Tasmanian red handfish bred in captivity released

The handfish were raised from eggs at the Institute of Marine and Antarctic Sciences, the CSIRO and Seahorse World.

"Habitat degradation is a key issue for the remaining populations - with impacts from multiple sources, one of which is overgrazing of seaweed (which red handfish live under) by urchins," IMAS and CSIRO lead researcher Jemina Stuart-Smith said.

Raising the red handfish juveniles in captivity before releasing them into the wild is a process known as head-starting.

Dr Stuart-Smith said it was designed to improve a species' chances of surviving to maturity by protecting them while they were young and vulnerable.

"While the juvenile handfish grew in the safety of aquariums, IMAS worked with the Tasmanian Commercial Divers Association to improve their habitat for release by harvesting urchins at handfish sites, which allowed the seaweed to start to grow back," Dr Stuart-Smith said.

"This is a temporary solution and just one of the strategies we need to implement to restore ecosystem balance and protect the species, but it meant we could return the juveniles to improved habitat."

Dr Andrew Trotter, who led the aquaculture team providing care for the IMAS juvenile handfish, said there had been a few challenges along the way.

"We have had a team of highly experienced aquaculture staff watching their every move, and while culturing the species is relatively straight forward, they do appear to be susceptible to gill parasites and need live feed throughout their time in captivity," Dr Trotter said.

"Their rarity added some pressure to the job, and throwing in a global pandemic in the midst didn't help either, so to have 42 healthy juvenile handfish over five centimetres in size released is a credit to the staff involved," he said.

Dr Stuart-Smith said the pre-release strategy also included 'handfish school' to prepare them for life in the wild, with conditioning conducted at CSIRO and IMAS.

"We set up aquariums to mimic wild conditions with seaweed and other species they are likely to encounter, and trialled different prey types.

To help raise funds to support the research, Handfish Conservation Project website has profiles of the 100 known adult red handfish which can be named/sponsored.