Resources

Gulf of Maine Library Collection

Identification of Important Habitats in the Lower Casco Bay (Maine) Watershed

Chapter 5. Shellfish, Marine Worm Habitats

GENERAL: A number of species of shellfish and marine worms are on the Gulf of Maine Council's Species List for Identifying Regionally Significant Habitats. Among the shellfish are softshell clams (Mya arenaria), blue mussels (Mytilus edulis), northern quahogs (Mercenaria mercenaria), and sea scallops (Placopecten magellanicus). Marine worms on that list include bloodworms (Glycera dibranchiata) and sandworms (Nereis virens). All species are of recreational and/or commercial importance, and also are important prey of other vertebrate and invertebrate marine wildlife.

SOURCES OF BIOLOGICAL AND SPATIAL DATA: The analysis relies on GIS coverages digitized by Seth Barker (DMR). These represent areas which have been commercially harvested; therefore, they do not portray all suitable habitats in Casco Bay. NOAA and FWS are in the process of modeling softshell clam habitat in Casco Bay; suitability of habitats will be based on salinity, temperature, substrate, and water depth.

MAPPING OF HABITATS: The shellfish coverage includes areas from the DMR shellfish coverage having any of the 4 species of bivalves listed above. The marine worm coverage includes all original marine worm polygons from the DMR worm coverage. The coverages are not intended to depict the limits of areas being managed or under regulatory control.

Grids were created from both of these coverages, and scores assigned to the habitats for use when combining coverages for all evaluation species. Because habitat quality could not be inferred from the data, all harvested areas were scored at an intermediate value (4 out of a possible 8, before adjustments).

Figure 6, shellfish harvest areas

Figure 7, marine worm harvest areas

To menu for file download

<RETURN TO TABLE OF CONTENTS>