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Forage fish play a pivotal role in marine ecosystems and economies worldwide by sustaining many predators and fisheries directly and indirectly. We estimate global forage fish contributions to marine ecosystems through a synthesis of 72 published Ecopath models from around the world. Three distinct contributions of forage fish were examined: (i) the ecological support service of forage fish to predators in marine ecosystems, (ii) the total catch and value of forage fisheries and (iii) the support service of forage fish to the catch and value of other commercially targeted predators. Forage fish use and value varied and exhibited patterns across latitudes and ecosystem types. Forage fish supported many kinds of predators, including fish, seabirds, marine mammals and squid. Overall, forage fish contribute a total of about $16.9 billion USD to global fisheries values annually, i.e. 20% of the global ex‐vessel catch values of all marine fisheries combined. While the global catch value of forage fisheries was $5.6 billion, fisheries supported by forage fish were more than twice as valuable ($11.3 billion). These estimates provide important information for evaluating the trade‐offs of various uses of forage fish across ecosystem types, latitudes and globally. We did not estimate a monetary value for supportive contributions of forage fish to recreational fisheries or to uses unrelated to fisheries, and thus the estimates of economic value reported herein understate the global value of forage fishes.

Although much work has been done developing system-level indicators for ecosystem-based fishery management (EBFM), few of those proposed include a spatial component. Even in single-species management, time and area closures have been applied without a clear understanding of what their effect might be on identifying overfishing thresholds and other reference points. For EBFM, spatial zoning of the marine environment, including no-take marine reserves and areas where destructive fishing gears are prohibited, may become a prime management tool. Therefore, indicators of the effectiveness of spatial management will be required, along with an understanding of how indicators related to other objectives will be influenced. We review single-species models that have been used to model spatial zoning, including potential bias in assessment and current work on effort reallocation after area closure, as well as available ecosystem-based models and metrics and how they might account for spatial management. Metrics that can be derived from explicitly spatial approaches such as GIS-based ecosystem and fishery evaluations are also discussed.

The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management (EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization.

To safeguard biodiversity effectively, marine protected areas (MPAs) should be sited using the best available science. There are numerous ongoing United Nations and nongovernmental initiatives to map globally important marine areas. The criteria used by these initiatives vary, resulting in contradictions in the areas identified as important. Our analysis is the first to overlay these initiatives, quantify consensus, and conduct gap analyses at the global scale. We found that 55% of the ocean has been identified as important by one or more initiatives, and that individual areas have been identified by as many as seven overlapping initiatives. Using our overlay map and data on current MPA coverage, we highlight gaps in protection of important areas of the ocean. We considered any area identified by two to four initiatives to be of moderate consensus. Over 14% of the ocean fell under this category and most of this area (88%) is not yet protected. The largest concentrations of medium-consensus areas without protection were found in the Caribbean Sea, Madagascar and the southern tip of Africa, the Mediterranean Sea, and the Coral Triangle. Areas of high consensus (identified by five to seven initiatives) were almost always within MPAs, but their no-take status was often unreported. We found that nearly every marine province and nearly every exclusive economic zone contained area that has been identified as important but is not yet protected. Much of the identified area lies within contiguous stretches of >100,000 km 2 ; it is unrealistic to expect that all this area be protected. Nonetheless, our results on areas of consensus provide initial insight into opportunities for further ocean protection.

Bakun, A., Babcock, E. A., and Santora, C. 2009. Regulating a complex adaptive system via its wasp-waist: grappling with ecosystem-based management of the New England herring fishery. – ICES Journal of Marine Science, 66: 1768–1775. We use the New England herring fishery as an example of the unresolved scientific issues pertinent to ecosystem-based management of forage-fish fisheries. The biomass of herring off New England is currently well above maximum sustainable yield (BMSY), leading to pressure for expanded harvests. Associated concerns include: the maintenance of sufficiently abundant forage to meet the current needs of marine mammals and seabirds while supporting the rebuilding of overfished groundfish resources; the preservation of the service functions of a healthy population of pelagic zooplanktivorous fish to prevent possible outbreaks of pests, or hypoxia events; and the limitation of unintended bycatch of marine mammals, seabirds, and juvenile stages of groundfish. Perhaps a self-enhancing feedback loop, involving predation by herring on the early life stages of their groundfish predators, might result in regime shifts that could not be easily reversed. A plausible outcome of these ideas is a dichotomy in management choice between (i) promoting an ecosystem dominated by valuable groundfish resources and (ii) promoting the current ecosystem that features a large herring resource associated with abundant and energy-rich forage for marine mammals, seabirds, and continued high productivity of valuable shellfish resources.

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