Is climate change moving the goalposts for fisheries management?

Current evidence indicates that, compared with loss of biodiversity in freshwater and terrestrial ecosystems, the rate of loss in marine systems is relatively slow (N.K. Dulvy – Recent marine extinctions, this meeting). This is not a cause for complacency, and the rate of loss is probably underestimated, but it challenges us to explain why protection of marine biodiversity is an urgent concern, when assigning priorities for research and management. Global food security provides a strong justification. It requires sustainable marine fisheries, but, in addition to being threatened by overfishing, climate and other aspects of global change (acidification due to CO2, rapid increase in some nutrients), fish stocks are becoming less resilient due to loss of biodiversity at infra-specific as well as at species and ecosystem level. A second justification is that we know too little about biodiversity changes in marine ecosystems to make well-informed decisions (notwithstanding the Continuous Plankton Recorder, www.sahfos.org , which provides among the longest and most geographically and taxonomically extensive time series and sample archives for any ecosystem on the planet). The protection of charismatic marine mammals is of course a third justification, which has had huge popular and political support for many years.