111 juvenile endangered seahorses dropped-off at reimagined ‘seahorse hotels’

SEA LIFE Sydney Aquarium’s 3^rd year breeding and releasing White’s Seahorses to save the native species

Following a three year ongoing collaboration to help recover the declining population of the White’s Seahorse, experts from SEA LIFE Sydney Aquarium have successfully bred and raised 111 juveniles, and assisted in their release back into the wild, at 15 reimagined seahorse hotels, in Botany Bay, Sydney.

The species, also known as the Sydney Seahorse, has seen a dramatic population decline over the past decade, and has been listed as ‘Endangered’ in NSW. It is now Australia’s only threatened seahorse species and the second endangered seahorse species worldwide.

This is the third successful seahorse release, from the exciting conservation collaboration, implemented in December 2019, by SEA LIFE Sydney Aquarium in Darling Harbour.

In September 2021, aquarists paired-up breeding adults for third time. Babies were born and raised from October 2021 and put on display in the onsite custom built facilities, enabling visitors to the aquarium, to witness the enchanting creatures first-hand.

In July 2022 the juveniles were carefully tagged for future monitoring, injected just under their skin, with coloured elastomer fish tags in a unique pattern, allowing them to be individually identified.

Daniel Sokolnikoff, Aquarist and Seahorse Expert at SEA LIFE Sydney Aquarium is leading the Sydney Seahorse Breeding Project and commented, “It means the world to the team at SEA LIFE Sydney Aquarium, to lead the charge, collaborating with such highly esteemed experts and to be able to contribute towards the recovery of a species that really needs our help, in our own backyard. We have taken some really exciting steps over the last three years and will continue to do so for years to come”.

The collaboration between industry experts from the Sydney Institute of Marine Science - a collaboration between scientists from the University of New South Wales (UNSW), the University of Technology Sydney (UTS) and industry experts from the NSW Department of Primary Industries (DPI) Fisheries and the Gamay Rangers.

Dr David Harasti, Senior Marine Scientist with DPI Fisheries, has over a decade of experience working with seahorses and will oversee the release and follow-up and said, “Today was another milestone of success in the conservation stocking program. The conservations actions being implemented in this large collaborative project, such as the restocking and the deployment of artificial seahorse hotels, are helping ensure this Endangered seahorse is given every chance to recover.”

This year, joining the former box hotel design of the last 2 years, a new ‘Nautilus shell’ design, with nature-mimicking curves and a fun ‘House’ design were both developed by Dr Kate Dunn and her team of researchers from UNSW’s Built Environment Design Futures Lab, trialling a variety of structures and materials to see if any of them are preferable for the species.

Over the last few months, they have been grown over by sponges, algae and animals that colonise these structures, making them the perfect for seahorses to curl their tails around and call home.

In a “two-for-one” approach, Professor Adriana Vergés and her team of researchers at UNSW and the Sydney Institute of Marine Science have been using the methods developed as part of “Operation Posidonia” to plant Posidonia seagrass, the White’s seahorse preferred natural habitat and also an endangered species, in association with the seahorse hotels.

“We are hoping that by combining the use of seahorse hotels with the restoration of Posidonia we are giving seahorses the best chance of recovery, while we also work on the recovery of their natural habitats,” says Professor Vergés.

To monitor the progress, research students at UTS will conduct regular diving surveys at the seahorse release sites in Botany Bay, to assess the growth, survival and breeding in the wild. They will also determine if there has been migration from one hotel design to another, via the coloured seahorse tag system, to indicate any habitat preferences and inform future hotel designs.