Basin-scale spatiotemporal distribution of ayu Plecoglossus altivelis and its relationship with water temperature from summer growth to autumn spawning periods

• Published in: Landscape and ecological engineering Vol. 19; no. 1; pp. 21 - 31
• Main Authors: Nagayama, Shigeya, Sueyoshi, Masanao, Fujii, Ryoji, Harada, Morihiro
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 2023; Springer Nature B.V
• Subjects: Autumn; Biomedical and Life Sciences; Civil Engineering; Climate change; Cooling effects; Distribution patterns; Environmental DNA; Environmental Management; Global warming; Landscape Ecology; Landscape/Regional and Urban Planning; Life history; Life Sciences; Nature Conservation; Paraclinus altivelis; Plant Ecology; Plecoglossus altivelis; River basins; Rivers; Spatial distribution; Spawning; Special Feature: Original Paper; Summer; Temporal distribution; Tributaries; Water temperature; Environmental DNA; Sweet fish; Global warming; Spawning migration; Water temperature
• ISSN: 1860-1871; 1860-188X
• DOI: 10.1007/s11355-022-00509-7

As climate warming progresses, it becomes necessary to study the effects of water temperature on the basin-scale dynamic distribution of riverine fish. This study examined the spatiotemporal distribution of Plecoglossus altivelis using the environmental DNA approach and its relationship with water temperature from summer growth to autumn spawning periods in the Nagara River basin, central Japan. The overall results of the spatiotemporal distribution of P. altivelis were consistent with the known life history: a wide-range distribution in the basin during summer and aggregation in the middle mainstem during autumn. Additionally, this study found three intriguing distribution patterns depending on water temperature. During summer (August), the warmest period, P. altivelis was distributed in the upper mainstem, one tributary, and the mainstem downstream of the tributary confluences in relation to the relatively colder water (< 25 °C). During early autumn (September–early October), it spread widely in the middle and upper mainstem without the constraint of the upper limit of water temperature. During late autumn (late October–November), it steadily aggregated to the middle mainstem because of downstream migration for spawning at water temperatures below 20 °C. This study suggests the importance of river connectivity for P. altivelis migration to suitable habitats during its freshwater life stages, upper mainstem and tributaries as summer growth habitats, and cooling effects of tributaries on the mainstem during mid-summer.