A Tagged White's Seahorse Juvenile. Source: D. Harasti.
The endangered White’s seahorse (Hippocampus whitei) is a ~12 cm fish endemic to the coast of New South Wales, meaning that its geographic range is restricted to only between Sydney and Southern Queensland, with a few exceptions. Its color can vary given its camouflaging abilities, but its “natural” color seems to be yellow, gray, or brown. White’s seahorse, like other seahorses, is unique in that it places the responsibility of offspring care onto the male parent, who fertilizes the eggs inside his pouch. It is believed that male seahorses bear this responsibility to enable females to “prepare” more eggs, thereby increasing the population of the next generation and, theoretically, ensuring the species’ survival.
White’s seahorse is named after John White, joining other species like White’s tree frog whose namesakes are the rather obscure author of A Journal of a Voyage to New South Wales. To his accounts, White appended various engravings of Australian wildlife, including one of a seahorse. Whether the seahorse engraving is the first depiction of White’s seahorse, or even White’s seahorse in the first place, is unclear.
While the etymology of its name may be uncertain, White’s seahorses are undoubtedly under threat due to habitat loss. At Port Stephens, boat moorings, boat anchors, and geographical changes have destroyed over 90% of White’s seahorse habitat. March floods in 2021 also contributed to the decline of essential coral off the coast of NSW that had helped keep the seahorses protected from predators like fish. Seahorses require visually complex environments for their color-changing camouflage to work effectively, and if floods like those that occurred in March become more common, the lack of safe hiding places will likely drive these seahorses to extinction.
White’s seahorses are particularly vulnerable to habitat loss because they show “strong site fidelity”—in a study of the seahorses’ behavior, researchers recorded a specimen remaining on the same holdfast for a year and 5 months. Interestingly though, White’s seahorses have been able to adapt to the intrusion of man-made foreign objects in the sea, using nets and cages as replacements for increasingly scarce natural shelter. Conservationists have placed and maintained artificial habitats, including swimming nets, to mitigate the effects that population pressure and habitat loss have had on the seahorse population. In addition, DPI Fisheries, NSW’s government organization that oversees fishing practices, has been working to improve the protocols pertaining to the cleaning and repair of such artificial habitats in an attempt to prevent the injury of seahorses during the process. The SEA LIFE Sydney Aquarium has also successfully bred White’s seahorses in captivity and reintroduced them into the wild in a hopeful step towards the species’ survival.
A Close-Up Image of a White's Seahorse. Source: Australian Museum.