Introduced Species in aquatic ecosystems

A presentation on introduced and invasive species in aquatic ecosystems

1. Introduced Species – Threats to Aquatic Ecosystems

2. How are pests introduced into marine waterways in our country?

3. Ballast Water The Great Barrier Reef and waters around Australia are now facing a serious environmental threat from marine organisms brought in by foreign ships, especially in ballast water. Picked up overseas and then discharged in Australia, this water can bring unwelcome hitchhikers that poison shellfish, compete with native species, and cause serious environmental problems. At least 70 varieties of fish, worms, molluscs, seaweed, and toxic algae have been introduced to Australia in the ballast water or on the hull of ships – some of these have become pests

4. Ballast water Health checks have found some ballast water contains human diseases such as cholera Other ballast water contains toxic micro-organisms, such as dinoflagellates, which get into shellfish and then cause illness or even death in humans who eat affected oysters or abalone The Tasmanian shellfish industry lost millions of dollars after blooms of Gymnodinium catenatum algae shut down shellfish beds for months at a time Several fish species have been introduced in ballast water – they compete with native fish for food and some, like the large Japanese sea bass, eat native fish.

5. Introduced Species – Pest Fish Queensland has the highest diversity of freshwater fish in Australia Unfortunately, this diversity is threatened by the presence of exotic fish and turtles, which have successfully established in some of our waterways Some exotic fish pose such a threat to Queensland waters that they have been declared as ‘noxious’ in biosecurity legislation

6. Introduced Species – Aquatic Weeds Several exotic aquatic plant species are weeds and can cause much damage to our aquatic environments as well as hurting native plants and animals

7. Introduced Species – Marine Pests There are over 200 marine pests reported in Australian waters, most of which were introduced accidentally by shipping and aquaculture activities

8. Introduced Species – Marine Pests in QLD Waters White Colonial Sea Squirt There have been confirmed detections of white colonial sea squirt in the Gulf of Carpentaria, Townsville, Airlie Beach, Mackay and Brisbane They were introduced via fouling on ship hulls and possibly in ballast water, and can overgrow native species Predominantly found growing on submerged and floating man-made structures such as buoys, moorings, pontoons and boats It is not considered feasible to eradicate due to the pest’s high reproductive capacity and inability to effectively treat established populations or control its further spread

9. Introduced Species – White Colonial Sea Squirt

10. Introduced Species – Marine Pests in QLD Waters Black Scar Oyster There have been confirmed detections of black scar oyster in Cairns, Port Douglas and Cooktown A large rock oyster that is not easily distinguished from other tropical rock oysters The black scar oyster fouls submerged and floating infrastructure including pylons, pontons and boats with the ability to occupy disturbed habitats Little is known about the potential invasiveness and impacts

11. Introduced Species – Marine Pests in QLD Waters Choose one of the following pests that are already established in Australian waterways, and discuss what they are, where they originated from, how they got into our waterways, and their impact on our native species: Tilapia Aquarium Caulerpa Asian date or bag mussel Asian shore crab European fan worm European shore crab Japanese kelp New Zealand scr ew shell Northern Pacific seastar Soft shell or long-necked clam

12. Introduced Species – Marine Pests in QLD Waters Invasive pest species with the highest chance of arriving and establishing in QLD waters have been identified: Asian green mussel Black striped false mussel Asian bag mussel Brown mussel Harris mud crab Chinese mitten crab Japanese seaweed/wakame American slipper limpet Asian basket clam Asian paddle crab New Zealand green-lipped mussel Rapa or veined whelk