Culture of native species provides opportunities for expanding west coast aquaculture, especially since few native bivalves are currently cultured. Further there is interest among growers, regulators and the public in diversifying aquaculture products to include native species and in using suspended cultures to address environmental concerns and help meet growing consumer demand. Assessing ease of growout is generally quicker and easier than assessing hatchery rearing potential, thus we used it is a logical starting point. During summer 2021, we tested suspended growout methods for US West Coast venus clams (Chione spp) in a bay and on the open coast (off a pier; Fig. 1) using several substrates including mesh bags, mesh cages, cages with natural sponge and cages with plastic mats (Fig. 2).
Clam mortality rates were higher on the pier than in the bay (Fig. 3) which may have been due in part to the higher energy environment. While the plastic mats and natural sponges may have helped the venus clams orient their bodies, as in their natural benthic habitat , clam mortality rates were higher in the presence of substrate (Fig. 4). Growth rates (length, height wet weight) did not however differ across container types (p≥0.25).
Once complete, this research will inform aquaculture interests of ideal growout methods, including ideal conditions for local clam survival and growth.