Two citizen scientists scuba diving off the coast of Nova Scotia recently spotted a species of seahorse rarely documented in Canadian waters.

Nédia Coutinho and Martin Roy made the discovery during a dive in St. Margarets Bay, located about 40 kilometres from Halifax.

“I was obviously not looking for a seahorse, but when I saw it, I could not believe my eyes,” said Coutinho on the University of British Columbia's website.

“I was so excited, even without knowing that it’s not common around Nova Scotia. I have dived on the Great Barrier Reef in Australia and in the Caribbean and this is the first time I have ever seen a seahorse.”

The pair reported the discovery to Project Seahorse, UBC's online seahorse tracking website.

UBC researchers Amanda Vincent and Heather Koldewey started the program in 1996 to study and help protect vulnerable seahorse species across the globe.

“This is a thrilling discovery,” said Vincent in a release.

“These charismatic and mysterious animals are so highly cryptic — and, in many places, so threatened — that we often have to be very lucky to find them.”

Lined seahorses typically live in coastal waters along North and South America, the Caribbean and the Gulf of Mexico. They're listed as vulnerable to extinction under the International Union for Conservation of Nature.

The seahorses, which grow in length to be about 19 centimetres, can develop elaborate skin fronds in order to camouflage themselves within seaweed.

According to the Project Seahorse website, many species are threatened by harmful overfishing. Part of the problem is that millions of the animals are caught and used in traditional Chinese medicine, caught for aquariums or dried for decorative purposes. Loss of habitat also poses a problem for seahorse populations.

“Seahorses face so many challenges that they desperately need new allies,” said Vincent. “Globally, there are fewer than 15 scientists studying seahorses in the wild, which is why citizen science initiatives like iSeahorse are so important, and why divers like Nédia and Martin are so integral to their conservation.”

There are dozens of seahorse species scattered in coastal waters across the globe. The specific number of species is difficult to pinpoint since seahorses have the ability to change their skin colour and grow skin filaments to blend in with their surroundings.

Divers and snorkellers who spot seahorses are encouraged to upload information to the iSeahorse website, or use the handy iPhone app.