Post Diving and Marine Pests

After Diving and Marine Pests

Introduced marine pests are marine plants or animals that are not native to Australia but have been introduced by human activities.

Australia has over 250 introduced marine species. Most have relatively little impact on coastal ecosystems. However, introduced seastars, crabs, mussels and seaweeds have become marine pests in various locations throughout Australia and several have had significant impacts on marine ecosystems. For example, the Northern Pacific Seastar (Asterias amurensis) is a voracious feeder that preys on a wide range of native marine biota. In Tasmania's Derwent estuary they have become the dominant invertebrate predator having a major impact on populations of native shellfish that are important components of marine foodwebs. This species has also been directly implicated in the decline of the endangered Spotted Handfish (Brachionichthys hirsutus). It is suspected that the seastars prey on handfish egg masses, and/or on the ascidians which Spotted Handfish spawn on. Two years after first being detected in Victoria's Port Phillip Bay, Northern Pacific Seastar numbers were estimated to be 12 million individuals.

Introduced marine pests also compromise the public amenity of marine recreational activities, including fishing, scuba diving and boating. Their presence in coastal ecosystems threatens the viability of fishing and seafood industries and the growing eco-tourism sector.

One mechanism whereby marine pests can be introduced is when international ships discharge their ballast water in Australian coastal waters. The further spread can take place via recreational vessels, for example, when pests are attached to the hull or when gear or areas of the vessel are not cleaned and dried thoroughly. Microscopic spores of algae can remain viable for 1 – 2 days floating in water in the bilge or under deck areas.

NSW DPI also provides a 24hr recorded hotline where people can report: (02) 4916 3877 or visit DPI's website for more information.

What Can You Do?

• Remove all pieces of weed and fish from your boat or trailer
• Drain bilge, hulls, buckets and associated boating paraphernalia and let them dry
• Hose all gear and the boat and trailer with high-pressure fresh water
• If freshwater wash-down facilities are not available on-site, ensure all gear is washed well away from streams and watercourses (including stormwater drains) that may transport spores
• Wash dive gear thoroughly with freshwater, particularly if you visit an infected site