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- Sustainability Summary
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.
Health & Nutrition
- Total Fat1.00g
Adult bay scallops can reach up to 3 in (7.5 cm) in length. Their shell valves are convex with a more inflated lower valve. The surface of their shells contains 19 to 21 strong, somewhat square ribs. Their lower valves are light in color, usually white, while their upper valves are dark brown to dark grey with darker markings.
Bay scallops are short-lived, living only a maximum of 1 to 2 years, which is noticeably short relative to other mollusks. They spawn only once during their life cycle after one year of age. Mass spawning events take place almost always in July, each releasing a few million eggs. Bay scallops are hermaphroditic; however, only eggs or sperm are released at any one time in order to prevent self-fertilization.
Bay scallop larvae settle onto stable eelgrass beds and other submerged aquatic vegetation, such as macroalgae. Juveniles use a variety of epibenthic substrates for attachment and do not depend solely on submerged vegetation. Aquatic vegetation provides an above-sediment attachment surface that allows the scallops to grow for a short period before dropping to the seafloor. Adults do not attach to one another or on substrates.
Bay scallops principally filter feed on diatoms using ciliated gills. Common predators include mud crabs, starfish, cownose rays, knobbed whelks, oyster drills, scup, and blue crabs.
Bay scallops can be found in the western Atlantic and range from the north shore of Cape Cod, Massachusetts down to Laguna Madre, Texas. There are three subspecies: Argopecten irradians irradians ranging from Cape Cod to New Jersey, Argopecten concentricus ranging from New Jersey to Chandeleur Islands in the Gulf of Mexico, and Argopecten irradians amplicostatus ranging from Galveston, Texas to Laguna Madre. However, they do not occur continuously along this range. The coastal environments of South Carolina and Georgia are not suitable for scallops.
They can be found between depths of 0-66 ft (0-20 m) in water temperatures between 75°F-79°F (24°C-26°C) although they prefer 68°F (20°C) temperatures. Bay scallops can be found in bays, sounds, and estuaries. They rely on eelgrass and other submerged aquatic vegetation to complete their life cycle, especially when they settle out of the water column in the juvenile stage.
Bay scallops are managed at the state-level. Quantitative stock assessments are not available for the New York or Massachusetts fisheries, but in 2010 Massachusetts began collecting catch-per-unit-effort (CPUE) data. The data shows that CPUE ranges from 28 live pounds per hour to 47 live pounds per hour. However, the data collection began after abundance was already low, so target reference points do not exist. Fishing mortality estimates are also unavailable.Management:
Between 2009 and 2014 in the United States, 97.3% of bay scallop landings occurred in New York and Massachusetts. At least 75% of all US bay scallop landings are made in Massachusetts. There is also a fishery in North Carolina. A recreational fishery exists in Florida, but not a commercial fishery.
Today, abundance in New York and Massachusetts is low relative to its historical abundance before the 1980s. The population decreased sharply in the 1980s and again between 1992-1996. Brown tides and water quality degradation that damaged essential eelgrass habitat were responsible for mass scallop mortality in the 1980s, and a second brown tide event in 1995 was responsible for the second decrease. Landings began to increase in 2004, but today populations have only partially recovered to pre-1980s levels. This is likely due to low densities of spawning stock which leads to low fertilization success. Eelgrass beds, its optimal habitat, have also declined. Formal stock assessments are not conducted, but landings suggest low biomass.
Bay scallop populations in North Carolina never recovered completely from a red tide in 1987 and hurricanes throughout the 1990s. The stock is now vulnerable to environmental events, cownose ray predation, and fishing, making the current status depleted. Under a Bay Scallop Management Plan, the North Carolina Division of Marine Fisheries closed both the commercial and recreational season indefinitely to allow for population recovery.
Specific aspects of the bay scallop fishery are regulated at the state-level, such as:
- Size limit
- Daily catch limit
- Seasonal closures
- Gear restrictions
- Open and closed areas for shellfish harvest
Other management decisions such as bycatch limits and habitat closures are made at the local level. Permits may be required for harvest within their jurisdiction.
