations has been lacking. Here we compiled detailed management histories for 288 assessed fisheries from around the world (accounting for 45% of those with formal stock assessments) and used hierarchical time-series analyses to estimate effects of different management interventions on trends in stock status. Rebuilding plans, applied less commonly than other management measures (implemented at some point historically for 43% of stocks), rapidly lowered fishing pressure towards target levels and emerged as the most important factor enabling overfished populations to recover. Additionally, the ratification of international fishing agreements, and harvest control rules specifying how catch limits should vary with population biomass, helped to reduce overfishing and rebuild biomass. Notably, we found that benefits of management actions are cumulative—as more are implemented, stock status improves and predicted long-term catches increase. Thus, a broad suite of management measures at local, national and international levels appears to be key to sustaining fish populations and food production.Fil: Melnychuk, Michael C.. University of Washington; Estados UnidosFil: Kurota, Hiroyuki. Japan Fisheries Research and Education Agency; JapónFil: Mace, Pamela M.. No especifíca;Fil: Pons, Maite. University of Washington; Estados UnidosFil: Minto, Cóilín. Galway-Mayo Institute of Technology; IrlandaFil: Osio, Giacomo Chato. No especifíca;Fil: Jensen, Olaf P.. Rutgers University; Estados Unidos. University of Wisconsin; Estados UnidosFil: de Moor, Carryn L.. University of Cape Town; SudáfricaFil: Parma, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Richard Little, L.. Csiro Oceans and Atmosphere; AustraliaFil: Hively, Daniel. University of Washington; Estados UnidosFil: Ashbrook, Charmane E.. University of Washington; Estados UnidosFil: Baker, Nicole. University of Washington; Estados UnidosFil: Amoroso, Ricardo Oscar. University of Washington; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Branch, Trevor A.. University of Washington; Estados UnidosFil: Anderson, Christopher M.. University of Washington; Estados UnidosFil: Szuwalski, Cody S.. National Marine Fisheries Service; Estados UnidosFil: Baum, Julia K.. University of Victoria; CanadáFil: McClanahan, Tim R.. Wildlife Conservation Society; Estados UnidosFil: Ye, Yimin. Food and Agriculture Organization of the United Nations; ItaliaFil: Ligas, Alessandro. Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata; ItaliaFil: Bensbai, Jilali. Institut National de Recheche Halieutique; MarruecosFil: Thompson, Grant G.. National Marine Fisheries Service; Estados UnidosFil: DeVore, John. Pacific Fishery Management Council; Estados UnidosFil: Magnusson, Arni. No especifíca;Fil: Bogstad, Bjarte. Institute of Marine Research ; NoruegaFil: Wort, Edward. University of Plymouth; Reino UnidoFil: Rice, Jake. Fisheries and Oceans Canada; CanadáFil: Hilborn, Ray. University of Washington; Estados Unido