Australian Institute of Marine Science researchers studying the sexual chemistry that triggers coral to spawn on the Great Barrier Reef have found some early risers.

Principle research scientist Dr Andrew Heyward said the mass coral spawning was not expected until the next full moon in November but sexual activity had started with a few species after the October full moon, which augered well for a spectacular x-rated natural phenomenon next month.

AIMS research into coral biology challenges the theory of a single major mass spawning event which is typically in November after the full moon.

"It seems that for some species, in particular locations and in certain years, conditions suit them to mature their gametes a little ahead of or behind the main pack, said Dr Heyward.

He said the resulting coral larvae from the early spawners would already be drifting with the currents in search of a place to call home" Dr Heyward said.

The research at AIMS has found that natural chemicals on the reef have a key role in this process of new coral settlement and meamorphosis into growing colonies.

Dr Heyward and AIMS eco-chemist Dr Andrew Negri have been investigating what controls spawning and the presence of reef arousal cues, together with the reef flavours and scents that signal to coral larvae the places to settle and grow.

"So far we have isolated compounds from the reef that induce coral larvae to settle and have been using these in tests to show how pollution may affect coral recruitment on reefs.  We have also discovered microbial communities that enhance recruitment," said Dr Negri.

"It is helping us to understand how the reef coral communities survive over the long haul, how resilient it is to disturbance and how these processes can assist in remediation after damage," he said.

Most of the spawning and eco-chemistry research has been conducted on the Great Barrier Reef, particularly Lizard Island in the north and Magnetic Island off the coast of Townsville, together with several years of work at Ningaloo Reef in Western Australia.

The researchers are now linking in to a global program of scientific collaboration, where there is strong interest in understanding the annual cycles of coral reproduction, recruitment and options for reef restoration and conservation that rely on this vital stage in corals life history.