crabs

Researchers say most stingrays spend their time resting on the seafloor foraging for clams, marine worms, shrimp, isopods, crabs and small fish.

Take the copepod, a type of zooplankton that is a distant relative of crabs and lobsters.

Fishers said such escape holes were allowing octopus to enter, devour crabs and leave, resulting in empty pots and no catch for the day.

This type of shark mainly eat crabs and small crustaceans, marine biologist Dr Patrick Collins said.

Police said the hermit crabs were "a national treasure", being a part of Amami Island's plant and animal diversity.