Northern Pacific seastar

What does it look like?

The Northern Pacific seastar has five arms with pointed, often up turned tips. The arms join a central disc and are covered in clumps of small, chisel like spines. It can grow up to 50 cm across and ranges in colour from yellow and purple to red.

The arms are covered with many unevenly arranged small spines with jagged ends. There is also a single line of spines on either side of the groove where the tube feet lie

Why is it a problem?

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.

Control methods

You must notify us or the Ministry for Primary Industries if you suspect the presence of this organism.

You can help prevent the spread of marine pests by:

• Regularly cleaning your boat’s hull –keep fouling growth to no more than a light slime layer.
• Applying a thorough coating of antifouling paint and keep it in good condition.
• Ensure your hull is clean and free of fouling before you travel to a new area.
• Clean and dry any marine equipment (e.g. ropes, lines and pots) before using in a new area.
• Inspect areas on your boat that retain water for signs of marine life.
• Check for aquatic weeds tangled around anchors, trailers and other equipment.

Related links

• Ministry for Primary Industries
• New Zealand Marine Pest ID Guide
• Unwanted Organisms Register
• MPI listing for Northern Pacific seastar