World fisheries day, celebrated today aims to draw attention to the poor status of many fished species as a consequence of overfishing, habitat degradation, global warming, and pollution. Clearly, we stand far from the key objective of fisheries management, that is, to regulate fishing such that in the long term harvesting is sustainable. Less political and more science-based management has frequently been called upon as a solution and ‘ecosystem-based fisheries management’ is a term often repeated, but rarely implemented. In fact, a recent study by Skern-Mauritzen et al. (2015) showed that out of 1200 reviewed fisheries, ecosystem-based drivers were only accounted for in 24 cases.
I would argue that the inefficient use of scientific knowledge in the context of fisheries management largely stems from the discrepancy between ecological and fisheries research. At universities, fisheries research is typically taught in complete separation from ecology and evolutionary biology, yet basic population and life-history dynamics form the core of fisheries stock assessments. Publication experiences by me and my colleagues show a clear tendency for fisheries scientists to publish their work in fisheries journals and not even attempt to frame their study questions to a broader ecological audience. On the other hand, studies dealing with fisheries are often turned away from ecological journals because fisheries research is considered as a separate field of research rather than applied ecology.
In my opinion, fisheries research and management would greatly benefit from biological considerations about the theory of life histories and the mechanisms driving population and ecosystem dynamics. This strongly opposes the traditional data-driven approach of fisheries research. For example, in fisheries stock assessment the abundance of mature females has a priori no impact on juvenile production unless proven by data, whereas from an ecologist’s perspective the correlation should be obvious (Kuparinen et al. 2012). Having said that, the wealth of data collected by fisheries scientists should be of interest to ecologists and evolutionary biologists: fisheries surveys provide long time series of observations from natural populations, allowing detection of small trends and weak interactions, which would often go unnoticed in small datasets.
For example, the study of contemporary life-history evolution largely stems from phenotypic trends detected in fisheries survey data. Reducing adult body sizes and earlier maturation are obvious in numerous fish stocks (Sharpe & Hendry 2009). Such life-history changes can reduce population renewal ability and productivity, meaning that future fisheries catches will be smaller (Enberg et al. 2009). Nonetheless, fisheries management practices do not account for those, and many fisheries scientists are reluctant to even consider evolution as an issue associated with fishing. One reputed fisheries scientist put this attitude into words during our discussion last year: “I do not believe in fisheries-induced evolution”. Quite a challenge for science-based fisheries management…
In my view, recognizing not only the potential of data provided by fisheries research but also the ecological and evolutionary knowledge available to explain patterns seen in fish stock developments should be a win-win for both the fields. At its best, closer communication between the fields might help to resolve questions fisheries management struggles with and to provide scientific basis for difficult management decisions, such that they become societally and politically more acceptable.
Associate Editor, Journal of Animal Ecology
Enberg K, Jørgensen C, Dunlop ES, Heino M, Dieckmann U (2009) Implications of fisheries-induced evolution for stock rebuilding and recovery. Evolutionary Applications 2, 394-414
Kuparinen A, Mäntyniemi S, Hutchings JA, Kuikka S (2012) Increasing biological realism of fisheries stock assessment: towards hierarchical Bayesian methods. Environmental Reviews 20, 135-151
Sharpe D, Hendry A (2009) Life history change in commercially exploited fish stocks: an analysis of trends across studies. Evolutionary Applications 2, 260-275.
Skern-Mauritzen, M., G. Ottersen, N. O. Handegard, G. Huse, G. E. Dingsør, N. C. Stenseth and O. S. Kjesbu (2015) Ecosystem processes are rarely included in tactical fisheries management. Fish and Fisheries (in press; DOI: 10.1111/faf.12111