After losing 90 per cent of its population in the past decade, a desperate attempt is underway to breed the Sydney seahorse in an aquarium for release into the wild.

Key points: The Sydney seahorse, also known as the White's seahorse, was classified as endangered in November

The Sydney seahorse, also known as the White's seahorse, was classified as endangered in November Scientists have launched a "world-first" conservation program to save the species

Scientists have launched a "world-first" conservation program to save the species Seahorses are being bred in an aquarium before release into their natural habitat and on 'seahorse hotels'

The seahorse, also known as the White's seahorse, is found on Australia's east coast and was last month classified as endangered, following loss of habitat caused by boat anchors, poor water quality, and sedimentation.

In an effort to recover dwindling seahorse numbers, the NSW Department of Primary Industries (DPI), SEA LIFE Sydney Aquarium and masters students from the University of Technology Sydney have launched a two-part conservation project they are describing as a "world first".

Over the past six months, six pairs of adult seahorses were collected from Sydney's Clifton Gardens and put into tanks at the Darling Harbour aquarium for breeding.

"Once we were able to sort of acclimate them, they've been able to have lots of babies, which we're in the process of rearing and raising," SEA LIFE Sydney Aquarium aquarist Robbie McCracken said.

Project lead Robbie McCracken says the seahorses are "like my children". ( ABC News: Harriet Tatham )

The male seahorses had each given birth to between 50 and 150 tiny babies, measuring less than 1cm in length.

"In the wild, baby seahorses are like underwater Maltesers – everything eats them," DPI senior marine scientist David Harasti said.

"But in the aquarium, they're safe."

No guarantee of survival

While breeding the species in an aquarium drastically increased their chances of survival, Mr Harasti said there was still no proof they would adapt to life outside a fish tank.

"When you raise something in captivity, they behave very differently to how they behave in the wild," he said.

"When we release these animals, there's not somebody giving them food every day or keeping them safe.

"They will be surrounded by fish and octopus that will predate on them, so we're hopeful that they'll adapt to being back in the wild but we're not sure if this is going to work."

The White's seahorse is one of two endangered species of seahorse worldwide. ( Supplied: Sydney Aquarium )

Seahorse hotels

Once the baby seahorses reach 4cm in length, UTS students will tag them for release in two locations, signalling the second stage of the project.

"Everyone of these White's seahorses that we've got here in the aquarium will end up back in the wild," Mr McCracken said.

"It's going to split between the natural habitat, which is a bunch of shark nets [back at Clifton Gardens], and the other option is the seahorse hotels that we put in."

Seahorse hotels are cages covered in chicken wire, created by Mr Harasti to simulate the seahorse habitats that are under threat.

'Seahorse hotels' will be installed on Sydney's sea floor. ( Supplied: David Harasti )

By diving and monitoring the success of both the shark nets and the seahorse hotels, the team will be able to assess whether the new artificial hotels are working and decide whether to build more.

"The installation of the seahorse hotels will also provide a new home for the seahorses within Sydney Harbour, and we will closely monitor how this conservation tool helps the species to recover," Mr Harasti said.

The project is expected to run for two years, or until they have proof it is having a positive impact on the species.