Forage fish are the small fish that larger fish eat. Locally, our primary forage fish species are Pacific herring, surf smelt and Pacific sand lance. Surf smelt and sand lance spawn on beaches in the intertidal zone, while herring lay their eggs in shallow water on eelgrass and marine algae. When these eggs hatch, the tiny larval fish float out with the tide to become part of the food chain.
Research in nearby Georgia Strait shows that between 50% and 75% of the diets of Coho salmon, Chinook salmon, lingcod, and halibut consist of forage fish. Local seabirds, including marbled murrelets and rhinoceros auklets, feed directly on forage fish; surf scoters dive underwater for herring eggs that are incubating on eelgrass and other submerged vegetation. While Minke whales eat huge portions of forage fish directly, the resident Orcas depend on small fishes to fatten the salmon they consume. Because forage fish and juvenile salmon depend on nearshore habitat for their survival, they are vulnerable to the impacts of shoreline development. Primary threats to forage fish habitat include: bulkheads, roads, boat ramps, docks, pollution runoff and removal of shoreline and aquatic vegetation. A recent study found that shoreline modification can reduce the survival rate of surf smelt embryos as much as 50%.
Protection of existing high quality forage fish spawning habitat has been identified as a key conservation objective for the San Juans and a high priority for salmon recovery.
FRIENDS and the Washington Department of Fish and Wildlife identified just under 80 miles of potential forage fish spawning habitat, or 20% of local shorelines, in San Juan County during surveys conducted from July 2001 through December of 2003. Surf smelt spawn has been documented at 59 sites in San Juan County, while Pacific sand lance spawn activity has been documented at eight beaches.
Forage Fish Habitat Protection: Documented forage fish spawning sites are protected by state administrative code and local regulations. San Juan County and the Washington Department of Fish and Wildlife review shoreline projects (bulkheads, docks, etc.) with the goal of ensuring that there is no impact to spawning habitat. There are 59 surf smelt spawning beaches, 8 sand lance spawning beaches and 5 herring spawning grounds in San Juan County.
Two stocks of spawning Pacific herring are recognized by Washington Department of Fish and Wildlife in San Juan County. One stock spawns in the Westcott Bay/ Roche Harbor Region, while the other spawns in the East portion of the county, including: Mud and Hunter Bays on Lopez Island, in West Sound and Eastsound on Orcas Island and in Blind Bay on Shaw Island. Due to significant declines in eelgrass, the Westcott bay herring stock has not been documented spawning since 2004.
Species Info
Surf smelt spawn at the highest tides near the water's upper edge on coarse sand and pea gravel beaches. Egg development is temperature dependent with marine riparian vegetation and freshwater seeps and streams serving to maintain lower temperatures during the warmer summer months. Surf smelt are a significant part of the Puget Sound food web for larger predators. Spawning in northern Puget Sound occurs year round, while spawning in central and southern Puget Sound occurs seasonally. The limited extent and upper beach location of surf smelt spawning beaches makes them especially vulnerable to shoreline development and construction activities.
Pacific sand lancespawn at high tide in the upper intertidal area on sandy beaches. The fine sand coats the eggs and likely serves to assist in moisture retention when they are exposed during low tides. It also serves to conceal the eggs from predators. In Puget Sound, the spawning season for sand lance is November 1 through February 15 with larvae commonly found between January and April in the Puget Sound area. Pacific sand lance are a significant dietary component of many economically important resources in Washington, such as juvenile salmon. It has been found that 35% of juvenile salmon diets are Pacific sand lance. They are particularly important to juvenile Chinook with 60% of the juvenile Chinook diet represented by Pacific sand lance. Sand lance are also a key prey item for seabirds, including rhinoceros auklet
and the threatened marbled murrelets. The limited extent and upper beach location of sand lance spawning beaches makes them especially vulnerable to the direct and cumulative effects of shoreline development.
Pacific herring utilize shallow subtidal habitats for spawning and juvenile rearing. Herring stocks in Puget Sound spawn at specific sites or grounds. Herring spawn from the upper intertidal region to a depth of 40 feet, but most spawning is between 0 and 10 ft MLLW. Pacific herring spawning in the San Juans occurs from late January through April. In San Juan County, herring generally spawn on eelgrass (Zostera marina) or the fibrous red alga Gracilariopsis. The limited range of herring spawning areas and their location in nearshore marine environments make Pacific herring spawning grounds vulnerable to impacts from shoreline and upland development.
Pacific herring are an important prey item for many organisms, including marine mammals, seabirds and fish. Pacific herring have been found to comprise 30% to 70% of diets for the following fish species: Chinook salmon, Coho salmon, Pacific cod, walleye Pollock,
lingcod and Pacific halibut. Pacific herring spawn sites also play an important role in the life history characteristics of scoters; the eggs provide a critical energy source just before the birds make their annual journey to their Alaskan and Canadian breeding grounds.
