A few thoughts have arisen since reading the contributions on the topic of ’Reconciling fisheries with stopping BD loss’. I think the problem in fisheries is serious and it is high time we did something. If we cannot stop declining trends in commercial stocks, then how can we seriously talk of stopping biodiversity loss at higher trophic levels?

One of the practical solutions (however, unpopular, I assume) is to totally change the basics of fisheries management by moving towards simple and commonly understandable and acceptable approaches. Can’t we say "Don’t catch juvenile fish and let them spawn!", so that the management target would be that 100% of fish caught should be mature? Currently, a lot of money and time is being spent for performing fish stock assessments and formulating management advice, but several internationally managed fish stocks in Europe are overexploited and therefore at risk. Reduction of fishing effort has been shown to be an effective method to protect the commercial fish. However, what is the result if the catch still consists of substantial amounts of immature fish?

Another point is that our knowledge is mostly confined to commercial fish. But fish communities consists of non-commercial fish, the species diversity of which might actually be much higher than that of the exploited component. How much do we know of the dynamics and status of non-target fish that play major roles in ecosystems by acting as intermediate hosts of parasites or being essential prey and/or predator or food and/or niche competitor for commercial fish? I would say that this is the place where scientists can seriously say that more research is needed.

The Ecosystem Approach to Fisheries management (EAFM) is currently commonly accepted within EU. However, there is no common understanding regarding what this precisely means and what should be done now. The problem partly is that it is difficult to include ecosystem knowledge into the current fisheries models. And this perhaps gave Ferdinando Boero reason to say that fisheries scientists don’t use knowledge and information from food-web processes. So, the re-marrying of the divorced fisheries and marine biology/ecology science is more difficult than expected/believed.

Henn Ojaveer,
Estonian Marine Institute
University of Tartu