Science and Research

The UHA became actively involved in geoduck and horse clam research starting in 1994. We realized that government agencies did not have all of the funds, equipment, or staff necessary to conduct the research required to ensure a safe and sustainable fishery.


Accurate calculations of annual Total Allowable Catch (TAC) require accurate estimates of geoduck density, geoduck bed area (commercial geoduck habitat), and geoduck average weight for each region fished in British Columbia. Therefore, the UHA hired a consultant biologist to coordinate the industry’s science and research efforts.


To ensure the most comprehensive collection of data and expert analysis, the most knowledgeable people are brought together with a common goal of sustainability. Active research partners include UHA members (owners, skippers, divers, buyers), UHA biologists, DFO scientists, independent third party biologists, and First Nation groups in British Columbia. Today, UHA members and consultants design and implement the following research projects in co-operation with DFO and First Nations through the West Coast Geoduck Research Corporation:

Density survey

Geoduck and Horse Clam Density Surveys


The UHA has actively surveyed geoduck beds (commercial geoduck fishing locations) annually since 1994 to estimate the population biomass (number of geoducks) in different regions of British Columbia. There are over 4,000 geoduck beds on the coast of BC and over 70% of these beds have been surveyed. Many of these beds (25%) have been surveyed multiple times in order to confirm that harvest rates are sustainable. Data collected from these surveys provide the density and area information required to determine the annual Total Allowable Catch (maximum amount of geoduck permitted for a sustainable harvest that year) and to ensure a sustainable resource.

During each density survey, divers work in pairs, counting geoducks one metre on either side of transects (lead lines) randomly placed on the ocean floor within geoduck beds and record their observations on waterproof data sheets clipped to their metre sticks. The results of each survey are analyzed and reviewed by DFO and the UHA, to ensure that only the target harvest rate of 1.2% to 1.8% of the current biomass is harvested annually.


Estimating Bed Area with Remote Sensing


The UHA and DFO cooperatively developed techniques to accurately map the location of geoduck beds (commercial geoduck fishing locations) with remote sensing equipment. This data refines the area estimates of commercial geoduck beds required for calculating the TAC. Hydroacoustics (echo sounders) are used to survey areas from the surface and then software predicts the type of substrate under the vessel. These substrate predictions are then correlated with fishing and survey information in order to map geoduck beds.

Biological samples

Biological Samples


A number of biological samples of geoduck clams are collected each year and submitted to DFO in order to estimate life history parameters such as age, growth rates, average size, recruitment rates, and mortality rates. Accurate estimates of these parameters are required to estimate sustainable harvest rates. We’ve collected and sampled thousands of geoducks since 1994.


Long-Term Geoduck Research Plots


Between 1990 and 1992, the UHA and DFO established three research sites that are closed to commercial fishing and reserved to study the impact of fishing on geoduck populations. These plots are permanently marked underwater on the west and east coasts of Vancouver Island, British Columbia. A UHA biologist and experienced divers, in collaboration with DFO, conduct the necessary surveys and maintenance of the research plots. These sites provide information on geoduck recruitment, mortality, growth, population trends, harvest efficiency, and the influence of conservative and aggressive exploitation rates on these parameters.

Large and a small research boats beside each other

Assessing Potential Habitat Impacts of Commercial Geoduck Harvest


The UHA worked with DFO and other industry partners to complete a large scale investigation of the potential effects of commercial geoduck harvesting on the ocean floor and surrounding sensitive habitats like eelgrass meadows. These studies indicate that the commercial geoduck harvest has no significant, long-term effects on the structure of the ocean floor, the small organisms that live in the sediment, or the plants and animals on the surface of the floor. Click here for the summary of this research.


Show Factor Research


The geoduck show factor is defined as the proportion of the geoduck population visible to survey divers and fishermen at a given time. A good estimate of proportion geoduck showing is key to the accuracy of geoduck biomass surveys in British Columbia. Researchers need an estimate of the proportion of geoducks visible to survey divers. Show factor research is used to establish the best time of year, weather and tides to complete geoduck surveys.

Diver with survey equipment looking at the water from the boat

Additional Geoduck and Horse Clam Research


The UHA has provided DFO with funding for other projects, such as geoduck disease studies and DNA research. Climate researchers have used age and growth data from long-lived geoducks to study ocean trends and correlate growth to sea conditions.


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