The worst time to buy scallops is after they have spawned because the adductor muscle is soft and discolored and sheds moisture easily. The best time to buy scallops is in the late summer when prices are low and the quality has improved following the spring spawn. Scallop meats are sold by count per pound, with a premium being paid for larger size meats (lower count per pound). The trick to sea scallops is to not pay $10/lb. for water. Dry scallops will feel sticky whereas a soaked scallop will feel soapy or slick. Although very small quantities of U.S. scallops are harvested inshore by divers, the term “diver” scallops refers to a dry scallop that has not been treated by sodium tripolyphosphate. The phosphates allow the scallop to hold more water, sometimes 20% more. Most scallops are treated using phosphates and even dry scallops are often washed in tripolyphosphate.
The U.S. and Canada have strict rules for aquaculture, but China has been struggling with water quality and pollution problems in its coastal environment, according to the Monterey Bay Aquarium. Shellfish farmers there have little control over industrial and agricultural pollution, so it’s unusual for there to be management processes in place to deal with the problem. There is little information available about best management practices for sea scallop farming operations in Asia, according to the aquarium.
Bay scallops are farmed primarily using lantern-shaped nets suspended from long lines underwater either on the seafloor or in a water column. Most bay scallops come from Chinese farmers, although there are some farmers in New England. Bay scallops filter the water so farmers don’t use treatment on them and farming of this species doesn’t create waste.
The majority of farmed scallops are raised “off-bottom,” a method where they are harvested by hand, according to the Monterey Bay Aquarium. Some scallops are raised “on-bottom” in culture plots, meaning they are removed using a heavy net dredge that can harm ecosystems and negatively impact marine life, causing diversity to decline, according to the Monterey Bay Aquarium.
Since scallops are filterfeeders that actually remove plankton from the water, no additional feed is used in bay scallop farming operations.
Escapes and Introduced Species
Although there is little information available about the environmental impacts of Chinese bay scallop operations, the scallop seems unable to survive on their own in China’s cold water and no wild populations have been reported there to date. Operations in Japan and the U.S. don’t represent a risk to other marine life.