Technology

Record season for captive-bred weedy sea dragons

In the watery world of the weedy sea dragon, it's the males who carry the young before they hatch.

For up to two months, Dad incubates the eggs on the underside of his tail. Not one or two eggs, mind. Rather, dozens gather together like tightly packed pomegranate seeds.

Senior assistant aquarist Simon Claridge gets a close-up look at the juvenile weedy sea dragons.
Senior assistant aquarist Simon Claridge gets a close-up look at the juvenile weedy sea dragons. Photo: Jason South

For weeks, staff at the Sea Life Melbourne Aquarium watched as their wild male carried his offspring. His tail broadened to accommodate the eggs, which had been laid by a captive female introduced to him for the first time last spring.

He had staff, including senior assistant aquarist Simon Claridge and curator Paul Hale, holding their collective breath. Not since 2011 had there been a successful breeding season for the weedy sea dragon. This pairing would also mark the first time the combination of a wild male and captive female had produced young - or fry.

Two of the weedy sea dragon fry with senior assistant aquarist Simon Claridge.
Two of the weedy sea dragon fry with senior assistant aquarist Simon Claridge. Photo: Jason South

In early December the eggs started to hatch and the aquarium's weedy sea dragon population ballooned.

Three months on and 45 fry are still going strong - an outcome which represents a 95 per cent survival rate. It's almost unheard of for captive-bred young.

Advertisement

Mr Hale said the fry were destined for big things. The aquarium has relationships with aquariums in the United States, China, Europe and the United Kingdom.

When they are ready to travel, the weedy sea dragons will go to aquariums as part of captive breeding and education programs to raise awareness of the shy creature.

"We expect the dragons to go over to several continents," Mr Hale said.

Only found in southern Australian waters, weedy sea dragons are listed as near threatened internationally and are Victoria's marine emblem. The weedy sea dragon lives for up to nine years.

Mr Hale said the successful breeding season was the result of many hours of observing the creatures in the wild and trying to replicate the conditions in captivity. He said changes to the light, water temperature and water flow proved to be key.

"There is still a lot more to learn on and improve on, including being consistent with the breeding and the fry-rearing," Mr Hale said.