This paper reviews abundance and catch levels in around half of global fisheries (those for which information is available). It finds that, on average, fish stocks are increasing in these regions. Fisheries that are managed intensively tend to have more fish than those that are not. Management intensity is defined by a “fishery management index”, and refers to whether levels of fishing are kept below a certain target for each fishery.
Around 19% of global fish stocks with low levels of fish are also fished less, and thus are in a position to recover.
The paper only assesses the stock levels of individual fish species. As the authors point out, it does not account for the status of the wider marine ecosystem, nor does it consider social or economic sustainability.
Regarding the other half of fisheries - i.e. those not assessed in this study and for which information is not available - the paper suggested that, since these fisheries tend to be less intensively managed, fish stocks there are likely to be low and declining. A lack of data, however, makes it difficult to verify this speculation. The authors call for more research in these regions, particularly since fisheries in “data-limited regions” are an important provider of food for many poor people.
Marine fish stocks are an important part of the world food system and are particularly important for many of the poorest people of the world. Most existing analyses suggest overfishing is increasing, and there is widespread concern that fish stocks are decreasing throughout most of the world. We assembled trends in abundance and harvest rate of stocks that are scientifically assessed, constituting half of the reported global marine fish catch. For these stocks, on average, abundance is increasing and is at proposed target levels. Compared with regions that are intensively managed, regions with less-developed fisheries management have, on average, 3-fold greater harvest rates and half the abundance as assessed stocks. Available evidence suggests that the regions without assessments of abundance have little fisheries management, and stocks are in poor shape. Increased application of area-appropriate fisheries science recommendations and management tools are still needed for sustaining fisheries in places where they are lacking.
Hilborn, R., Amoroso, R.O., Anderson, C.M., Baum, J.K., Branch, T.A., Costello, C., de Moor, C.L., Faraj, A., Hively, D., Jensen, O.P. and Kurota, H., 2020. Effective fisheries management instrumental in improving fish stock status. Proceedings of the National Academy of Sciences.
Read the full paper here. See also the Foodsource resource How do food systems affect fish stocks and marine habitats?