MYFISH (Maximising yield of fishery)

Maximising yield of fisheries while balancing ecosystem, economic and social concerns.

The idea of managing fisheries to obtain the largest sustainable yield was formalised in the 1950s and has since been a topic of much debate in fisheries. The derivation of the original relationship was based on assumptions of constancy in vital rates such as growth, maturation, natural mortality and stock-recruitment relationships. Over time, it has become clear that these assumptions are rarely fulfilled and even if they were, the sum of individually estimated MSYs often exceeds that which can be obtained when the interactions are considered.

MYFISH will provide definitions of maximum sustainable yield (MSY) variants which maximize other measures of ‘yield’ than biomass and which account for the fact that single species rarely exist in isolation. Hence, MYFISH will redefine the term ‘sustainable’. MYFISH aims at integrating the MSY concept with the overarching principals of the Common Fisheries Policy: the precautionary and the ecosystem approach.


As a result this project, reports on definitions, framework, decision support tables, practical constraints, implications and responses, stakeholder priorities, as well as a website and dissemination status reports will be published.

Timeline approach

Activities of  MYFISH are:

  • Define, general and regionally relevant MSY variants. The tools necessary to estimate these and evaluate the effect on ecosystem, economic and social constraints are developed
  • Evaluate the effects of aiming for different ecosystem, economic and socially constrained MSY variants on yield and risks of passing limiting constraints are evaluated
  • Operational implementation of MSY variants is discussed
  • Synthesise, common patterns and guidelines and needs for further research, monitoring and assessments are inferred from pan-regional analyses
  • Disseminate, dissemination to stakeholders, managers, the scientific community and the broader public