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'Kiddie Pools' Boosts Clam Hatchery Seeds

US - The Manila clam (Tapes japonica) was accidentally introduced into Puget Sound, Washington State during the 1930s and 1940s with shipments of Pacific oyster seed from Japan. The commercial farming of Manila clams soon followed.

It now ranks as one of the top shellfish produced in the State. In 2005 the Washington State production was estimated at 3.9 million kilograms with a value of _12.6 million. Supplementing the reliance on natural set of seed, hatchery reared clams are now the major culture method used by farmers to source seed clams for intertidal beach planting. Survivability of seed is correlated to seed size, larger seed has higher survival.

Cost and space to rear large seed is a limiting factor in supplying seed to farmers. Seattle Shellfish LLC, has developed a very simple method to boost small hatchery seed (4 mm) to larger sizes (18 to 20 mm+) via an intermediate nursery system using containers (Kiddie Pools).

From a trial experiment in 2005, through a pilot project to a full scale commercial operation the company have been successful in developing these techniques. They have also begun rearing Manila clams to full grow out commercial size (40 mm and larger) in Kiddie Pools in 12 to 16 months.

The company claims that yields have been as high as thirty kilograms per square meter. They say that the commercial aquaculture interest as well as the restoration/education aspect of these techniques are directly transferable to the husbandry of European Carpetshell clams (Ruditapes decussates) and Venus clams (Venus verrucosa) as well as Manila clams currently farmed in Europe.

"We believe this sharing of information is paramount in the future success of all forms of aquaculture in Europe, the Americas and the world." A company report read.

"Not only have the nursery and grow out methods proven commercially successful; they are a very useful tool to add to community restoration projects. Many times oysters are a key shellfish species in environmental education and community out reach programs, but adding Manila clam culture or European species expands the possibilities for student and adult engagement in restoration work."