Northern Pacific Sea Star

Asterias amurensis

If this seastar arrives in New Zealand it could have a serious impact on our aquaculture industry and our marine environment generally. The Northern Pacific Seastar is currently found in huge numbers in two areas of Australia (Derwent Estuary in Tasmania and Port Philip Bay, Melbourne).

It feeds on wild and farmed shellfish and a wide variety of other marine animals. It is normally found in shallow water but can be found from the intertidal area through to the subtidal as deep as 200 m. It can be found on muddy, sandy, pebbly seabeds as well as on rocks and man-made surfaces, even mussel lines. You would not normally see it in areas with high wave action.

Mode of distribution

Northern Pacific Sea Star Northern Pacific Seastars could reach New Zealand in ships’ ballast tanks (as the free swimming larvae) in ships’ water intakes or among other marine fouling on the outside of ship or yacht hulls particularly around the propeller or rudder area.

Description

Key features: Northern Pacific Seastar has five arms which have pointed and often up-turned tips. The arms join onto a central disc and are covered by clumps of small chisel-like spines.

Size: 10 cm diameter, individual arm length can be 40-60 mm.

Colour: Yellow and/or purple to red.

Topside: Arms covered with numerous unevenly arranged small spines with jagged ends.

Nothern Pacific Sea Star Underside: On each arm the spines are in a single line either side of the groove where tube feet lie.