Two words have gotten a lot of attention in the fisheries news over the last year: “forage fishes.” So what are they, and what’s the big deal? Although the definition can be hazy, forage fishes are generally small, energy-rich fishes that serve a key ecosystem role as prey for larger fish, marine mammals, and seabirds. Pacific herring, capelin, eulachon, and Pacific sand lance are some of the main forage fish species in Alaska marine waters. Forage fishes can also include juvenile stages of larger fishes. For example, juvenile walleye pollock and juvenile salmon are important prey items in Alaska.
Because they are such an important part of the ecosystem, forage fishes have emerged as a major conservation concern worldwide. In some areas there are massive commercial fisheries for forage species, such as the sardine and anchovy fisheries off the coast of Peru. Removing too many of these fishes has the potential to disrupt the functioning of ecosystems. In Alaska, conservation and management of forage fishes varies depending on the species. Juvenile groundfish and salmon are regulated by the state and federal management practices that cover their adult stages. Pacific herring are targeted by commercial fisheries and are managed by the state of Alaska; in federal fisheries they are considered “Prohibited Species” and cannot be retained. The primary way that forage fish conservation is promoted in Alaska’s federal fisheries is through protection of a forage fish group that includes almost all of the forage fishes found in Alaska, from smelts (capelin, eulachon) to krill. For this group, commercial fishing is prohibited and retention of bycatch is sharply limited to provide incentives to avoid such bycatch. This conservation measure is part of the AFSC’s ecosystem approach to fisheries management: these fishes are considered so critical to the ecosystem that no fishing should be allowed on them at all.
Monitoring forage fish populations is an essential part of continuing forage fish conservation, but doing so presents many challenges. The survey methods employed to monitor abundance of commercial fishing (mostly using a bottom trawl) are not well suited for catching small fishes that often live in the upper parts of the water column. As a result, REFM scientists are researching how to use proxy data as indicators of forage fish abundance. For example, a nearshore survey conducted in partnership with the Alaska Department of Fish & Game and using a net with very small meshes may provide insight into capelin and eulachon abundance. Acoustic data is being used to generate data on the abundance of krill. It may also be possible to use the presence of forage species in predator diets (for example, halibut and tufted puffins) as an indicator of which species are abundant. The latter approach is based on the notion that predators are likely to be much more effective samplers of the environment than a scientist with a net. More information on forage fishes in Alaska can be found on the Ecosystem Considerations page (http://access.afsc.noaa.gov/reem/ecoweb/Index.php) and in the forage fish appendix to the annual Stock Assessment and Fishery Evaluation reports for the Gulf of Alaska (http://www.afsc.noaa.gov/refm/stocks/assessments.htm).
