Capitellid Worm

Heteromastus filiformis is a long thin bright red worm. The animal is filled with hemoglobin, the same pigment which colors our blood red. We use hemoglobin to carry oxygen. The worm uses it for the same reason. This allows the worm to live in parts of the mudflats where there is very little oxygen. The worm burrows itself into a vertical tunnel, head first. It eats up sand containing bacteria, its main diet. The digested sand is excreted onto the flats and looks like black-gray pills.

Polychaeta larva, whose adults are not listed before, found in plankton samples

This bristle worm has a thin (1 mm) and relatively long body (100 mm). Two regions can be distinguished across the body: an anterior end with twelve bristle-covered segments and a posterior end with segments with thickened parapodial grooves. The anterior end is coloured red, the posterior end reddish green or yellow.

southern Gaspe waters (Baie des Chaleurs, Gaspe Bay to American, Orphan and Bradelle banks; eastern boundary: eastern Bradelle Valley), lower St. Lawrence estuary; Prince Edward Island (from the northern tip of Miscou Island, N.B. to Cape Breton Island south of Cheticamp, including the Northumberland Strait and Georges Bay to the Canso Strait causeway); Cobscook Bay

In both sampling periods the distribution area of Heteromastus filiformis was mainly limited to the coastal zone. The highest numbers were observed here as well (up to maximum 450 ind./m2). Contrary to the 1994-2001 period, the species had a higher frequency of occurrence in the eastern coastal zone in the 1976-1986 period. The density levels for this species at other locations (Flemish Banks and Zeeland Banks) were rather low.

bathyal, infralittoral and circalittoral of the Gulf and estuary

Heteromastus filiformis has a clear preference for fine sediments. The species has a high relative occurrence (> 20%) in sediments with a median grain size of 100-200 µm. In addition, the species tends to prefer sediments with high mud contents: although the relative occurrence follows an erratic pattern, the species occurs more frequently as the mud content increases.