European Green Crab (Carcinus maenas)

The Green Crab is a small shore crab found in shallow water, generally in sheltered areas. They appeared in the 1950s in the bay of Fundy, probably after moving up the infested coast of northeastern united states. They are common in salt marshes, on sandy beaches, and on rocky coasts, and they can tolerate a wide range of salinities. In adult green crabs their carapace can reach up to 10cm but are usually less than 8cm. They range from mottled, green, red, yellow, to brown in coloration. They have serrated shells with five spines on either side of the eyes and three between the eyes. Their back legs are pointed, slightly flattened, and hairy.

Green crabs are voracious consumers of both plants and animals, especially soft-shelled clams, oysters, quahogs, and mussels. They destroy beds of bivalves and uproot Eel grass, an important habitat-forming species for native fish, invertebrates, and waterfowl. They also outcompete native crab species for resources such as food and space. These behaviours all result in a negative impact on biodiversity and harm local fisheries. They have been given the nickname cockroaches of the sea.

Green Crabs are thought to spread mostly during their larval stage where they are moved about in ballast water transfers or drifting on ocean currents. Their larval stage can last up to 90 days. Adult Green Crabs can survive for a long time in fresh water and out of the water. They can also be introduced if fishing gear is moved to a new area or if crabs are intentionally discarded with bycatch outside of their catch area.

Always remember to clean, drain, dry your boat before entering a new body of water to prevent the spread of green crabs. If Green Crabs are caught as by-catch do not release them.

Lähettänyt jgilice1 jgilice1, 30. marraskuuta 2021 19:30

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