Miriam Fernandez1, Valentina C. Romagnoli1, Beatriz S. Murillo1, Rodrigo Alarcón-Ireland1, Mauro G. Zucconi1, Mauricio F. Landaeta1,2, Ricardo Beldade1, Sergio A. Navarrete1,3, , Pablo Saenz-Agudelo1,4, Evie Wieters1, Alejandro Perez-Matus1
1Universidad Católica de Chile, Chile - 2Universidad de Valparaíso, Chile - 3Universidad de Concepción, Chile - 4Universidad Austral de Chile, Chile
Mesophotic reef ecosystems are under significant human pressure (e.g., fisheries, climate change). Their remote location and depth present considerable logistical and technological challenges for study, limiting the understanding of their biodiversity, function, and conservation needs, both globally and particularly in temperate zones. Fishers’ knowledge (FK) can offer valuable insights, contributing ecological, biological, and fisheries information on mesophotic reefs. Given the limited information available on mesophotic reefs in Chile, a study was conducted to map the location of mesophotic reefs and contribute to the assessment of biodiversity and exploitation, using FK. Along the coast of northern-central Chile, 29 fisher coves spanning 900 km were visited, and 196 fishers were interviewed. Using FK, it was possible to locate 1,274 fishing spots used by artisanal fishers on mesophotic reefs over the course of one year. The average depth and size were 49.4 m (± 26.5) and 1,619 km², respectively. The number of fishing spots exploited by fishers ranged from 14 to 27 among the fishing coves, while the area of use for fishing spots on mesophotic reefs varied substantially (between 21 km² and 1,842 km²). After fishers identified the location of fishing spots in mesophotic areas, 100 spots were randomly selected and visited, validating 98% of the sites reported. Fishers identified over 40 mesophotic reef species, dominated by Sebastes oculatus and Genypterus chilensis, two exploited species. Most fishers (76%) perceived a reduction in the abundance of the main target species exploited on mesophotic reefs. Chile has designated more than 40% of its Exclusive Economic Zone as marine protected areas. However, along the study area (a) only 92 of the fishing spots were within Marine Protected Areas of Multiple Use (7.2%), and (b) only one fishing spot overlapped with a no-take zone, suggesting the urgent need to focus conservation efforts on mesophotic ecosystems.