The current knowledge status of the genetic population structure of the European sardine (Sardina pilchardus): uncertainties to be solved for an appropriate fishery management

Abstract

To achieve sustainable fisheries implies that resources’ management is carried out in accordance with biologically and ecologically relevant processes. In this context, to infer the boundaries of the genetic stocks along their distribution is crucial to avoid the depletion of genetic diversity induced by fishing pressure. Despite its remarkable ecological role and commercial interest, there are still many uncertainties about the genetic population structure and local adaptation processes of the European sardine (Sardina pilchardus) along its distributional range. Our analysis revealed that in addition to the uneven genetic study effort throughout its distribution, there are discrepancies when it comes to delimiting populations, especially in the waters surrounding the Iberian Peninsula. Also, powers of the genetic markers applied in the studies were examined, showing that allozymes detected a larger number of significant pairwise values of genetic differentiation, while mtDNA-RFLP detected a greater degree of differentiation among genetic stocks. Moreover, large values of genetic diversity in all the locations were identified regardless of marker type. Thereby, we provide a discussion of updated knowledge, contributing to shape long-term and genetically sustainable harvest strategies for this pelagic fish, since our findings indicate a mismatch between the genetic stocks and the managed stocks currently defined.