LOSING NEMO TO CLIMATE CHANGE

Finding Nemo is getting harder as Climate Change is making clownfish infertile.

The homes of the clownfish that inspired the hit movie are being destroyed by warming seas in the South Pacific.

It’s stressing the colourful creatures out and reducing their sex drive, decimating numbers of offspring by three quarters.

Closely related to corals, sea anemones are invertebrate marine creatures that live in symbiosis with algae, which provide them with food, oxygen and color.

Clownfish, also known as anemone fish, in turn use the structures as shelter to lay their eggs and raise their young—keeping the anemones clean in return.

The most recent research began when an ocean heat wave washed across French Polynesia in 2015 and 2016. A team of scientists tracked 30 different species of anemones in a lagoon off the island of Moore. That warmth didn’t just cripple corals. For more than four months, it attacked and bleached roughly half of those sea anemones. So scientists sampled the fish living among these overheated anemones and compared them with fish living in healthy ones nearby.

The release of hormones is known to affect how everything from sea birds to marine iguanas weather the rapid upheaval associated with climate change. That’s true for fish, too.

So will Nemo be left homeless?

In April 2016, elevated water temperatures also caused mass bleaching of corals and anemones off north-west Australia, including Christmas Island. Bleached anemones have also recently been reported elsewhere in the Pacific Ocean, Indian Ocean and in the Red Sea.

The future of the bleached anemones and their resident anemone fish will depend on how quickly the water temperature returns to normal. If the temperature decreases swiftly, bleached anemones can regain their colour and survive.

However, the frequency and intensity of bleaching events are predicted to increase as the climate changes. Consequently, there are serious concerns about the ability of anemones and anemone fish to cope with rising water temperatures.

Reducing global greenhouse gas emissions will limit subsequent bleaching events and help ensure the future of Nemo and its relatives.

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