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学術研究成果リスト

Detail of Grant Awarded Academic Researches

Project

Distribution of loaches in the Tama River system, and seasonal movement and habitat use of the Japanese spined loach in a stream

Academic
Research
No.357
Principal
Investigator
Tomoko YOSHIKAWA
Affiliation College of Agriculture, Tamagawa University
Research
Summary

The distribution of loaches was surveyed in the Tama River system.Loaches were found in 68 out of 81 locations. More individuals were found in lower reaches. The introduced large-scale loach was not found in this survey. In the Hirai River, the reproductive season of the Japanese spined loach was from April to July, and the loach mainly preyed on chironomid larvae throughout the year. Juveniles stayed in shallow nearshore lentic water with vegetation cover and fine substrate. Large individuals stayed in shallow water with fine substrate during the spring spawning season. They moved to the center of the river in summer. Most loaches were found in shallow pools where water temperatures were higher than that of the mainstream in fall and winter. The tagged large individuals were found within 20-200m from the original point but small loaches tended to move downstream. The results showed that the spined loach has different microhabitat requirements in different seasons. Conservation measures should focus on creating habitat heterogeneity within small areas and providing shoreline vegetation or gabion banks as refuges from periodic freshets.


Collaborators

Akihiro YONEYAMA

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