Opinion article* written for The Newcastle Herald by Associate Professor Natalie Moltschaniwskyj, from the School of Environmental and Life Sciences, at the University of Newcastle.

Marine species around Australia are starting to change their marine postcodes as coastal waters become warmer. 

Tasmanians are already seeing new marine species becoming regulars in their backyard because the marine environment is changing.

The East Australian Current (EAC) is a major current that moves tropical waters southwards along the east coast of Australia.

The CSIRO predicts that climate change will “intensify the EAC”, which means it is moving further south and for longer than it has previously.

Marine organisms prefer to live in specific places or environments, and water temperature is important in determining where they can live.

So for marine species, whose current homes are becoming too warm, southern waters provide the conditions that they prefer; so moving home is a logical thing to do.

Some marine species will not be able to adapt or move and will die, particularly at the northern end of their range, because changes in water temperature will occur there sooner.

Kelp habitats, which dominate the temperate coasts of NSW, may disappear from the northern reefs and their loss will have an impact on all the marine fish and invertebrates that rely on them for food and shelter.

Scientists at the Australian Institute of Marine Science have identified that coral reefs of the Great Barrier Reef are already being affected by climate change.

Like the Great Barrier Reef, the stony corals (scleractinian corals) of the Solitary Islands and Lord Howe are vulnerable to bleaching  and coral disease associated with increased water temperatures.

This will lead to a loss of biodiversity and widespread changes in the composition of coral reef communities.

Marine species that do adapt to the warmer conditions will find that they are sharing their postcode with new neighbours;mobile marine species from further north that are searching for cooler water. 

Old and new species will compete for space and food, and the old may have new predators. The rules that determine  biodiversity on our coastline will change.

Scientists are finding it hard to predict exactly what the species communities will look like in the changing marine environment.

Important aquaculture species, such as oysters and salmon, will be affected by increasing water temperatures. Industry and scientists are working together to examine the ways that the aquaculture industry can adapt to the impact of climate change.

Some oysters may be able to tolerate warmer temperatures and their offspring will survive changes in the marine environment and allow the aquaculture industry to continue production of oysters. Scientists are also developing new feeds for salmon that will allow them to survive and grow faster in warmer waters.

New species arriving on our coastline will have a number of positive and negative impacts.

Species that are good for eating will open new fishing opportunities for commercial and recreational fishers. For example, it is possible that coral trout, Plectropomus leopardus, will be caught regularly by recreational fishers and could  become abundant enough to support small scale commercial fisheries.

However, there is the possibility that some of marine organisms heading south will include harmful species, such as venomous jellyfish.

The marine environment along the central and southern coasts of Australia is special because most species are unique and cannot be re-introduced if they go extinct.

In Tasmania there is nowhere to move further south, the next stop is Antarctica. These species cannot move home.

It is critical that we become aware sooner rather than later about changes occurring in our marine environment. Fishers, divers and beachcombers are the first to see changes and scientists need to record their observations and capture their knowledge.

Redmap is a unique citizen science project (redmap.org.au) that invites everyone to record information about marine species they do not usually see.

Expert scientists verify the sighting and the information is tracked and analysed. Knowledge generated from the data is communicated to the community, environmental managers and policy makers to allow us to adapt proactively to these changes.

As our marine environment changes due to climate change, there is little doubt that the marine community and the biodiversity that we have been used to seeing will be different in the future.

For more information and to help go to www.redmap.org.au

* Opinion pieces represent the author’s views.