Hooked mussel
Ischadium recurvum

The hooked mussel is a bivalve whose dark, ridged shell is strongly curved, or “hooked” on one end. It is prolific in oyster reefs—often “wrapping up” oysters—and can outnumber the amount of oysters by several fold.

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More than a dozen hooked mussels are attached to a triangular hunk of stone, which has been lifted out of the water and set down in the bright sun.
Hooked mussels colonize hard surfaces similar to oysters, such as an artificial stone ribbon reef at Hail Cove, part of a living shoreline designed to slow the rate of erosion at Eastern Neck National Wildlife Refuge in Kent County, Md., on June 26, 2014. (Photo by Jenna Valente/Chesapeake Bay Program)

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Appearance

The hooked mussel is small, generally reaching one to two inches long. Its shell surface has distinct ridges and curves, and has a dull-colored black or gray exterior with a shiny purple or rosy brown interior. The front end of its shell is strongly curved, or “hooked.”

Feeding

Hooked mussels are filter feeders that open their shells during high tide, drawing in water and filter food particles over their gills.

Predators

Predators of hooked mussels are primarily seaducks, such as scoters and goldeneye.

Reproduction and life cycle

As hooked mussels reach sexual maturity, their mantle will turn either bright yellow or stippled brown in color. Spawning occurs from June to October. Free-swimming larvae drift in the water for a few months, eventually anchoring themselves on hard surfaces as they mature into adults.

Did you know?

  • Research suggests that hooked mussels can more than double the overall filtration capacity of an oyster reef. Hooked mussels also filter picoplankton, the smallest type of marine plankton, twice as effectively as oysters.
  • Hooked mussels can actually move by pulling themselves along on their byssus threads—releasing some and reattaching others—although this is a very slow process and they do not move very far.

Sources and additional information

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