Scientists are on a mission to save Nemo

SCIENTISTS are warning Finding Nemo could have a much darker sequel as artificial lights threaten to wipe out the clownfish species.

The famous orange reef fish found throughout the Great Barrier Reef could be under threat from artificial lights.

A new Flinders University and the University of Melbourne study published in Biology Letters has found exposure to LED lights at night severely impact the clownfish reproductive cycle.

Co-author Professor Stephen Swearer from the University of Melbourne's School of BioSciences said light played a huge impact on the breeding patterns of the clownfish.

Prof Swearer said clownfish tended to spawn around the time of a the full moon, with their eggs usually hatching a few hours after dusk.

 

Anemone and clownfish.
Anemone and clownfish. Mike McKinnon

But the report's lead author and research associate in biodiversity and conservation Dr Emily Fobert said artificial lights could destroy this delicate breeding process.

The experiment, using 10 breeding pairs of clownfish, showed an increasing amount of artificial light at night in coral reefs, even at relatively low levels, masked the natural cues that triggered clownfish eggs to hatch after dusk.

While the eggs not exposed to artificial light hatched normally, Dr Fobert said the test eggs incubated in the presence of an artificial LED were devastated.

She said under artificial lights the eggs had a zero success rate of hatching, with no offspring surviving as a result.

"So the presence of light is clearly interfering with an environmental cue that initiates hatching in clownfish," Dr Fobert said.

With many similar lights commercially available and widely used near coral reefs, she said the reproductive fitness of reef fish could be severely impacted by their human neighbours.

Clown fish could be under threat from artificial light.
Clown fish could be under threat from artificial light.

An increasing number of housing developments, promenades, ports, harbours and dockyards are exposing reef environments to penetrating LED lights, she said.

She was concerned tourists attractions like floating accommodation and over-water bungalows including glass floors that shone lights directly on the reefs below so guests could see the fish at night.

The intensity of the artificial light exposure could severely impact, not only the future of the iconic orange fish, but of many other species on the reef, Dr Forbert said.

With many other reef fish sharing similar reproductive behaviours she said "The overwhelming finding is that artificial light pollution can have a devastating effect on reproductive success of coral reef fish,"

Senior author and founder of the Saving Nemo Conservation Fund, Karen Burke da Silva said an improved understanding about the impact of artificial light on coral reefs could develop solutions for stressed ecosystems.

"Artificial light at night is becoming a greater concern among ecologists, as light is spreading globally, and the impacts on organisms can be severe," Prof Burke da Silva said.

She advocated for more research to investigate the impacts of artificial lights on the marine environment.


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