A Port Phillip Bay Pest — Northern Pacific Starfish

    Northern Pacific Seastar

    Scientific Name: Asterias amurensis

    • Has five arms with pointed upturned tips
    • Yellow with purple detail
    • Distinct purple tips (like painted finger nails)
    • Arms are covered in many spines with jagged ends that are arranged irregularly along arm

    The Northern Pacific Seastar is a Port Phillip Bay pest.

    It was first confirmed in Victoria in August 1995 when the first adult Northern Pacific Seastar was caught off Point Cook. It was probably introduced into Australia through ballast water from Japan. This starfish has detrimental effects on native marine organisms, mainly because they are voracious predators that eat a wide range of native marine life. They can have a major impact on populations of native shellfish, which are important components of the Port Phillip marine food chain.They have been recorded feeding on a variety of native animals including shellfish (bivalve and gastropod molluscs, barnacles, crabs, other crustaceans), worms, sea urchins, other seastars. Spawning occurs during winter when water temperatures are around 10 to 12°C. Females are capable of producing up to 20 million eggs each. Once alternative food sources have been exhausted they can become cannibalistic.

    If you find one (or more) of these pests and you are positive that it is a Northern Pacific Seastar, remove it from the water. Please be careful: the Zig Zag Seastar is similar with five legs, brownish-yellow in colour with mauve tinges. Fortunately it does not have the brightly painted "nails" and its tips are blunt.