The photos below are predators of soft-shell clams that are most common along the shores in downeast Maine.
The northern moonsnail, Euspira heros.
Typical damage that the drilling moonsnail inflicts on its soft-shell clam prey. The hole is beveled, or countersunk.
These juvenile clams were attacked by moonsnails at a mudflat in north Lubec in 2008. A brief report explains results of a short-term experiment.
Green crabs, Carcinus maenas, are perhaps the most ubiquitous clam predators along the Maine coast. They are an invasive, or exotic, species with origins of the British Isles. They arrived in Maine in the early 1900's, and in eastern Maine during the early 1950's.
The damage observed here is presumed to be from green crabs. This is typical of crustacean predators such as crabs or lobsters.
These pits in the surface of a flat in Jonesport in 2006 are typical of those created by green crabs preying of soft-shell clams.
Here is a link to a presentation given by Dr. Brian Beal on September 24, 2014 in Portland, Maine at the Friends of Casco Bay's Casco Bay Is At Risk Forum. The entire presentation is 17 minutes and 41 seconds.