Little Fish, Big Deal: See What We Mean by Forage Fish
Small schooling species such as sardines, saury, and smelt—commonly known as forage fish—play a critical role in sustaining a vibrant Pacific Ocean. These species eat tiny plants and animals drifting near the surface, turning them into protein that's consumed by bigger fish, seabirds, and marine mammals. Forage species serve as the vital link in the marine food web, connecting microscopic plankton to humpback whales the size of school buses.
The Pacific Coast
This is one of just a few marine ecosystems in the world dominated by cold-water upwelling, where nutrients pulled from ocean depths fuel the growth of phytoplankton at the surface. Small schooling fish swarm to these blooms of life, in turn becoming food for an astonishing array of ocean wildlife. A recent decade-long tagging study revealed that tuna, sharks, seabirds, seals, and whales cross the Pacific every year to feed in the rich marine ecosystem along the West Coast.
Keeping an Eye on the Big Picture
Forage fish account for more than a third of the total global catch of wild marine fish. The bulk of it is used for secondary purposes such as feeding livestock, poultry, and farmed fish. Unfortunately, fishery managers traditionally overlook the critical role forage fish play in marine ecosystems when they establish fishing regulations and catch limits. Fishermen and scientists are becoming increasingly aware that we need to leave more forage in the water as food for the larger ecosystem.
Forage fish are the key link in the food web for...
Albacore tuna and salmon are among the important commercial and recreational species that need abundant forage. One study found that small schooling fish account for 80 percent of the diet of tuna on the West Coast. For salmon, forage fish provide a twofold benefit at the critical point where they make the transition from freshwater to ocean. First, they provide alternative prey for a gauntlet of predatory fish, seabirds, and marine mammals as the bite-size juvenile salmon leave the river. Then, as salmon mature, forage fish become a key food source. The additional calories provided by small schooling prey such as herring and whitebait smelt enable salmon to grow larger, produce stronger eggs, and improve reproductive success.
Whales, seals, and dolphins are among the larger animals that depend on an abundance of forage. A single humpback whale consumes 1,000 pounds of forage a day. A lack of adequate forage can have serious consequences. For example, in 2009 scientists documented 80 percent mortality among pups in a population of sea lions off the coast of California when females left them for a week at a time in search of food.
New research reveals that seabirds need even more forage than previously understood. Researchers discovered that seabird populations around the world experience breeding failures when their main source of prey dips below a third of its maximum population size. Even relatively small seabirds collectively require an incredibly large amount of oil-rich forage such as herring to breed and migrate successfully. A single species, the common murre, collectively devours more than 200,000 tons of forage every year.
Protecting the Bait
In Alaska, the North Pacific Fishery Management Council explicitly recognized the role of an abundant prey base by designating many key forage species off-limits beginning in 1998, with the strong support of commercial fishermen. The Alaska Groundfish Data Bank supported the action, noting that targeted fishing for predator fish and for the prey they need to survive is “akin to burning a candle at both ends.” Fishery managers in California, Oregon and Washington demonstrated similar far-sighted thinking in 2006 by protecting krill, a tiny shrimplike creature that's a principal source of forage for whales and other marine life.
Making the Marine Food Web a Priority
The Pacific Fishery Management Council recognized the importance of forage to a well-functioning ecosystem when it put krill off-limits in 2006 because of its importance as food for other marine life. The council now has the opportunity to continue that stewardship by preemptively setting aside forage species that aren't currently fished but could be at any time. Protecting these species is a concrete step toward sustaining the marine ecosystem that supports our coastal fishing and tourism economy.
Ask the Pacific Fishery Management Council to help ensure a balanced and productive marine food web for generations to come. The council can start by setting aside forage species that aren't currently protected but serve an important role as prey for marine life.
Write the council at email@example.com.
Learn more at www.PewEnvironment.org/PacificFish.