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. The UHA therefore hired a consultant biologist
to co-ordinate 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 in British
Columbia through the UHA’s West Coast Geoduck
Research Corporation:
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 provides 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
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 which 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.
Assessing Potential Habitat Impacts
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
