Summary

Global production and trade in small pelagic fish (SPF) are affected by complex interactions between physical, ecological and economic systems, which give rise to relatively long-term, asynchronous cycles in SPF abundance and distribution. These cycles can have serious impacts on local SPF fisheries' production, but because they tend to be counterbalancing, global production of SPF tends to remain relatively stable. Nevertheless, recent patterns of landings indicate that most SPF are being harvested at or near their maximum yield levels, which in the face of increasing demand is expected to result in rising prices in supply-limited markets. Adding to these concerns are the uncertainties of climate change, which leads us to consider important economic issues related to SPF fisheries production, starting with how the redistribution of SPF resources affects respective rates of resource utilization, particularly when SPF move between independently managed fishing zones. This entails an associated issue, the time preferences for experiencing the range of benefits from SPF resources among nations sharing access to these resources. Because the ecological and economic impacts of climate change will extend well beyond directed SPF fisheries, we consider the economic impact of a climate–SPF regime shift from an ecosystem perspective. Of interest here is the full range of economic benefits SPF resources provide; not only their commercial value, but as prey for commercially valuable predators, and for recreational and non-commercial predators. In this context we examine the socially optimum use of these resources, balancing the benefits from commercially harvesting SPF with those from leaving them in the ocean ecosystem.

Summary

The Small Pelagic Fish and Climate Change (SPACC) program was created to facilitate research on the dynamics of populations of small pelagic fish, including anchovy and sardine. These populations exhibit large variations in size, extent, and production on the scale of decades. At times, anchovy and sardine alternate in abundance. Collectively, small pelagic fish often occupy a central role in the food web they occur in, often described as a wasp-waist ecosystem. Humans are an integral part of those ecosystems. Variability of populations of small pelagic fish is believed to be due primarily to variations in climate and fishing, but the mechanisms of these relations remain unknown in most cases. It is also uncertain whether these ecosystems alternate between states, e.g. regimes, and whether inherent variability may limit our ability to predict their future states. The fisheries for populations of small pelagic fish are increasingly global in nature. While the global catch of small pelagic fish constitutes approximately one quarter of the world fish catch and has been relatively constant during the past several decades, the catch of individual taxa and stocks varies much more. The management of these fisheries will be challenged by increasing demand for human consumption and mariculture in light of their finite and variable production, importance within the ecosystem, and unprecedented climate change, and will depend on both science and governance. We recommend continued, global research on climate change effects on small pelagic fish, and its periodic assessment for use by decision makers.