Bay scallops are also farmed in addition to being wild-caught. In general, scallops account for the second greatest proportion of global mollusk aquaculture production. Two major aquaculture operations exist in the United States in Massachusetts and Florida. The US also imports farmed scallops from China, ranging from 4,400 to 15,400 tons (4 million to 14 million kilograms). About half of US scallop consumption (including other scallop species) is imported.
Scallop aquaculture production methods include spat collection and sowing culture, hatchery, nursery, and grow-out. There are minimal concerns regarding common aquaculture features such as effluent, operational impacts on habitat, indirect mortality of other species, chemical usage, escapes, disease, and sourcing for broodstock.
Much of the stock for farmed scallops comes from natural or passive settlement. The removal of wild scallops, however, is not expected to have negative impacts on the wild stock. In fact, it is beneficial in reducing the ecological risks associated with domestication selection across generations.
Impact on Stock
In general, bay scallops can be relatively resilient to fishing pressure because they are fished between spawning seasons and when they experience mortality during the second year. Thus, fishing does not affect their reproductive capacity. However, red and brown tides and increased rates of predation combined with fishing pressure has resulted in large population declines and slow recovery.
The fishery uses towed dredges, taking place on sandy areas adjacent to eelgrass beds. Dredges are rarely used on the eelgrass habitat itself, which would lead to dramatically decreased shoot densities and eelgrass biomass. Eelgrass appear to be somewhat resilient to dredging activity in the winter months when the fishery is active.
Complete bycatch data does not exist for the fishery, although some local jurisdictions do limit the amount to a specific percentage of landings. Massachusetts also requires reporting for bycatch that is retained, but reporting catch discarded at sea is not required. Thus, bycatch rates can be variable depending on location but are generally believed to be low.
The most common bycatch species are knobbed whelks, channeled whelks, redbeard and sulfur sponges, and quahogs.
The bay scallop fishery is small-scale, so management techniques that require only minimal monitoring, seasonal fishery opening, local eelgrass protections, are appropriate. Expectedly effective measures are in place to protect breeding stock. It is unlikely that the fishery is having a serious negative impact on retained populations. However, more scientific information such as quantitative stock assessments and associated biomass targets) is needed to determine when management may need to change and how quickly.
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.
|AIS Aqua Foods, Inc.||United States||New Mexico|
|Aqua Star||United States||Washington|
|Bristol Seafood||United States||Maine|
|Codfathers Seafood Market||Canada||British Columbia|
|Conchyliculture Gloucester Shellfish Co. Inc.||Canada||New Brunswick|
|Frobisher International Enterprise Ltd.||Canada||British Columbia|
|Intercity Packers Meat & Seafood||Canada||British Columbia|
|John Nagle Co.||United States||Massachusetts|
|Kingsun Foods Co., Ltd||China||Liaoning Sheng|
|L&L International Inc.||United States||California|
|Lotus Seafood Inc.||United States||California|
|Lusamerica Foods||United States, United States, United States||California|
|Mariner Neptune||United States||Iowa|
|McRoberts Sales Co., Inc.||United States, United States||Florida|
|Northern Wind, Inc.||United States||Massachusetts|
|OM Seafood Company||United States||Oregon|
|Pacific Harvest Seafoods||United States||California|
|Profish Ltd.||United States||District of Columbia|
|Red's Best||United States||Massachusetts|
|Royal Hawaiian Seafood||United States||California|
|Sammy's Seafood Inc||United States||Florida|
|Santa Monica Seafood, Inc.||United States||California|
|Sea to Table, USA||United States||New York|
|SHS, LLC.||United States||Colorado|
|Star Fisheries Inc.||United States||California|
|Stavis Seafoods||United States||Massachusetts|
|The Fish Guys Inc.||United States||Minnesota|
|The Hadley Company||United States||Massachusetts|
|Thimble Island Ocean Farm||United States||Connecticut|
|ZF America||United States||Washington|
- Environmental Defense Fund
- NOAA Fisheries
- Seafood Watch Program