

We’re saving endangered seahorses in Sydney Harbour
Sydney Harbour isn’t just famous for its iconic Opera House and massive Harbour Bridge, it’s also home to a hidden underwater world teeming with marine life. Among its most extraordinary residents is the rare White’s seahorse, a tiny, delicate fish that clings to seagrass for survival. But as their seagrass habitat rapidly disappears, so do their numbers—declining by up to 90% in some areas of the harbor. Thankfully, an Australian scientist and his team at the Sydney Institute of Marine Science (SIMS) are giving these tiny sea creatures a second chance.
The mission
Their multi-pronged approach combines breeding, habitat creation, and seagrass restoration to help the species recover. The team carefully collects pregnant male seahorses—yes, in this species, the fathers carry the young—allowing them to give birth in a controlled environment. After the birth, the dads are returned into the wild— to the exact same spot they were collected from. The babies remain in the lab for a few months, increasing their survival rate from just 1% to 20%. Additionally, to make sure the seahorses have a safe haven in the wild, SIMS is building “seahorse hotels”—metal structures that transform into semi-natural reefs. Alongside this, they’re actively rebuilding seagrass meadows.



Through their breeding efforts, the creation of underwater habitats, and the regeneration of seagrass meadows, SIMS is helping the seahorse population bounce back. Thanks to the Planet Wild community, we were able to support them in their multi-faceted approach. We funded the release of up to 500 seahorses, built three new seahorse hotels, and restored 500 square meters of seagrass—giving these incredible creatures a real shot at survival.
What we achieved
Ideal outcome
Our Partner
Mitchell is a marine biologist who focuses on protecting endangered ocean animals, especially seahorses, seadragons, and pipefish. His research is dedicated to helping the endangered White’s seahorse by breeding them in aquariums, studying their survival in the wild, and creating safe habitats for them. Through his project, the Sydney Seahorse Project, he works with other scientists and students to develop the best ways to care for and conserve these unique marine creatures.
Our Partner

Mitchell is a marine biologist who focuses on protecting endangered ocean animals, especially seahorses, seadragons, and pipefish. His research is dedicated to helping the endangered White’s seahorse by breeding them in aquariums, studying their survival in the wild, and creating safe habitats for them. Through his project, the Sydney Seahorse Project, he works with other scientists and students to develop the best ways to care for and conserve these unique marine creatures.