Don Rothaus, WDFW
Commercial geoduck clam harvest is managed by the Washington Department of Natural Resources. WDFW is responsible for biological management and enforcement of WDFW regulations of this valuable resource. A competitive bid process is used to sell harvest contracts to the highest responsible bidder. Successful bid divers are required to obtain a WDFW fishery license prior to commercial harvest.
State geoduck harvest areas receive biological surveys by WDFW biologist/divers prior to commercial harvest. The surveys are used to determine average geoduck density, average weight, and to characterize the habitat present. The harvest areas are called “tracts.” All geoduck tracts are in marine subtidal areas between the -18 and -70 foot water depth contours (at the zero tide level, or mean lower low water). When eelgrass beds are present, geoduck tract nearshore boundaries may be deeper than -18 ft. (MLLW). Where Pacific herring habitat is present, geoduck harvest must be deeper than -25 ft. (MLLW) and -35 ft. (MLLW) during the herring spawning season. Geoduck tracts are found throughout Puget Sound on soft bottom substrates. There are no known tracts on the outer coastline of Washington.
Commercial Geoduck Tracts
Annual subtidal scuba surveys, to estimate the abundance and distribution of the geoduck clam (Panopea generosa) resource, began in 1967 in Washington State. About 110 million pounds of geoducks, distributed throughout Puget Sound at water depths down to -60 feet (MLLW), were initially identified. In 1970, the Washington Legislature established a commercial geoduck clam fishery and designated the Washington Departments of Fisheries (Fisheries subsequently merged with the Dept. of Wildlife) and Natural Resources (DNR) to co-manage the fishery. WDFW is primarily responsible for biological management of the fishery and DNR is primarily responsible for harvest management. The year-round fishery generates revenue for the state (about 22 million, $US) through a competitive bid process and sale of the rights to harvest shares of the quota on discrete geoduck “tracts.” In 1985, a wild stock geoduck fishery Environmental Impact Statement (EIS) was completed. In 1994, the Stevens Treaty tribes affirmed their rights to harvest shellfish resources in common with the citizens of the state (50:50 sharing), commonly known as the Rafeedie Decision. The treaty tribes have fully participated in the commercial geoduck clam fishery since 1995.
In 1997 state and tribal co-managers adopted a deterministic age-structured equilibrium yield model for the geoduck fishery (Bradbury et al., 2000) and recommended a annual total allowable catch (TAC) rate of 2.7% of the commercially available geoduck biomass in six management regions. There has been a trend of increasing geoduck TAC due to discovery of new commercial geoduck beds, upgrades to health classifications in some areas, and tribal access to harvest nearshore geoducks that were unavailable to non-tribal harvesters due to statutory constraints. It is expected that this trend of increasing TAC may reverse as decreases in biomass from fishing outpace discovery of new beds and increased fishing areas from health classification upgrades.
In 2001, the wild commercial geoduck fishery EIS was updated and a Final Supplemental EIS was completed. In 2008, a federal Habitat Conservation Plan was completed for the wild geoduck fishery. Both of these documents can be found at Dept. of Naural Resources website. State Environmental Policy Act (SEPA) Environmental Assessments are completed for state harvest areas and are part of SEPA compliance for state harvest auctions.
Historic Landings: Commercial wild stock geoduck fishery landings and ex-vessel value in Washington.
Geoduck tracts are only open to harvest when they are safe for human consumption. Tracts are classified by the Washington Department of Health, and area classifications can be viewed at the DOH Office of Shellfish and Water Protection (OSWP) . Biotoxin testing is also done on a regular basis to determine if geoduck tracts can continue to be harvested.
How long can geoducks live?
Geoducks are long-lived, with one sample in Washington aged at 160+ years old. The average for geoducks, on unfished beds, is 46 years old.
What about illegal harvest?
The high value and wide distribution of geoducks increases the risk of illegal harvest. It is important for those who suspect illegal harvest to immediately contact WDFW Enforcement with identification information for the harvest vessel and participants. Do not attempt to directly contact someone who is illegally harvesting.
How do geoducks reproduce?
Geoducks are broadcast spawners (into the water column), and spawning is often observed to be synchronous, meaning the males and females “release” at the same time. Fecundity (number of eggs) is reported as high as 10 million eggs per year per spawner. Geoducks are known to be “trickle spawners”, releasing gametes over a season extending from early Spring to early Autumn. When eggs are fertilized, they metamorph into larvae which may be floating in the water for 3-5 weeks before settling and digging into the substrate.
Where are geoducks found?
Geoducks are distributed throughout Puget Sound in soft substrates (including mud, mud/sand, sand), and are abundant in South/Central Puget Sound and northern Hood Canal. The vertical distribution of geoducks is from the low intertidal zone (+1.0 feet) to -300 feet (~100 meters of water depth)
How do geoducks grow?
Growth varies from area to area, depending upon substrate depth and environmental conditions. Growth (measured as shell length) is generally rapid from years 0-15 and then the rate slows and the shell thickness increases. Average shell lengths range from 12.0 cm (Dallas Bank) to 16.8 cm (Fishermans Point), (Hoffmann et al., 2000).
How large can geoducks become?
The maximum mass measured in Washington state from a WDFW survey sample was 3700 grams or 8.16 pounds (Adelma Beach, 11/8/2000). The Puget Sound average geoduck weight from survey samples is 938 grams or 2.07 pounds.
How is this wild stock geoduck fishery managed for sustainability?
An important tool for biological management of this fishery is development of a sustainable harvest rate. The most recent yield model was developed by Bradbury, et al. (2000). The harvest rate is 2.7% of current stock estimates, and is based on biological parameters of geoduck clams including natural mortality, growth, maturity, and selection into the fishery. Another cornerstone of responsible management is to survey commercial geoduck tracts to obtain estimates of biomass. Discrete geoduck “tracts” are sampled for geoduck density and weight, to estimate pre-fishing biomass prior to harvest. Following harvest, tracts are re-surveyed to corroborate harvest reported on fish tickets and to establish a post-fishing biomass estimate. Accurate catch accounting is also important for fishery management. The DNR harvest monitoring program assures harvest occurs within designated tract and that harvest is accurately reported.
How are other species protected during geoduck harvest?
To minimize impacts to benthic species, selective harvest gear is used (water jet) during commercial tract harvest, and geoducks are individually harvested. Sensitive spawning, nursery, and migratory habitat of other important marine species (including forage fish, crab, and salmon) are identified and excluded from geoduck harvest areas.
What else is being done to assure good management of geoduck clams?
In addition to harvest-related surveys, other geoduck bed surveys are undertaken to improve the precision of biomass estimates and to verify biomass in areas which may have experienced unexpected mortalities from environmental change or illegal harvest activity. On-going studies are undertaken to improve estimates of mortality, growth, recruitment, recovery of harvested tracts, and to evaluate potential impacts to other marine and marine-water-dependent species.