Could a seahorse smaller than your finger still live in the ocean off the coast of Australia?

Despite the questions scientists have about the Bullneck Seahorse, fishing communities and Indigenous communities in coastal Australia still remember the species. Biggs and Gordon spent 10 days visiting eight different communities along the coast from Melbourne to just south of Sydney, asking if anyone had seen the seahorse and if they could share any details about it. They visited bait-and-tackle stores, talked with retired and former commercial fishermen.

“We even went onto the docks as well and talked with people on boats who had just come in from fishing and had good conversations with them as well,” says Gordon. “We only found two individuals who seemed to think that they saw the seahorse back in the ‘80s.”

They estimate they talked with more than 100 people and those interviews helped point them toward a town in Victoria. Looking at photos and illustrations that Biggs and Gordon had comparing the Bullneck Seahorse to juvenile Potbelly Seahorses —a much more common species that lives in shallower waters— two fishermen were adamant that they had seen the seahorse decades ago. They said that seahorse had the defining characteristics of the Bullneck Seahorse— a thick neck and short snout.

“We tracked down the original boat that the holotype came up on in those nets,” says Biggs. “That was really interesting. Again, there’s just lots of generational families there who have continuous knowledge of how landscapes change and how species’ composition changes through their work over decades.” 

Before interviewing communities Biggs and Gordon thought that the seahorse likely hadn’t been seen in almost 30 years because it lived in deep and inaccessible parts of the ocean that are difficult to reach because weather conditions usually don’t allow for it. Their thinking was that it probably wasn’t threatened, but instead has always been rare. 

A similar species, the Ruby Seadragon, another deep-water species, had a similar story. Scientists had originally mistaken it for the Weedy Seadragon, but careful analysis proved it wasn’t. An expedition off of Western Australia using ROVs was able to find the species in the wild. 

“I feel like if the Ruby Sea Dragon —being such a large species— has the same story, and then scientists found it as soon as they started looking for it, [the Bullneck Seahorse]  just hasn’t been found because no one’s been looking for it,” says Gordon. 

The new information Biggs and Gordon got from talking with fishers, divers and even tourism operators made them hopeful and gave them pause. It’s possible that the species hasn’t been seen because it lives in such deep water, but it also might be in trouble.

“Looking for marine species is an entirely different category of difficulty for the Search for Lost Species,” says Biggs. “A lot of terrestrial searches, you can use binoculars, you can use camera traps. There’s a full suite of tools that’s been used for decades in that space that don’t exactly translate over to water environments, particularly this environment off the coast of Eden, Australia. It is rough, open seas. It’s barely been explored.” 

When an expedition team does get in the water, they are not going to be able to just hop in the water and swim around looking for tiny seahorses. They will need specialized equipment, like underwater drones and baited remote underwater video systems (BRUVS). And all of that will have to be perfectly timed with the weather. It’s estimated that out of every 14 days, usually only two days will have calm enough weather to sail up to 16 kilometers offshore from Lakes Entrance. 

eDNA kits and the samples they collect will be the most useful to any expedition team. If they detect any environmental DNA they’ll be able to focus their search efforts much more quickly. But first they’ll need a Bullneck Seahorse DNA sequence to compare any eDNA sequences to. 

“We would really like to get a molecular sequence, a DNA sequence on one of the specimens, which has been notoriously difficult, “ says Biggs. “It’s fixed in formalin, which has been impossible to extract DNA from.” 

The Colossal Foundation, a partner of Re:wild's, is supporting searches for Re:wild’s most wanted lost species, and may be able to deploy their state-of-the-art technology to collect DNA from one of the specimens.