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Fish scientist Letizia Pessina is pursuing a cleaner wrasse, a super-smart fish resembling a striped tube of toothpaste that has wriggled to life.

Decked out in scuba gear and a pink bandana, she somersaults over a boulder coral, trying to snatch the elusive wrasse with a handheld aquarium net.

It’s taxing work in the 29.7-degree water. After a dive, Pessina and her fish-catching assistants often collapse in their yellow research dinghy for a nap.

Researchers catch, tattoo and release cleaner wrasse fish on Lizard Island as part of a behavioural research project.Credit: Janie Barrett

We’re in the waters off Lizard Island Research Station, a globally renowned facility that coral biologists Dr Emily Howells and her partner, Dr David Abrego, have just inherited as new co-directors. Another consecutive wave of coral bleaching has swept through reefs here and on the other side of the continent on Ningaloo.

After we watch Pessina’s thrilling wrasse chase, the scientists show me a line of three table corals, each responding differently to the abnormally hot ocean water.

One table coral is healthy, one is “fluorescing” with a sickly pink glow under stress, and another is bleached. Could the polyps surviving in abnormally warm waters hold the key to buying more time for Australia’s most spectacular natural asset?

That’s a controversial question.

Dr David Abrego and Dr Emily Howells, the new directors of Lizard Island Research Station, swim over a healthy (left), stressed (middle) and bleached (white) table coral.Credit: Janie Barrett

Marine ecologist Dr........

© The Sydney Morning Herald