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Northern Pacific seastar (Asterias amurensis)

This large, aggressive predator affects native species, including oysters, mussels and scallops. It can also affect commercial fishing and aquaculture.

Key facts

Type: Pest animal, invertebrate.

Native to: Northwest Pacific.

Established in: VIC, TAS.

Identification

  • Juveniles are yellow to orange with purple markings.
  • Adults are yellow.
  • It has five arms with pointed, upturned tips.
  • It can grow to 50 cm across.
  • Look-alike: Uniophora spp. have five arms with rounded, rather than pointed, tips and grow to 20 cm across.
  • Look-alike: Coscinasterias muricata has 7 to 14 arms, usually 11, with pointed but not upturned tips.

Where it lives

In Australia, it occurs in bays, estuaries, shores, shallow waters and reefs, and is established in Port Phillip Bay, Victoria, and along Tasmania’s east coast.

Why it matters

  • It is a large, aggressive predator of native species.
  • Affected native species include oysters, mussels and scallops.
  • It can affect commercial fishing and aquaculture.

How it spreads

  • Movement can occur via vessels, fisheries and aquaculture stock.

Control methods

  • If you see a suspected pest, report it to your state or territory authority, even if you are unsure.
  • Note the exact location and take a photo, including an object for scale if possible.

Site hygiene and welfare

  • Inspect and clean boats or yachts, including hard-to-reach areas, and treat the hull regularly.
  • Clean and dry fishing and diving gear after every use, and check aquaculture stock is free from pests.
  • Use methods set out in the national model codes of practice and standard operating procedures for the species.
  • Coordinate control with neighbours and the local government biosecurity plan, as isolated effort is quickly undone by reinvasion.

Classification by state

  • Australia (national): Priority marine pest. On the Australian Priority Marine Pest List, agreed by all governments as a marine pest of national concern.
  • Queensland: Prohibited matter. Report it to Biosecurity Queensland on 13 25 23 within 24 hours and do not move or deal with it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • Victoria: Noxious aquatic species. Declared a noxious aquatic species under the Fisheries Act 1995, so it must not be brought into Victoria, kept, sold, moved or released into waters. Report any sighting to the Victorian Fisheries Authority on 13 FISH (13 3474).
  • South Australia: Noxious species. Declared a noxious species under the Fisheries Management Act 2007, so it must not be brought into South Australia, kept, sold or released, and it must not be returned to the water alive. Report any sighting to PIRSA FISHWATCH on 1800 065 522.
  • Western Australia: Noxious fish. Prescribed as a noxious fish under the Fish Resources Management Regulations 1995, so it must not be brought into WA, kept, sold or released. Report any sighting to FishWatch on 1800 815 507.
  • Tasmania: Declared pest. It is a declared pest under the Biosecurity Act 2019 (Tas). Report sightings to Biosecurity Tasmania and follow any management requirements.
  • Northern Territory: Not a declared pest. Not on an NT declared or prohibited list. Check with the NT Government before keeping, moving or releasing it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources