In the seahorse world the pregnancy belongs to the dad, and it is one of the quiet wonders of the harbour. She hands him the eggs, he tucks them into his pouch, and for three weeks he keeps them safe, swaying in the current with the whole next generation on board. Then, one morning, he gives birth, and out of that pouch swim fully formed baby seahorses, sometimes hundreds of them, each one a perfect miniature of him. The species is found only on Australia's east coast, it is named for John White, Surgeon General to the First Fleet, and it is listed as endangered in Australia, largely because the soft habitat it clings to has thinned. So Sydney decided to build it some. The seahorse hotel, an idea from Dr David Harasti of the NSW Department of Primary Industries and Regional Development, borrows its shape from an unexpected teacher: old crab traps, which seahorses had been quietly moving into for years. Each hotel starts as a small frame and is soon covered in sponges, corals and algae, until the structure itself gives way and leaves a living reef behind. SEA LIFE Sydney Aquarium has been breeding White's Seahorses in a purpose built nursery since 2019 and releasing the juveniles onto hotels around the harbour, work now in its seventh year, with hotels at Clifton Gardens, Manly Wharf, Clontarf, Kamay on Botany Bay, and four of them in about six metres of water at Parsley Bay in Vaucluse, just beyond the swimming enclosure.
The loveliest news is what the seahorses have done with the keys. At Cobblers Beach, where fifteen hotels went in during late 2023, surveys found eight seahorses in 2024, then twelve by early 2025, and among them were juveniles most likely born right there in the wild. Divers recorded pregnant males and settled pairs on the hotels through the first half of 2025. Mitchell Brennan, who manages the Sydney Seahorse Project at the Sydney Institute of Marine Science, is pairing the hotels with replanted Posidonia seagrass through Operation Posidonia, led by Professor Adriana Vergés of UNSW, so the hotels are a bridge back to the meadows the seahorses always called home. His hope is a growing wild population and a recovering seagrass meadow, each holding the other up. And the timing could not be sweeter. This Father's Day, in the quiet green water beside the harbour's swimming enclosures, the seahorse fathers of Sydney will be carrying their young through the little hotels a whole city built to bring them home.
Today is Father's Day, and this story is for the dads. For the mini adventures and the chats along the way, the laughs in the kitchen while dinner comes together, the new sport learned side by side, the barracking for the family team. For the book read at night, the driving lessons passing on the skill of the road, and the listening that quietly builds confidence and kindness. For modelling a world of endless possibilities, where there is room to dream, to hope, and to talk it all through on a walk. And for being the shelter when the rain pours down, then the voice that says come back out and look at those bright colours in the rainbow.
However your family is shaped, if you are the one holding that place, this day belongs to you as well. Enjoy the celebration.
Questions you might have
Where can I see a seahorse hotel?
The easiest to reach sit at Parsley Bay in Vaucluse, in about six metres of water just beyond the swimming enclosure, with others at Clifton Gardens, Manly Wharf, Clontarf and Kamay. On a calm day a snorkeller can float over the top and look down. Look only, and let the residents keep their peace.
Do the fathers really give birth?
Yes. The female deposits her eggs into the male's pouch, he carries the brood for about three weeks, and fully formed baby seahorses swim out of his pouch. Among seahorses this is simply how family works.
Why build hotels instead of just protecting the harbour?
The hotels are a bridge, not the destination. Each frame is colonised by sponges and algae within months and eventually collapses into a natural reef, while replanted seagrass grows up around it. The structure does its job and then politely disappears.
One way to take care of these fathers this Father’s Day: the Parsley Bay community is asking for the bay to become a Marine Aquatic Reserve, and you can add your name to the petition.
Photograph: Nicole McMahon, taken at Parsley Bay. Figures from SEA LIFE Sydney Aquarium, the NSW Department of Primary Industries and Regional Development, and the Sydney Seahorse Project at the Sydney Institute of Marine Science, with survey results reported via Phys.org, July 2025.
- Sydney Seahorse ProjectSydney Institute of Marine Science, the hotels and the surveys.
