Common Name	Manila Clams	Conservation Notes
Scientific Name	Venerupis/Tapes phillippinarum	Sustainability Ratings/Certifications
Market Names	Littleneck Clams	Buying Tips
Sushi Name	N/A	Health/Nutrition

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MANILA CLAMS MARKET ALERT - updated September 2011

All is calm on the clam front.  The market for Manilas, the most popular species consumed by restaurants on the West Coast, has been relatively stable as supplies are meeting adequate market demand.  U.S. production of Manilas, most of which are farm-raised in the inland waters of Washington state, has been relatively stable at about 500 metric tons (meat weight) for some time, although production slumped to 425 metric tons of meats last year.
Growers in Puget Sound site ongoing issues with leaky septic tanks as their main impediment to increased production, as periodic closures have hampered their ability to harvest more clams, they say.

Prices for Manilas have eased slightly, as imports of similar-sized frozen whole clams from China continue to grow sharply. Through July, U.S. imports of frozen clams from China were up 60% to a whopping 5,500 metric tons. With an average imported price of about $1/lb. , the Chinese clams are substantially less than live Manilas which have been selling to restaurants for about $2.25/lb.

Conservation Notes

Inherent Operational Risks/Risk of Pollution and Habitat Impacts: Clam farms are usually located in protected beaches, inlets, and estuaries that have been registered with a shellfish authority. On the U.S. Pacific coast, Manila clams are farmed from cultured beds that have received a national permit through the U.S. Army Corps of Engineers. In British Columbia, Manila clams are cultured and harvested from wild beds by hand.

Use of Marine Resources/Feed: Shellfish are filterfeeders so they generally don’t require additional feed beyond seawater. Some farmers may add some algae as feed but clams can actually lower the levels of nitrogen, phosphorous, and other particles in water, effectively cleaning it. As a result, no controls are necessary for effluent from Manila clam farming operations, according to the Blue Ocean Institute.

Management Effectiveness: Water quality is monitored by a national shellfish sanitation program. Manila clam aquaculture production is well-managed, according to the Monterey Bay Aquarium.

Ecological Effects: Although the species is native to Japan, Manila clams have been farmed along the Pacific coast of U.S. and Canada since the 1930s so there are no negative impacts on native ecosystems, according to the Blue Ocean Institute. Manila clams are farmed at high densities, but these volumes do not surpass what the beaches can handle. However, outside pollution and contamination from bacteria as well as brown tides have forced beach closures, causing farms to close as well. The mesh netting used to deter predators is not considered harmful. Manila clams are usually collected with tongs, rakes, and handheld dredges that don’t harm the seafloor the way large hydraulic dredges used for collecting other clams can, according to the Seafood Choices Alliance and the Monterey Bay Aquarium.

Sustainability Ratings and Certifications

	Seafood Watch	SeaChoice	FishWise	Blue Ocean Institute	New England Aquarium	Marine Stewardship Council
U.S. & Canada Farmed	Best Choice	Best Choice	Best Choice	Green	A List
International Farmed	Best Choice

Rating Explanation

Seafood Watch has ratings for farmed manila clams is worldwide. Blue Ocean Institute's rating for manila clams covers the U.S. and Canada.

Buying Tips

• Manila clams are generally sold live year-round, although some quantities may be frozen whole
• These small clams tend to be soft and sweet in taste
• Buyers generally recommend avoiding buying clams by the bushel, a common measure used on the East Coast, because the definition of a bushel can vary among suppliers
• If buying by the bushel, check to make sure that the shipments are what was paid for
• The best Manila clam shelf life and meat yield is in the winter time, which coincides with reduced prices due to lower demand from coastal resorts, according to some buyers
• After the clams spawn in the summer, shelf life drops off

Nutrition and Health

 *Paralytic Shellfish Poisoning (PSP) comes from eating clams that are contamined with toxic algae, also known as "red tide" from the color associated with the algal blooms.

Acknowledgements

• Seafood Watch by Monterey Bay Aquarium
• Blue Ocean Institute
• SeaChoice
• Seafood Choices Alliance
• Environmental Defense Fund