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Ecological and evolutionary dynamics of juvenescent marine populations: a comparative study of the European hake in the Atlantic and the Mediterranean

Final Report Summary - EVOLHAKE (Ecological and evolutionary dynamics of juvenescent marine populations: a comparative study of the European hake in the Atlantic and the Mediterranean)

Project context and objectives

Much evidence supports the fact that fishing drives both ecological and evolutionary changes in marine fish populations. Evolutionary changes in the life history traits unveil variations in the genetic composition of populations with potentially negative impacts on their recovery capacity. Fishing also triggers a broad spectrum of ecological effects that modify the inter- and intra-specific relationships and alter the functioning of the marine ecosystems. However, there is still a lack of knowledge on the interactions and feedback between the ecological and the evolutionary processes induced by fishing. The European Fishing Policy highlights that a deep understanding of the ecological processes is a keystone to achieving a more comprehensive and successful management of the harvested species in European seas. To accomplish this goal, the project was developed to embrace the ecological, demographical and evolutionary responses induced by fishing activity on marine fish populations. The main objective was to elucidate the evolutionary demography (coupling population dynamics and life-history traits) of exploited species. The fellow, Dr Manuel Hidalgo, adopted a common basis for the study using a unique over-exploited species of the European coast, the European hake (Merluccius merluccius), which inhabits both the North Atlantic Ocean and Mediterranean Sea. By using several stocks of the same species, the project takes into account the heterogeneity of both fishery patterns and environmental scenarios.

Work performed

Fishery harvesting can cause rapid and genetic-based shifts in phenotypic traits. These phenotypic shifts are often masked by their coincidence with variations in the population abundance. Thus, for managing exploited species it is necessary to integrate the following:

- the responses to harvest by also adopting an evolutionary perspective;
- the environmental influence;
- the complexity of the population sub-structuring.

Therefore, the project concentrates on coupling the information from different fields: fishery-induced selective changes (evolution), population dynamics (ecology-included environmental influence) and population sub-structure (genetics).

Main results

The project has succeeded in achieving both its scientific and training objectives for the period. Dr Hidalgo found evidence of how fishing, climate, and ecological and evolutionary dynamics can interact in a complex and different way for several populations of the same species. The results of this project will substantially contribute towards European excellence and competitiveness in the field of fishery ecology. The implementation of these findings can maximise the efficiency of the fishing assessment measures by increasing the understanding of the ecological processes. This project will certainly expand the success of management measures applied on the exploited fish species of Europe's seas.