- By contacting underwater photographers and divers and searching for photos and posts on Facebook and Instagram, researchers have confirmed the presence of five species of pygmy seahorses in Taiwan.
- This makes Taiwan one of the world’s pygmy seahorse diversity hotspots, the researchers say.
- Green Island and Orchid Island, in particular, were hotspots for pygmy seahorse diversity, the researchers found, and they hope that these discoveries will help inform conservation planning.
Pygmy seahorses are fascinating animals. These tiny, colorful seahorses measure less than an inch (2.7 centimeters) and match their body colors and textures to those of the vibrant corals they call home. But these diminutive masters of camoflage are also extremely hard to spot. It is perhaps unsurprising, then, that very little is understood about the seven pygmy seahorse species currently known to science.
So, Colin Wen, a marine biologist at Taiwan’s Tunghai University, and his colleagues got creative.
Their hunt for pygmy seahorses initially started with a search for Denise’s pygmy seahorse (Hippocampus denise), a species that was first described in 2003 from Indonesia. The species hadn’t been recorded in Taiwan yet, although Wen and his colleagues had heard of rumored sightings at Orchid Island from their scuba diver friends.
“By chance, shortly after asking friends in the dive industry to record sightings of pygmy seahorses for us, a photo of H. denise taken at Orchid Island surfaced on social media,” Wen told Mongabay.
Encouraged by this, Wen’s wife, Qiaoling, also a marine conservation biologist, suggested that they turn to social media platforms like Facebook and Instagram, both very popular in Taiwan, to look for more records of pygmy seahorses in the country. The researchers began contacting underwater photographers and divers. From 2017 to 2019, they also searched for photos and posts on Facebook and Instagram using the Chinese word for pygmy seahorse as the keyword.
Their searches turned up 259 social media posts, of which 75 included photographs of pygmy seahorses, the researchers report in a new study published in ZooKeys. Many of the photos had their locations listed in the posts. For others, Wen and his colleagues contacted the photographers individually to confirm where the animals had been photographed.
Overall, the researchers managed to identify 78 individuals and confirm the presence of five species of pygmy seahorses in Taiwanese waters: Bargibant’s pygmy seahorse (H. bargibanti), Coleman’s pygmy seahorse (H. colemani), Pontoh’s pygmy seahorse (H. pontohi), Denise’s pygmy seahorse, and the Japanese pygmy seahorse or Japan pig (H. japapigu).
“We were able to verify the majority of species from photos alone ourselves, although we contacted pygmy seahorse experts Drs. Richard Smith and Graham Short, who in addition to advising us on some of the more difficult to distinguish sightings, also led us to a photo taken in Taiwan of H. japapigu,” Wen said.
In fact, the study formally documents the first ever record of the Japan pig outside of Japan, where it was first described as a new-to-science species last year. It also presents the first confirmed records of Denise’s pygmy seahorse from Taiwan. The latter finding was especially exciting, Wen said, since Joseph Heard, the lead author of the study, had been looking for this species since his arrival in Taiwan more than a year ago.
Five of the seven known species of pygmy seahorses have now been confirmed in Taiwan. This makes the country one of the world’s pygmy seahorse diversity hotspots, the researchers say.
“I don’t think anyone would have expected to discover that Taiwan is one of the world’s pygmy seahorse diversity hotspots, matching Japan and Indonesia, both of which are comparatively much larger countries in terms of the number of pygmy seahorse species,” Wen said.
The study is also the first step toward understanding the distribution of pygmy seahorses in Taiwan. Finding out which species occur where is critical to study and conserve a country’s biodiversity, Wen said.
“For example, we found that Green Island and Orchid Island in particular, were hotspots for pygmy seahorse diversity, and we hope that these discoveries can help to inform conservation planning,” he added.
But a lot remains to be studied. Most species are currently listed as data deficient on the IUCN Red List, and much of the seahorses’ ecology, evolution and conservation remains unknown. Collecting some specimens from the wild and studying them in detail could help fill these information gaps, but no specimen of any pygmy seahorse species has so far been collected from Taiwan, the authors write.
Wen says this could partly be because pygmy seahorses usually occur at low densities and very little is known about how quickly they replenish their populations. So taxonomists could be reluctant to collect specimens.
“The rarity of some of these species in Taiwan, particularly H. denise and H. japapigu also makes collecting them very difficult, so we are thankful that ZooKeys and the reviewers of our paper were happy to accept our photos as proof of these new records,” Wen said. “It is, however, important that some specimens can eventually be collected to validate our observations and facilitate further research in Taiwan.”
Heard, J., Chen, J., & Wen, C. K. (2019). Citizen science yields first records of Hippocampus japapigu and Hippocampus denise (Syngnathidae) from Taiwan: A hotspot for pygmy seahorse diversity. ZooKeys, 883, 83-90. doi:10.3897/zookeys.883.39662