Saturday, February 26, 2011
February 26, 2011 : Bloodworm
The genus Glycera is a group of polychaetes (bristle worms) commonly known as blood worms. They are typically found on the bottom of shallow marine waters, and some species (e.g. the common blood worm, Glycera dibranchiata), are extensively harvested along the Northeastern coast of the United States for use as bait in fishing. Another common species is the tufted gilled bloodworm, G. americana.
Bloodworms have a creamy pink color, as their pale skin allows their red body fluids that contain hemoglobin to show through. This is the origin of the name "bloodworm". At the 'head', bloodworms have four small antennae and small fleshy projections called parapodia running down their bodies. Bloodworms can grow up to 35 centimetres (14 in) in length.
Bloodworms are poor swimmers but good burrowers, living on the sandy or silty bottoms of the intertidal or subtidal regions. Though usually marine, they can tolerate low salt levels in the water, and also poor oxygen levels. Bloodworms and all water worms have adapted to life in the sand and silt for the protection it offers.
Bloodworms are carnivorous. They feed by extending a large proboscis that bears four hollow jaws. The jaws are connected to glands that supply poison which they use to kill their prey, and their bite is painful even to a human. They are preyed on by other worms, by bottom-feeding fish and crustaceans, and by gulls.