Researchers from the Marine Research Center of the University of Vigo, CIM-UVigo, have just published an article in the scientific journal Animals in which they highlight the importance of integrating genetic information in the management of hake stocks, a research carried out within the Marine Genetic Resources group (ReXenMar) and which is based on research carried out during the period 2015-2020 on board different vessels, both commercial and research, and which included sampling of the five main regions in which European hake (Merluccius merluccius) is distributed.
The article is entitled EST-Microsatellite Types and Structural Scenarios in European Hake Fisheries and is the result of the joint work of researchers Pablo Presa, Alfonso Pita and María Fernández Míguez, members of the Marine Genetic Resources Group, ReXenMar. “In this study we demonstrate the knowledge that can be obtained from different types of genetic markers, each of which is suitable for different objectives,” explain the authors. The first type of markers are called directional and, as they indicate, it is thought that they are measuring the pressure of natural selection; however, they have shown that their variation is compatible with ancient selection pressures and episodes of extreme drift, so they do not measure the current adaptation of fisheries. “Evolutionary novelty, and therefore generating adaptive potential of populations, is detected with balanced markers, which until now have not been the subject of attention in applied studies,” emphasize the researchers, who, thirdly, point out that the detection of demographic dynamics of genetic relevance for fisheries management must be assessed with neutral markers, “that is, those that can measure the current structure and connectivity between fisheries without functional restrictions.”
They argue that European hake forms a metapopulation of two geographic stocks
Among the research results presented in the article, its authors highlight the fact that “directional markers are useless at best and misleading at worst for the delineation of fish stocks and their demographic management, due to their selective bias”. The results observed with directional and neutral markers demonstrate that European hake forms a metapopulation of two geographic stocks with restricted connectivity in the Almería–Orán oceanographic front, each of which responds to a substructure of isolation by distance, for example the North Sea hake being the one furthest from the rest of the Atlantic, both geographically and genetically”. These results come to combat other recent pan-selectionist studies, based on natural selection, which defend the existence of seven genetically differentiated hake stocks, four in the Atlantic and three in the Mediterranean. Knowledge of the number and distribution of fish stocks of a species is vital for its management, as plans have to take into account the dynamics of each of them.
Source: DUVI
