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In a landmark event ten months in the making, a group of aquarium bred White’s Seahorses have been released into Sydney Harbour as part of a critical conservation project aimed at helping recover this iconic Endangered species.

The White’s Seahorses – affectionately known as the Sydney Seahorse – were part of a recovery project led by SEA LIFE Sydney Aquarium in collaboration with the NSW Department of Primary Industries (DPI) Fisheries and the University of Technology Sydney (UTS).

The purpose of the project was to successfully breed, raise, and release the White’s Seahorses into the wild and monitor their success in helping reverse the decline of this iconic endangered species.

 Four key stages of this project are now complete 

  1. Collect:

After planning since August 2019, the project kicked off in October 2019 when the SEA LIFE Sydney Aquarium team worked closely with experts from DPI Fisheries and UTS to collect breeding pairs from Sydney Harbour, including some pregnant males.

  1. Breed:

The seahorses were then placed into a custom-built seahorse breeding facility at SEA LIFE Sydney Aquarium, where dozens of White’s Seahorses were successfully bred on site and on display for curious guests at the aquarium.

  1. Prepare hotels:

In March this year, nine Seahorse Hotels were then placed underwater in Clifton Gardens, Mosman in preparation to become homes for the juvenile seahorses being raised at the aquarium.

  1. Tag and release:

The final stage involved the juveniles being carefully tagged for future monitoring. The seahorses were injected just under their skin with a coloured elastomer fish tag in a unique pattern, allowing them to be individually identified. Today the tagged seahorses were successfully released into their Sydney Harbour ‘Seahorse Hotels’ whereby it is hoped that the colony will help reverse the decline of this iconic Endangered species.

The decline in the White’s Seahorse is largely due to habitat loss and degradation – with much of their natural seagrass, sponge and soft coral habitats disappearing – meaning that providing new artificial habitats was a key element in the recovery program. The breeding, release, and follow-up monitoring of these seahorses and the hotels they will live on will help shape and expand the long term conservation and recovery of this species.

Robbie McCracken, Aquarist and Seahorse Expert at SEA LIFE Sydney Aquarium has led the project over the past ten months and commented: “I’m thrilled that this project has been such a success thus far and it’s been amazing to see visitors to the aquarium witness first-hand how incredible these creatures are. Since our collection in October ‘19, we have successfully bred dozens of White’s Seahorses and to see these healthy, strong juveniles be released into the wild is an amazing milestone in such a critical project for the species.

“While all of the other stages have been important, today was definitely a highlight in the recovery program as we watched our seahorses settle into their new homes. With the help of DPI Fisheries, UTS, Ocean Youth, The Gamay Rangers and Transport for NSW, we’ve worked hard to create new environments for the seahorses and we look forward to seeing them flourish in the wild.”

Dr. David Harasti, Senior Marine Scientist with DPI Fisheries, has over a decade of experience working with seahorses and oversaw the release: “Today was a momentous occasion, having released our seahorses into Sydney Harbour in an effort to save the population. Now we’ll be conducting regular diving surveys to monitor their growth, survival and breeding in the wild. This monitoring program is critical for assessing how the Seahorse Hotels, as a conservation tool, helps the species to recover”.

To help support the husbandry of the seahorses and the long-term research, Dr. David Booth, Professor of Marine Ecology at UTS is supervising a Masters Research student and said: “UTS [Fish Ecology lab] will continue to collaborate with the upcoming release of juvenile seahorses, with UTS Masters research student Brooke (Bee) Kyle tracking the success of the new releases and how they fare in their new hotels over the ensuing months/years”.

Seahorse Hotels

Inspired by discarded crab traps, Seahorse Hotels were trialled in Port Stephens in 2018 and 2019 and were found to be very successful in attracting seahorses which led to mating and breeding.

The Seahorse Hotels start as artificial habitats that grow into natural habitats once they are placed in the marine environment. Over time they are grown over by corals, sponges, algae and encrusting animals that colonise these structures, providing protection from predators and a ready supply of food, making them the perfect home for seahorses. Seahorse Hotels are designed to be completely biodegradable, so the artificial structures will slowly collapse over time under the weight of the marine growth leaving a new natural habitat behind.

The SEA LIFE Trust’s ‘Ocean Youth’ helped with the Seahorse Hotel construction, along with Seadragon Diving Co. and Sydney-based Indigenous Sea Rangers with support from DPI’s Marine Estate Management Strategy (MEMS). 

White’s Seahorse also known as the Sydney Seahorse

The species was named after John White, Surgeon General to the First Fleet and is endemic to the east coast of Australia. White’s Seahorses can be found in a variety of colours and they can change their colour to match what they are living on.

Following a dramatic decline in numbers over the past decade, White’s Seahorse (Sydney Seahorse) has recently been listed as an ‘Endangered’ species. It is now Australia’s only threatened seahorse species and the second Endangered seahorse species worldwide.