Sea Cucumber Culture in British Columbia
Commercial harvesting of sea cucumbers began in 1971 at a small scale. The harvest increased in scale in the 1980’s to about 2000 tonnes by the end of the decade with present fishery yields around 4000 tonnes per year. The fishery is under strict management since stocks have declined and much of the coast is closed to the fishery. Products from sea cucumber include muscle strips (fresh or frozen) and dried skins or sections. The main market for sea cucumber products is China and Japan. While there exists good market potential for sea cucumbers, there has been relatively little effort in Canada to develop the culture technology to rear them in a controled manner. A few trials were conducted for sea cucumber culture, but no significant development to pilot scale and commercial projects has yet taken place.
The species of sea cucumber found along BC’s coastal waters is the giant sea cucumber Parastichopus californianus. They are usually found on substrates where organic material and detritus settles and accumulates. These are usually areas with low current flow. Cucumbers can sometimes be found at the extreme low intertidal level but normally are found subtidally to a depth of 90 metres. Sea cucumbers can live to be about 8 years old and grow to a length of 50 cm. sexual maturity is not reached until the sea cucumber is 5-6 years old. In the summer (June to August) males and females spawn in shallow water. The larvae are planktonic for 7-13 weeks, dependent on temperature, and will then settle and metamorphose. The juveniles seek refuge under seaweed or eelgrass where organic sediments collect. Starfish are the main predators of sea cucumbers.
Since they are echinoderms like sea urchins, some of the technology for urchin culture will be applicable to sea cucumber culture. Urchins are bottom feeders, ingesting organic material, detritus, fecal material and microrganisms from benthic sediments. This feature makes them very appealing for polyculture systems with either shellfish or finfish operations. Studies are being conducted to determine the parameters of sea cucumber culture integrated with finfish operations.
Oyster growers have found that juvenile sea cucumbers form a significant population within the community of organisms that settle and grow on oyster lines. The sea cucumber thrive on waste material produced by organisms such as urchins and oysters. Existence of farmed animals at different trophic levels is the basis of environmentally sound polyculture systems. Sea cucumbers should thrive on benthic areas around fish and shellfish farms where there is an abundant food supply.
The design and construction of containment structures will be one of the first major challenges in the development of viable sea cucumber culture. The containment systems may be benthic, suspended, or a combination of the two. Adequate amounts of naturally available feeds will likely serve as the foundation for grow-out systems, but research will likely be required to optimize diet and sea urchin market condition.
Web sites to consult:
- Fisheries and Oceans Canada:Species and Habitat of Shellfish.
- Fisheries and Oceans Canada:Diseases and Parasites of Shellfish