Sydney Harbour is one of those estuaries along the NSW coast blessed with the occurrence of seahorses. One in particular is Hippocampus whitei Bleeker 1855. It was named after John White, the Surgeon General of the First Fleet. Much detail can be found online about this species including an information sheet from NSW DPI Fisheries, and a paper in 2019 by Mark McGrouther on the Australian Museum web site. In is not my intention to reproduce any of this material.

Over the years, Irene and I love to snorkel in harbourside and open ocean waters of the eastern suburbs. We have witnessed some amazing things, and fully appreciate the healthy conditions of these waters today compared to our youth. But we have one great frustration and that is sighting seahorses!

As shown in risk assessments by Marine Estate Management Authority and others, there are on-going threats to habitats and animals in our estuaries. Seahorses are especially at risk from pollution impacts and destruction of seagrasses and soft corals in which they live. Boat moorings can be especially damaging. White’s seahorse is listed as a threatened species and steps are being taken to maintain and improve its continued viability in these waters. These steps include an active breeding program and monitoring in areas frequented by swimmers and boats.

Woollahra Council is undertaking a series of surveys at netted swimming areas over the next 12 months to establish a baseline data set for the purpose of determining actions necessary to support the populations found within this LGA. I wish to congratulate Council on this initiative and to thank them for providing information contained in this blog.

Council engaged John Turnbull to do these surveys (John Turnbull, #marineexplorer). Information will be gathered on seahorse species and numbers including male/female and adult/juvenile. The presence of other animal species of interest will be gathered such as nudibranchs, cuttlefish, and other fish species. Documentation will also be visual by both photos and videos. The focus will on netted swimming areas in Sydney Harbour managed by Council with a clear aim to help in the protection of the ecology of this iconic waterway. John’s images from the most recent survey can be found at LINK ( They are enlightening.

In the meantime. Irene and I will continue our search. We surmise that as this species is so well camouflaged, and likes depths below 1m, our snorkelling skills ability will need to be improved.  But we can only keep trying. Woollahra Council in supporting this monitoring is providing residents and visitors with a tremendous opportunity to encounter this wonderful animal.

Bruce Thom

Words by Prof Bruce Thom. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2021. For correspondence about this blog post please email