Email this article (Login required)
Email the author (Login required) An ancient shark tale: bridging knowledge gaps on the Galapagos shark (Carcharhinus galapagensis) and other elasmobranch species using traditional and local ecological knowledge in remote Rapa Nui
Submited: 2025-11-11 10:58:05 | Published: 2026-08-31 22:47:19
DOI: https://doi.org/10.3856/vol54-issue4-fulltext-3568
Abstract
Sharks play a crucial ecological role as apex predators, yet many species remain poorly understood, particularly in remote oceanic regions. This study provides the first comprehensive assessment of the historical and contemporary occurrence of the Galapagos shark (Carcharhinus galapagensis) and other elasmobranchs around Rapa Nui (Easter Island), using Local and Traditional Ecological Knowledge (LEK/TEK) from artisanal fishers and divers. Through 25 semi-structured interviews, we documented species occurrence, abundance trends, spatial patterns, and cultural significance. The Galapagos shark was consistently identified as the most common and locally resident shark species. Respondents described clear ontogenetic habitat segregation: juveniles and neonates occur in shallow southern coastal areas, while larger individuals are found offshore. Nearly half of participants perceived population declines since the 1980s, attributing these to historical overfishing, habitat degradation, and reduced prey availability. Twelve additional elasmobranch species were reported, including pelagic taxa such as Isurus oxyrinchus and Alopias spp., as well as deep-sea forms possibly representing undescribed species (Squalus cf. mitsukurii). Sharks hold cultural importance in Rapanui tradition, symbolizing ancestral protection and ecological balance, though much of this heritage is being lost. Our findings highlight southern Rapa Nui as a potential nursery area for C. galapagensis and underscore the need for local management actions, including spatial protection within the Rapa Nui Multiple Use Marine Protected Area. Integrating LEK and TEK with scientific research can significantly enhance conservation outcomes in data-limited, isolated ecosystems.
