Biomass of Fish in the World Ocean, 1950–2050: A Century of Decline?

Overexploitation of the world’s fish resources has caused serious decline in fish populations, and there is widespread concern for how the oceans can contribute to future food security. The oceans now supply less seafood than in the 1980s, while the global fishing capacity is increasing. Projections for the future of fisheries are conflicting, yet have demonstrated a very strong global impact. The predictions are, however, highly questionable as they are based on sparse and incomplete information, and biased toward the well-studied parts of the world. In this presentation, I review available hind-cast studies and future scenario projections, and show results from a new study of how fish abundance in the world oceans has changed since 1950, integrating information from a large number of ecosystems globally. I stress the increasing need for modeling of the world’s fish supply under alternative climate change and management scenarios for use in global environmental outlooks and to advice governments. Such scenario outlooks will be developed by a new, major international research initiative, “Nereus – Predicting the Future Ocean” of the Nippon Foundation and the University of British Columbia. The Nereus program, which involves a network of academic and international organizations with expertise in global ocean modeling, is based on detailed analysis of how the seafood resources in the world oceans have been and will be impacted by human activities, and uses an interdisciplinary approach that will advance our scientific capability to integrate ecological, economic, social, and governance factors in future global scenario modeling. The program is concerned with capacity building and how to communicate the state of the oceans. This is not the message that the world’s fish populations are gone and that it is too late to reverse the situation. It is not too late; fish continue to be the most important source of protein for millions of peoples, and notably so in developing countries. But we need to communicate and bring about change to how we exploit the oceans if our children and grandchildren are to enjoy seafood and experience a healthy ocean with all the services it can provide.