Asterias amurensis: Is this the marine pest experts fear most?

Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish © Julianne Stuart, Australia

Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish © Julianne Stuart, Australia

Asterias amurensis, or the Northern Pacific seastar is a huge starfish (up to 50cm in diameter) that is described by the Ministry for Primary Industries as an eating machine and its favourite food includes mussels, clams, scallops and other shellfish.

The Northern Pacific seastar has 5-pointed arms with upturned tips and yellow and purple markings. It is a species that can travel undetected on boat hulls or in ballast water. It grows up to 24cm across but can reach 50cm.

It often groups together in large numbers.

In short, it could decimate our native biodiversity. It is one of five species focused on by the National Marine High Risk Site Surveillance program and the good news is that it’s not been detected in New Zealand yet - but its impact should it ever make it here, would almost certainly be devastating, as it has been in locations where it’s established in Tasmania and Victoria.

One community group in Hobart estimates it has removed more than 200,000 sea stars from its local waters, and another group in Victoria removed more than 60,000 specimens of this invasive pest between February and June this year.

If you see something that looks like a Northern Pacific seastar, please take a photo or collect a sample, record the location and report it urgently to the Ministry for Primary Industries 0800 80 99 66 or via the online form at Biosecurity New Zealand // Online Notifications (mpi.govt.nz)

1. Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia

2. Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia

3. Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia

4, Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia

5. Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia

6. Northern Pacific seastar is a huge starfish (up to 50cm in diameter) - it is an eating machine and its favourite food includes mussels, clams, scallops and other shellfish - photo © Julianne Stuart, Australia