SEA STARS OF THE PACIFIC NORTHWEST MOTTLED STAR Evasterias troschelii

Class Asteroidea

Order Forcipulatida

Family Asteriidae

MOTTLED STAR

Evasterias troschelii (Stimpson, 1862)

Identification:

5 long tapering arms. Aboral surface coarse. Colour extremely variable: mottled green, brown, grey, orange or reddish with white spines and rarely, blue. To 80 cm (31 in) across (a very large specimen in Victoria Harbour, BC).

Range:

Kamchatka and Pribilof Islands to central California; intertidal to 75 m (250 ft).

The MOTTLED STAR is extremely variable in colour. This specimen is typical in terms of its arm length relative to the size of the disc. Note the pattern of blunt, white spines.

This specimen is more brown.

Another brownish specimen with distinctive spines.

A mottled brown specimen with spines from Sechelt Inlet, BC.

An orange specimen from Sechelt Inlet, BC.

This form of the MOTTLED STAR (from Howe Sound, BC) has numerous small spines in a net-like pattern and does not seem to be as common as the large-spined form.

A juvenile specimen of the large-spined form only 5 cm (2 in) across.

An extreme example of sea star regeneration. This MOTTLED STAR is regenerating four new arms from the intact disc and single arm.

In April, 2004, I found tens of thousands of juveniles in shallow water near the head of Salmon Inlet, BC. They formed a thick layer over the rocky reefs.

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Notes:

Very common. It seems to have a greater tolerance of brackish conditions and usually replaces the PURPLE STAR in shallow habitats toward the head of BC mainland fjords. Varied diet includes mussels and other bivalves, barnacles, tunicates, chitons, snails and lamp shells. Like the PURPLE STAR, some males are host to an internal parasite that prevents sperm production. Spawning occurs from April to June.