Identifying bivalve shellfish

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• Clams
• Mussels
• Oysters
• Scallops

Clams

Species of harvested clams include the following.

Arctic wedge clam (Mesodesma arctatum)

• Maximum length: 4 cm
• Colour: greyish-white
• Shape: wedge
• Location: Atlantic coast
• Habitat: continental shelf waters to depths of 90 m
• Note: this clam is unique because it doesn’t shrink once cooked

Atlantic surf clam (Spisula solidissima)

• Maximum length: 17.5 cm
• Colour: yellowish-white
• Shape: V-shaped
• Location: Atlantic coast
• Habitat: shallow holes in sand bars or ocean floor to water depth of 75 m
• Note: also known as a bar clam

Butter clam (Saxidomus gigantea)

• Maximum length: 13 cm
• Colour: yellow or greyish-white
• Shape: square or oval
• Location: Pacific coast
• Habitat: holes under tidal beach or ocean floor to water depth of 15 m
• Note: stays on a single beach for life

Geoduck clam (Panopea generosa)

• Maximum length: the shell is 20 cm
• Colour: the shell is white and the neck is reddish-brown
• Shape: the shell is rectangular
• Location: Pacific coast
• Habitat: holes under tidal beach or ocean floor to water depth of 100 m
• Note: long neck

Littleneck clam (Protothaca stamineais)

• Maximum length: 7 cm
• Colour: white or grey with brown areas
• Shape: round
• Location: Pacific coast
• Habitat: holes under tidal beach or ocean floor to water depth of 12 m
• Note: rings on shell show the clam’s age

Manila clam (Venerupis philippinarum)

• Maximum length: 7.5 cm
• Colour: yellow, brown or grey
• Shape: oval
• Location: Pacific coast
• Habitat: shallow holes in tidal beach sand, gravel or mud
• Note: native to Japan, accidentally introduced to Canadian waters during the 1920s or 1930s

Quahaug (Arctica islandica)

• Maximum length: 13 cm
• Colour: yellowish-brown
• Shape: oval
• Location: Atlantic coast
• Habitat: holes under tidal beach or ocean floor to water depth of 250 m
• Note: among the slowest growing clams harvested commercially

Razor clam (Siliqua patula)

• Maximum length: 25 cm
• Colour: brown or olive green with a small purple area
• Shape: oval
• Location: Atlantic and Pacific coasts
• Habitat: holes under tidal beach or ocean floor to water depth of 20 m
• Note: shell has a sharp edge

Softshell clam (Mya arenaria)

• Maximum length: 9 cm
• Colour: milky white
• Shape: oval
• Location: Atlantic and Pacific coasts
• Habitat: holes under tidal beaches and ocean floor
• Note: top and bottom shells are different

Stimpson's surf clam (Mactromeris polynyma)

• Maximum length: 15 cm
• Colour: yellow or brown
• Shape: an oval or sometimes triangular shell
• Location: Atlantic, Pacific and Arctic coasts
• Habitat: holes under tidal beach or ocean floor to water depth of 100 m
• Note: difficult to distinguish from the Atlantic surf clam

Varnish clam (Nuttallia obscurata)

• Maximum length: can grow to 38 mm in about 4 years, but size and age at maturity aren't known
• Colour: shiny brown
• Shape: round
• Location: Pacific coast
• Habitat: intertidal zone of sand/gravel beaches, and often found in streams, freshwater runoff or groundwater seepage
• Note: also known as a savoury clam

Mussels

The following single species of mussel is harvested.

Blue mussel (Mytilus edulis)

• Maximum length: 10 cm
• Colour: bluish-black
• Shape: sides may be straight or curved
• Location: Atlantic and Pacific coasts
• Habitat: inshore waters
• Note: this species is farmed in the Maritimes

Oysters

Species of harvested oysters include the following.

American oyster (Crassostrea virginica)

• Maximum length: 15 cm
• Colour: reddish-brown or purple
• Shape: oval
• Location: Atlantic coast
• Habitat: brackish and salty waters from 2 to 10 m deep
• Note: this species is farmed on leased areas of seabed in the Maritimes

Olympia oyster (Ostrea conchaphila)

• Maximum length: 9 cm
• Colour: white to dark purple
• Shape: oval
• Location: Pacific coast
• Habitat: attached to rocks or hard ground in shallow water
• Note: found in saltwater coves and lagoons and is the only oyster native to the west coast of North America

Pacific oyster (Crassostrea gigas)

• Maximum length: 30 cm
• Colour: brown, green or grey
• Shape: fluted shell with a deep cup
• Location: Pacific coast
• Habitat: attached to hard surfaces in shallow water
• Note: rough shell with sculptured appearance

Scallops

Species of harvested scallops include the following.

Iceland scallop (Chlamys islandicus)

• Maximum length: 10 cm
• Colour: grey, reddish-brown or chalk white
• Shape: fan-shaped
• Location: Atlantic coast
• Habitat: offshore areas near Newfoundland at water depths of 50 m to 180 m
• Note: reddish-pink upper shell and white or cream-coloured lower shell

Sea scallop (Placopecten magellanicus)

• Maximum length: 20 cm
• Colour: reddish-brown and white
• Shape: fan-shaped
• Location: Atlantic coast
• Habitat: offshore areas including St. Pierre Bank off Newfoundland and Georges Bank off Nova Scotia
• Note: like all scallops, sea scallops have photoreceptive eyes along their edge

Pink scallops and spiny scallops (Chlamys rubida and C. hastata)

• Maximum length: 8 cm
• Colour: the spiny scallop is reddish-brown and the pink scallop is pinkish-white
• Shape: fan-shaped
• Location: Pacific coast
• Habitat: offshore areas to water depth of 200 m
• Note: while spiny and pink scallops are different species, they’re closely related