Scientists confirm horseshoe crabs in a second Philippine province, urge conservation.
Philippine researchers reported horseshoe crabs in Tawi-Tawi province for the first time, using interviews with 142 residents, and said science-based conservation should follow. Before this, the animals had been recorded only in Palawan.
Philippine researchers have reported the presence of horseshoe crabs in Tawi-Tawi, a southern island province, for the first time. The finding comes from interviews with local residents. According to Mongabay, scientists had previously recorded the animals in the country only in Palawan province.
In the study, fishers and coastal residents described two distinct species with features resembling the tri-spine horseshoe crab (Tachypleus tridentatus) and the mangrove horseshoe crab (Carcinoscorpius rotundicauda). The tri-spine is listed as endangered on the IUCN Red List. The mangrove horseshoe crab is listed as data deficient, meaning little is known about its conservation status. The identification rests on residents' descriptions, and the report says the team has potentially documented the two species.
Ivane Pedrosa-Gerasmio, the study's corresponding author and an associate professor of marine sciences at Mindanao State University, Iligan Institute of Technology, said locals told her about seeing horseshoe crabs when she visited a market in Bongao, the provincial capital, in December 2023. She shared the news with her student Quesie Tolero Omnos, and the two decided to investigate.
The team interviewed 142 residents across four municipalities. They asked where people had seen horseshoe crabs, how often, how the populations had changed, and how the animals were collected and eaten. Locals call them "bangkas" because of their boat-like shape. Those interviewed reported seeing them on sandy beaches, in mangroves, among rocky coral and seagrass, and in water 10 to 15 meters (32.8 to 49.2 feet) deep in Bongao and other coastal towns such as Simunul, Sitangkai and Panglima Sugala.
Residents said horseshoe crabs are captured for medicine to treat asthma and other illnesses, and for rituals for people believed to be possessed by bad spirits. More than half of those interviewed thought numbers were declining. They pointed to possible causes including collection for medicinal use, climate change and industrial pollution.
Mongabay notes that only four horseshoe crab species are known, three of them in Asia, and that all Asian populations are declining. Omnos said conserving the two species is important because of their ecological significance, possible pharmaceutical applications and cultural value to local communities. She said conservation should begin with enough scientific evidence on occurrence, distribution, population status and threats, so local government units can build science-based management plans.
Note: The headline says scientists confirmed horseshoe crabs. The page says presence was confirmed through resident interviews, and the two species are described as resembling known species and potentially documented, not formally identified.
At a Glance
- Researchers interviewed 142 residents across four municipalities in Tawi-Tawi, Philippines.
- Horseshoe crabs had previously been recorded in the Philippines only in Palawan province.
- The tri-spine horseshoe crab is listed as endangered on the IUCN Red List.
- The mangrove horseshoe crab is listed as data deficient by the IUCN.
- More than half of those interviewed thought horseshoe crab numbers were declining.
Sources
This brief was written by Brightside Report from the reporting linked above. Spot an error? Request a correction.