BCS: A Major Player in the Global Theater of Marine Crustacean Disease

Tanner crabs (Chionoecetes bairdi). Photo by Vanessa Lowe.

Bitter Crab Syndrome (BCS) is a fatal disease of crustaceans that is caused by a parasitic dinoflagellate of the genus Hematodinium. To date nearly thirty species of crustaceans are known to be infected by Hematodinium spp. world-wide, and the large majority of parasitized hosts are located in the North Pacific and Atlantic Oceans.

Affected species include several commercially important decapod species such as the snow crab from the Gulf of Alaska, the Bering and Chukchi Seas, eastern Canada and Greenland; Tanner crab from Southeast Alaska, the Gulf of Alaska, and Bering Sea; the grooved Tanner crab from western Vancouver Island; the blue crab from the eastern U.S. seaboard and Gulf of Mexico; the Norway lobster from the North and Baltic Seas and North Atlantic Ocean; and the velvet and edible crabs from the North Atlantic Ocean.

The Alaska Fisheries Science Center’s Fisheries Resources Pathobiology program has been monitoring BCS in eastern Bering Sea snow and Tanner crabs since 1988. The program works to understand host-parasite interactions. These studies are important for understanding why one host may be susceptible to disease and another is not. This is particularly true for BCS. To this end, the program is developing molecular tools for identifying pathogens, with a long-term plan to develop other molecular tools that measure host adaptive responses and identify markers that determine pathogen virulence.