Reproductive ecology of endangered freshwater salmonid fish, Sakhalin taimen (Hucho perryi) in one of the subsidiary streams of Kushiro River basin, eastern Hokkaido, Japan: Spawning period, number of redds and the characteristic of their distribution in the 2006 research
2009
Kasai, F.(Tokyo Univ. of Agriculture, Abashiri, Hokkaido (Japan)) | Tanaka, S. | Komiyama, E. | Natsuhara, N. | Mizuguti, T.
The Sakhalin taimen, Hucho perry, is the biggest freshwater fish, and one of the endangered species in Japan. We studied reproductive ecology of this fish in one of the subsidiary streams of Kushiro River, eastern Hokkaido. In the study, the spawning period lasted for 37 days from April 1 to May 7. Redds were 65 and the water temperature was from 0.9 to 7.0 degrees Celsius. It is reported that this fish starts spawning at the end of April, the spawning period lasts for 7 to 14 days and the water temperature during spawning term is 3 to 7 degrees Celsius in the rivers in the middle and north of Hokkaido. However, in the river where we conducted this research in the east of Hokkaido, it was observed that the spawning of the fish started about three weeks earlier than the fish in the rivers in the middle and north of Hokkaido that the spawning period was longer and that the spawning started when the water temperature was still low. It could be estimated that this is because the amount of snow in this area is comparatively small than that of the other areas and the climate conditions and river environment in the melting season differ.
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