Coastal development threatens Datan area supporting greatest fish diversity at Taoyuan Algal Reef, northwestern Taiwan

Taoyuan Algal Reef is a biodiverse coralline algal reef in north‐west Taiwan, that is currently threatened by coastal development and industrial waste runoff. As the reef lies in an exposed area that is frequently disturbed by monsoons, it is difficult to survey using traditional methods. Knowledge of the reef is therefore limited, and has until recently, long been regarded as a barren environment. However, recent studies have revealed that the reef is inhabited by a diverse array of organisms, particularly at Datan, where a natural gas receiving terminal is planned for construction. Due to challenging environmental conditions, otolith assemblage and soundscape analyses were used to supplement traditional sampling methods including clove oil, netting, and pole‐and‐line fishing in order to assess the diversity of the fish community at Taoyuan Algal Reef. Several fish species that had not been recorded by previous surveys were observed. Fish diversity and the average size of commercially targeted species were greatest at Datan G2. Predatory reef fishes such as groupers (Serranidae) and snappers (Lutjanidae), as well as several small endangered scalloped hammerhead sharks Sphyrna lewini were recorded at G2, where otolith assemblage analysis also indicated increased predatory activity. However, fewer individuals and species were recorded from tidal pools across all sites compared to previous surveys, suggesting a loss of biodiversity. If construction work resumes at Datan, it will be likely to have adverse consequences for the reef itself, the species that inhabit it, and by extension, the local fishermen that rely upon it. Halting additional coastal development, reducing industrial and domestic pollution, as well as improving the management of traditional fisheries is recommended to protect this unique reef ecosystem from further degradation.