2025-12-24 北海道大学,東京大学,海洋研究開発機構
北海道南部の川で捕獲されたニホンウナギ
<関連情報>
- https://www.hokudai.ac.jp/news/2025/12/105.html
- https://www.hokudai.ac.jp/news/pdf/251224_pr.pdf
- https://academic.oup.com/pnasnexus/article/4/12/pgaf384/8384217
Thermal constraints on the distribution of Japanese eel (Anguilla japonica) at its northern limit: Links to land use and geology 北限域におけるニホンウナギの分布を決める水温制約―土地利用・地質との関連性
Kanta Muramatsu ,Mari Kuroki ,Yu-Lin K Chang ,Kentaro Morita ,Osamu Kishida
PNAS Nexus Published:23 December 2025
DOI:https://doi.org/10.1093/pnasnexus/pgaf384
Abstract
Distributions of species can be shaped by large-scale geographic features present at broad spatial scales that control local environmental conditions. In species with complex life cycles, different local factors are expected to determine their distribution at different life stages in a sequential manner. Although the geographic distribution of fish with pelagic life stages (such as planktonic larvae transported by ocean currents) is likely determined by both pelagic stage and post-pelagic stage factors, the role of post-pelagic factors remains poorly understood. In this study, we examined the geographic and local factors that may influence the distribution of the Japanese eel (Anguilla japonica) at its northern range limit. We assessed the abundance of river-dwelling eels in 105 rivers across southern Hokkaido and analyzed statistical models that accounted for the potential recruitment of glass eels estimated through an oceanic transport simulation. Building on these models, we examined how local environmental conditions can influence eel abundance and identified the geographic features that likely regulate those local conditions. We found that Japanese eels were heterogeneously distributed at their northern limit. Our analyses suggest that Japanese eels were more abundant in rivers with watersheds characterized largely by farmland and urban areas and only minimally by volcanic geology, as these rivers tended to have warmer water temperatures during the feeding season. These findings suggest that global warming, in combination with urbanization, may facilitate the northward expansion of the Japanese eel, although in this region, the expansion may be constrained by the past volcanic activity.
