Scallop suspension farming praised

Published on
October 20, 2009

While blaming wild scallop dredging for damaging the environment, conservationists are praising cultivated scallops from Asia.

In the United Kingdom, Lyme Bay, the Firth of Lorn and Cardigan Bay have been closed to scallop dredging due to diminishing scallop stocks and concerns about seabed conditions. A scientific report issued 13 October by Scottish Environment LINK blames scallop dredging for killing seabed algae and urges hand-picking by divers instead. The Shellfish Association of Great Britain is appointing an expert to develop a code of conduct for the scallop industry.

But the U.S. Web site Sustainable Sushi says farmed scallops are “a good choice as long as they are suspension farmed.” If the scallops are raised on suspended lines or nets, there is no seabed damage. As filter feeders, scallops consume no wild fish, do not require artificial feeding and actually clean the water.

China is the volume leader in cultivated scallops, with annual production of bay scallops (Argopectens irradians) at more than 5 million metric tons, shell-on. Japan produces the larger “hotate” sea scallop (Patinopecten yessoensis). According to a scallop market report from Seatrade International Co. of New Bedford, Massachusetts, the main sizes in count per pound from Japan are 10-20s (mainly in the 18-23 range) and 20-30s, while China mainly exports 30-40s and 40-60s with some 20-30s.

Yearly Japanese scallop landings amount to roughly 500,000 metric tons, about equally split between wild and farmed. The large size of Japanese scallops is partly due to the species cultivated, and partly because they are allowed to grow longer to meet Japanese market preference. Chile and Peru produce much smaller quantities of small-sized scallops, competing with China.

In Japan, live scallops are grilled on the halfshell with soy sauce. For frozen meats, the “string” that runs along the edge of the shell, the hepatopancreas (gut sack), and the roe are removed.

The United States and Hong Kong import only the adductor muscle, but for the European Union, where France is the leading scallop consumer, the gonads roe are sometimes included, according to Kazuto Toyoshima, head of the Hiranai City Fishery Cooperative.

Hiranai, in Aomori Prefecture, is the top port for cultivated scallops with average landings of about 30 metric tons per day. September is the peak of flavor for scallops in this area. Glycogen, which imparts sweetness, increases throughout the summer but begins to decline with colder weather.

Japan makes extensive use of scallop byproducts. The string is dried into a beer snack similar to the dried squid that is a standard snack with beer. They are sometimes flavored with chili pepper, seaweed or cheese. Ground shells are used to add grip to asphalt surfaces in snowy areas. When only the adductor is exported, the other parts can be used as fish feed for sea bream; they are high in taurine, a necessary amino acid lacking in soy-based fish feeds.

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Contributing Editor reporting from Osaka, Japan

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