Alejandro Ezequiel Rojas
Hoki (Macruronus magellanicus) and southern blue whiting (Micromesistius australis) are marine fish of great economic and ecological value in the Patagonian seas. These species have faced periods of intense fishing pressure, particularly in the Southeast Pacific Ocean, where stocks have been declared depleted. While the IUCN has not yet evaluated these species, their population trends suggest that both could be considered at risk, at least at the local or national level.
Current stock assessments for both species are carried out based on two management units: one located in the waters of the Chilean shelf and slope in the Southeast Pacific Ocean, and another in the waters of the Southwest Atlantic Ocean, including the shelf and slope waters of Argentina and the Malvinas/Falkland Islands. However, these stocks may not align with the actual biological population structure, as there are still uncertainties regarding the population structure and dynamics of these species. Given that fishing policies must be defined based on relatively homogeneous population units, this discrepancy could lead to erroneous predictions in stock assessment models and result in overfishing.
Alejandro Ezequiel Rojas training in laboratory work for RAD-seq library preparation. ©Yésica Álvarez (Universidad Nacional de Tierra del Fuego).
My project aims to address this knowledge gap trough a genomic approach. We will use RAD-seq (Restriction-site Associated DNA) to generate information to study the population genetic structure and connectivity in both species. This will enable us to assess if the current management units (two-stock hypothesis) align with the biological population units. Establishing this baseline is critical for advising on any necessary adjustments to the management units. This will enhance the precision of abundance assessment models, the determination of biologically acceptable catch limits, and contribute to improving the population status of M. magellanicus and M. australis. This knowledge will also contribute to identify priority populations for conservation and marine protected area planning. In addition, the project will help guide future monitoring, improving the understanding of the spatial and migratory dynamics of the species.
We will collaborate with the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP - Argentina) Southern and Subantarctic Demersal Fish Fisheries research group to integrate the project's findings and recommendations with their expertise on the biology and fisheries of these species. As the institution responsible for assessing Argentina's fishing resources and advising the Consejo Federal Pesquero (CFP - the main regulatory body for fishery exploitation in Argentina) on sustainable catch limits and management measures, INIDEP will be a key partner in translating our results into policy recommendations.