5 things you probably didn’t know about seahorses

How much do you know about these tiny critters?

Although the pot-bellied seahorse is found throughout Australia and New Zealand, not much is known about the species (Photo: Dave Harasti)

You’ve probably seen this adorable creature in the flesh no matter where you’ve gone diving. From male pregnancies to monogamy, there’s so much to learn about the delightful seahorse. Here are five facts for you.

#1 Seahorses are actually fish. But, as you can see, they look totally different to other bony fish under the Atinopterygii class, such as the ocean sunfish (aka mola mola). Some features that set them apart from other fish include their long tubular snout (this snout is used as a little underwater vacuum to suck up their prey, such as small copepods and amphipods) as well as their long prehensile tail, which is very important for seahorses as they use it to curl around a habitat and hold on tightly so they are not swept away in the water column.

#2 The males get pregnant. This is one of the most unique things about the seahorse. The female transfers her eggs into the males’ pouch, which he fertilises, and then the pregnancy stage takes place (this can be from two to four weeks). When ready, the male seahorse goes into labour, and after a series of convulsions, he gives birth to fully developed miniature seahorses. Depending on the species, up to 300 baby seahorses can be born and once out of the pouch, there is no parental care.

#3 They fall in love. Unlike many other marine species that share mates and are promiscuous, some species of seahorses have been found to fall in love and remain faithful to one another. An example of this is the White’s seahorse, which is endemic to Australia. In a seahorse breeding study carried out in Nelson Bay, it was found that several couples bred together for three seasons. The most famous of these couples was Grandpa and Goldilocks; they lived on the same sponge habitat for three years and were regularly seen performing their mating rituals with a small courtship dance in the morning.

#4 Globally, many seahorse species are threatened with extinction. There are approximately 48 recognised species, and of these, 11 are listed as endangered or vulnerable in the wild. The Kynsa seahorse is considered the most threatened as it is only known to occur in three estuaries in South Africa, and these estuaries are heavily urbanised and industrialised. Loss of essential habitats is threatening the survival of several seahorse species in the wild, and if you lose the habitats, you lose the seahorses.

#5 Seahorses need protection. All seahorses are listed on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which means that countries must ensure the use of seahorses is undertaken in a sustainable manner. There are concerns that seahorses have been overharvested for traditional medicine and for the aquarium and curio trade, and several species now face population decline. So avoid buying seahorses in the markets or as souvenirs as these animals have undoubtedly been taken from the wild, threatening their long-term survival.

Dave has spent the past 12 years studying seahorse populations in the wild in NSW, Australia. His PhD was focused on the biology, ecology, and conservation of the White's Seahorse and he works full time as a marine scientist for Fisheries NSW, specialising in threatened marine species and marine protected areas research.