New Taipei Bitan Weir adds new rope ladders to aid crab migration
新北碧潭水壩新增麻繩階梯，協助螃蟹遷徙
| TAIPEI (Taiwan News) — The New Taipei Water Resources Department has installed new rope ladders on the Bitan Weir to support the upstream migration of horsehair crabs.
Department Director Song De-ren (宋德仁) said Thursday that the ropes are meant to assist the crabs, which hatch near river mouths and migrate upstream to mature in freshwater environments, per CNA. The ropes are replacements for older ones that had become worn. To better understand crab migratory behavior, the department has also deployed trapping cages to track their routes and habitats. New Taipei Mayor Hou Yu-ih (侯友宜) visited the site Thursday and said the return of horsehair crabs signals success in restoring the Xindian River’s ecosystem. He emphasized the fish ladder’s role in reconnecting the upstream and downstream ecological zones separated by the weir. However, the fish ladder have drawn criticism after videos surfaced showing a large number of bighead carp, an invasive species, using them to migrate upstream, per CNA. In a joint statement, the R.O.C. Society of Streams and other environmental organizations warned, on April 17, that the fish ladder may be enabling the spread of invasive species, calling it a risk rather than a success. The statement also argued that the only real way to restore the river’s ecosystem is to remove man-made obstructions. National Taiwan Ocean University Professor Chen I-Shiung (陳義雄) echoed those concerns, warning that invasive species could cause further ecological damage if allowed to move upstream, per UDN. He urged authorities to first manage invasive populations before fully linking upstream and downstream habitats. In response, the Water Resources Department said the fish ladder was designed to be accessible to most native aquatic species. This inclusivity, they noted, makes it difficult to block invasive species without also hindering native ones. Former Tsing Hua University Professor Tzeng Chyng-shyan (曾晴賢) added that pre-construction surveys had identified the native species present, per UDN. While he acknowledged it’s possible to manually remove invasive species from the weir, he said such efforts would be unsustainable due to cost and manpower constraints. |
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| Medwin Hsu Taiwan News, Staff Writer | |
| 2025-07-03 |
