The sea ahead: challenges to marine biology from seafood sustainability

Many have documented the litany of disaster and depletion suffered by living organisms in the world's oceans, where today anthropogenic impacts from fisheries and pollution on biodiversity and resilience are further exacerbated by threats of climate change. At the same time, the demand for sustainable seafood has never been greater. By presenting three challenges to marine biology, this article explores how we may be able to throw light upon practical measures that can mitigate, redress and avert some of the worst future scenarios whilst continuing to supply, and even increase, economic, social and nutritional benefits from seafood. First, I present a rigorous, multi-disciplinary, semi-quantitative ecosystem evaluation framework (EEF) that characterises the essential ecological features of different marine ecosystems and can evaluate the status of threats. The general framework is designed to work in the face of ignorance and quantifies uncertainty. An example is presented from recent work on seamounts. Second, a desperate need for food supplies will almost inevitably lead to further fishing down the trophic levels in marine food webs. Some have argued to do this deliberately to mitigate global problems of hunger, especially in the face of concerns about the sustainability of terrestrial agriculture, and we can be sure that economic pressures and market values for increasingly scarce protein will lead to tendencies of this type. One example is a possible increased exploitation of krill, which at first sight presents vastly increased amounts of protein that could be harvested. Here, I show how large but potentially sustainable levels of catch may be estimated in a precautionary fashion. Third, inter alia, a practical restoration agenda is discussed. The importance of historical reconstruction is exemplified by 'Back to the Future' research which attempts to use quantitative descriptions of past ecosystems to emplace practical restoration goals for management (such as Optimal Restorable Biomass, ORB), while quantifying risks in the management of marine ecosystems from climate and uncertainty. All three areas and their examples represent work-in-progress, and their credibility and utility pivot on the quality of our insight into critical ecological processes and on the widespread adoption of rational, precautionary policies. Moreover, they present profound scientific and human challenges to the science of marine biology.