TAIPEI (Taiwan News) — The Highway Bureau said on Monday (Aug. 19) it will improve a land crab road crossing near Banana Bay to facilitate the animals’ migration.

Highway Bureau Southern Region Branch Office Director Chen Guei-fang (陳貴芳) said man-made structures like water pipes have caused crabs to fall into ditches and struggle to escape. After consultation with experts, Chen said coral stone and driftwood will be added to the crossings, creating a more crab-friendly environment, per CNA.

Banana Bay boasts Taiwan’s most diverse land crab population, once home to 62 species, or 95% of the country’s total. However, Provincial Highway 26 cuts through the area, dividing the coastal forest.

Every year between May and October, land crabs cross the highway to release their young into the ocean, resulting in numerous roadkill incidents. While volunteers escort crabs across the highway yearly, the effort requires a large number of people and is limited to specific hours, per an Our Island article.

Land crab researcher Liu Hung-chang (劉烘昌) recommended building crossings instead of relying on human escorts. The Highway Bureau modified culverts with climbing aids to create the first crossings in 2017.

Six years later, the bureau raised a 500-meter section of Provincial Highway 26 and installed culverts below to provide safe passage for crabs. Tunghai University researcher Tsai Chuan-ju (蔡鵑如) compared roadkill statistics and found a decline in incidents, concluding that purpose-built culvert crossings are the most effective method.

Traffic control on Provincial Highway 26 in the Banana Bay area will be in place from 6:30 p.m. to 8:30 p.m. for July 18-20 and Aug. 18-20. For Sept. 17-19, the control period will be from 6 p.m. to 8 p.m.

During these times, two of the highway’s four lanes will be closed in 10-minute intervals. Volunteers will be stationed at land crab crossing hotspots to monitor the situation and assist pregnant crabs in reaching the seashore.