18/08/2015 12:26 AM AEST | Updated 31/08/2016 9:33 PM AEST

Threatened Seahorses At Risk Of Illegal Poaching From Sydney Harbour, Climate Change

Video by: Tom Compagnoni

Australia's seahorse population is being decimated amid fears that illegal poachers are stealing them from Sydney Harbour and trading them on the black market.

The protected animals are dried and ground for use in Chinese medicine in a bid to treat everything from erectile dysfunction to skin rashes, while buyers are also picking them up on the cheap to put in aquariums in Australia and Asia.

Boat traffic and increasingly warm currents are also factors contributing to the dire drop in population, prompting marine experts to declare the species "on the brink of survival".

But world-first photo ID technology and eco-friendly 'seahorse hotels' are the frontline defences of scientists and citizens desperate to save the rare and stunning creatures.

Dave Thomas, the founder of marine conservation group Ecodivers, said illegal poaching was a major threat to their existence.

"Seahorses are a protected species because they're such a fragile marine animal," Thomas said.

"They're very prone to being taken for aquarium trade and Chinese medicine.

"They are on the brink of either survival or not survive as a population -- especially in Sydney Harbour."

Professor William Gladstone from the University of Technology Sydney School of Life Sciences agreed poaching was a concern.

"When you talk to the students who are down there counting animals on the nets all the time, they tell you poaching is a problem," Gladstone said.

"They're used for traditional Chinese medicine but from a medical point of view, it's a myth that needs to be busted."

Weedy sea dragons bred at Seahorse World for Seahorse Australia. Picture: Gary Bell

Seahorse Australia is the only organisation in the nation legally allowed to breed seahorses for sale. Managing director Craig Hawkins said he received calls every week from people wanting to buy seahorses for medicinal purposes.

Hawkins said the team originally tried to placate the medicine market by selling farmed seahorses.

"If you could grow ivory, you'd do it to save the elephants," Hawkins said.

"Ultimately seahorses are a fish and a lot of fish are farmed -- they're just a particularly pretty fish and we thought that if we could supply farmed seahorses, they wouldn't be poached from the wild."

But Hawkins said the price of a farmed seahorse was too high for the dried medicine market.

"We get lots of enquiries for dried seahorses but we've never had someone pay what we need to make it viable to farm them in captivity," Hawkins said.

"Seahorses are bought by weight and sold on the street for about $30. It takes about 12 months to grow a seahorse to the size they want and when you take into account the cost of the tanks, air conditioning ... one seahorse costs more than they're willing to pay."

A 2013 study in the Journal of Food and Drug Analysis of 58 dried seahorses for sale in a Taiwan market found four Australian species were present.

A major research project into weedy sea dragons currently underway in Sydney may have come up with a novel way of deterring poachers.

The Dragons of Sydney project is recording weedy sea dragons at sites from Pittwater to Port Hacking and each animal is being photographed.

Its unique markings are then recorded by software originally designed for tracking manta rays and Underwater Research Group's John Turnbull said this database could stop illegal trading.

"It's the first time anyone in the world has used this software on weedys and it works really well," Turnbull said.

"If we get the word out that these animals have been identified, if people know we've got their photo ID, and the animal turns up in a zoo for example, we can say 'that's a wild animal and it came from Sydney'.

"Potentially that will act as a deterrent."

However Fisheries NSW Marine Scientist Dr David Harasti said the biggest problem facing Sydney's seahorses is climate change, not poaching.

"I've worked for fisheries since 2006 and in that time, there's only ever been one reported incident of someone catching a seahorse in the wild," Harasti said.

"I would say there's no black market trade for seahorses in Sydney."

Harasti said the white's seahorse is currently being considered for the NSW threatened species list and habitat loss is a big factor.

"White's seahorses on the Manly nets are about half of what they used to be," Harasti said.

"In Port Stephens, one population is down 95 percent, absolutely decimated – while the other population is down 75 per cent."

Sea dragons and seahorses rely on algae and kelp to hide from predators. Picture: Gary Bell

He said the answer to protecting Sydney's seahorses may simply be caring for the kelp, soft coral and sponges they live in - which can be destroyed by boat anchors on the Harbour.

"Their habitat of sponge gardens and soft corals is pretty much wiped out in Sydney. Now they live on swimming nets and sometimes sea grasses. Every time a boat drops an anchor into a seagrass bed, it destroys that part of habitat," Harasti said.

"We need to get people to stop anchoring in these environments."

Kelp favoured by weedy sea dragons is also disappearing and Turnbull said the Eastern Australian Current -- made famous by Finding Nemo -- was partly to blame.

"South-East Australia is warming faster than anywhere in the world and the Australian Eastern Current is getting warmer and stronger," Turnbull said.

"Tropical water has less nutrients in it and kelp relies on those nutrients suspended in the water. The kelp is struggling and I suspect this could be the reason why weedys are disappearing."

Reporter Cayla Dengate checks out a seahorse at Parsley Bay. Picture: Dave Thomas

Another stronghold for white's seahorses is in Parsley Bay, and Woollahra Council is consulting with Ecodivers to create a 'Seahorse Hotel' - a year-round net in the water.

Thomas said it's working.

"It's a stronghold for the species," he said. "You see about 30 to 50 seahorses down there, and that number will hopefully grow the longer the net stays there."

This story was originally published on August 18, 2015.