Marine biologists off the coast of Kep are giving seahorses fluorescent “tattoos” in hopes of tracking their numbers and curbing illegal fishing.

Of the 48 species of seahorses around the globe, seven have been spotted in Cambodian waters, but little is known about the animal’s local demographics.

“There are lots of questions that we’re still trying to find the answers on with seahorses,” explained Lindsay Aylesworth, 31, a graduate student at the University of British Columbia and lead researcher behind the project.

“Information about where they live, what their population sizes are like, all the different habitats they can live in. Some of those basic questions about where you find them and how long they live . . . we’re still looking to address those basic questions.”

Seahorses are listed on the Convention on International Trade in Endangered Species, the same international treaty that regulates the trade in elephant tusks and rhino horns, with the main threats being environmental degradation and overfishing.

The marine animals are much sought after in Taiwan, Hong Kong and China, where dried specimens are used in traditional Chinese medicine.

Seahorses could be harvested and sold sustainably, said Aylesworth, but catches must be regulated so that fishing does not seriously harm population sizes.

To deduce those population sizes in the Gulf of Thailand, the new project, a joint effort between the Canada-based Project Seahorse and Marine Conservation Cambodia (MCC), a conservation group based on the island of Koh Seh near Vietnam, has divers using tiny needles to inject seahorses with a special dye, known as visible implant fluorescent elastomer or VIFE, visible only under a black light.

“It’s almost like giving the seahorse a tattoo,” said Aylesworth.

Divers would return to the sites and use a black light to find the tagged seahorses.

Coupled with other observations of the tagged animal and its surrounding environment, marine biologists could then work out population sizes, reproductive habits and survival rates.

According to MCC’s British founder, Paul Ferber, VIFE tagging could also help identify the origin of seahorses found in trawlers’ bycatch and determine if fishermen were trawling in protected areas.

There was even the possibility that the ink might show up in dried seahorses sold in CTM markets, data that would give researchers important insights into where fishermen were harvesting seahorses.

The tagging project is being run from the island of Koh Seh, which was granted to MCC by the provincial government for research purposes last year.

Along with their fieldwork projects, the group also conducts regular nighttime patrols in conjunction with the Fisheries Administration for illegal trawling vessels whose activities have destroyed seagrass beds and coral reefs throughout the gulf While VIFE tagging had been used in other parts of the world to track seahorses, this was the first time it has been used in Cambodia, Aylesworth added.

“Doing this sort of tagging study will be able to help us answer some of those questions to better understand the local populations, not only here in Kep and Cambodia but throughout Southeast Asia,” she said.