Underwater hotels for homeless seahorses

Wild storms have wrecked seahorse habitats across the Australian east coast. Vast volumes of sand smothered the soft coral, sponge and seagrass homes of the White’s seahorse. As a result, about 90 per cent of the population was destroyed. 

Now the race is on to rehouse the survivors.  

A closeup of a seahorse
Adult White’s seahorse. Credit: Sydney Aquarium

Researchers from the University of Technology Sydney are working with New South Wales DPI Fisheries and Sydney SEA LIFE Aquarium to build seahorse ‘hotels’.

It’s a housing program aimed at restoring their habitat and helping the population grow again.

“Just last year, the White’s seahorse was listed as an Endangered species in NSW,” said Dr David Harasti, Senior Marine Scientist with DPI Fisheries.

Seahorses can’t swim. Instead, they wrap their tails around seagrass and corals to avoid being carried away by currents. Camouflage hides from predators such as crabs.

See more seahorses

The UTS researchers discovered refugee seahorses taking up residence in abandoned fishing nets and old crab traps scattered about the bottom of the ocean after their natural coral homes were destroyed between 2010 and 2013.

This inspired them to build cages of net and steel that algae, sponges and corals can colonise over time, creating a safe, welcoming environment for the endangered seahorse. The metal hotel frame will eventually erode, leaving behind an entirely natural habitat.

In 2019, the researchers caught eight pairs of breeding White’s seahorses from Sydney Harbour, including pregnant males.

The seahorses were placed into a custom-built breeding facility at SEA LIFE Sydney Aquarium.  Dozens of White’s seahorse fry have already been successfully bred on site.

Last year, the team released 90 seahorse fry into Sydney Harbour, placing them in purpose-built hotels. This week, 140 more ‘checked in.’ 

Before setting them free, researchers tagged them all with a unique fluorescent ID inserted beneath the skin to track how they get on.

Sea horses in a clear bag
Seahorse release. Credit: Sydney Aquarium.

“We’re now in year two of a multi-year project that aims to recover the Endangered White’s seahorse,” Laura Simmons, curator at SEA LIFE Sydney Aquarium, says in a press release. “I’m extremely proud that today we saw over 140 tagged White’s seahorses released into the wild, where we hope they’ll go on to breed all around Sydney Harbour and the East Coast of Australia to help White’s seahorse flourish.”

“The captive breeding program and Seahorse Hotels initiative is providing hope for this iconic and mythical marine species,” adds  Dr Harasti. “We hope it will contribute to their numbers increasing in the wild.”

Hotel for sea horses

Seahorses are facing the loss of habitat in many parts of the world. Illegal trade for traditional medicine use, aquariums, and their sale as dried curios continue to decimate their populations.

Similar rehabilitation projects have sprung up across the world. In South Africa, for example, the endangered Knysna seahorse colonised wire cages filled with rocks used to build a new marina.

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