Colourful tropical sea slugs are being found further south in Australia as the climate warms, scientists says.

Steve Smith, the director of the National Marine Science Centre at Coffs Harbour in northern New South Wales, says the slugs are now being found up to 1,300 kilometres south of their known range.

“We’re very confident about that because these are such colourful organisms that they’re always seen by divers if they’re around,” he told the ABC.

“We know there’s been a documented increase in global seawater temperatures [and] we’re seeing changes in oceanographic conditions in different parts of the world.”

The ecological consequences were so far unknown, he told the broadcaster. The migration of sea slugs was not necessarily the “canary in the coal mine” but was an indicator of warming ocean temperatures.

“Because they have this capacity to be very useful indicators of environmental condition, we’re currently putting together a program which works with volunteers to document the distribution of these species,” he was quoted as saying.

“So, we can use them as a monitoring tool for climate change and any other environmental change.”