Wesco (Japan)

Summary Seabirds are experiencing a decline in their populations because of climate change and human activities. Understanding their spatiotemporal dynamics is crucial for effective conservation, but the distribution and movement patterns of pelagic seabirds are not yet fully elucidated. In the present study, we investigated the seasonal movements and wintering areas of Swinhoe’s Storm-petrel Hydrobates monorhis , a Near Threatened species that breeds primarily on islands in the north-western Pacific. The data analyses of geolocators retrieved from four birds showed that Swinhoe’s Storm-petrels migrated across the north-western Pacific and Indian Oceans and wintered in the Arabian Sea. The distance between their breeding colony and the wintering area was approximately 6,700 km, and the tracking distance for a seasonal migration exceeded 12,000 km. The migration pathway was characterised by large-scale movements in both north–south and east–west directions in the Eurasian offshore regions, which previously had been inferred from direct observations at such areas but not empirically confirmed. Wintering areas in the Arabian Sea overlapped with regions where plankton blooms are triggered by the monsoon in winter, which may produce high marine productivity and support the wintering of Swinhoe’s Storm-petrels in this sea area.

農業水路における環境配慮区間内での魚類の移動および有効性について検討することを目的とし，複数の環境配慮工法が施工され，非灌漑期においても水涸れしない岡山県総社市の農業水路に 5 ヵ所の調査地点を設定し，調査を実施した．この調査では，2014 年 7 月から 2015 年 12 月にかけて計 6 回，主要生息魚種のフナ属・アブラボテ・カネヒラ・ヌマムツ・ドジョウ・ドンコの 6 種を対象とした標識魚の追跡を実施した．その結果，計 133 個体の標識個体が再捕獲され，そのうち 114 個体は環境配慮区間の同一地点内で捕獲された．すなわち，長期間に及び環境配慮区間の同一地点に留まる個体が多数認められた．このことから，調査水路に施工された環境配慮工法は，魚類に対して好適かつ恒常的な生息場を提供していると考えられた．したがって，非灌漑期でも通水があり水深が低下しない水路では，有効な保全工法を伴う区間が確保されていれば，魚類の恒常的な生息場として有効に機能すると思われた．