Different suitability of improved irrigation channels as reproductive sites for Cyprininae and Silurus asotus.

Irrigation channels around paddy fields have been drastically improved over the past several decades in Japan. This has been accomplished exclusively by covering all the sides of channels with concrete. Although it is conventionally accepted that channel improvement has deteriorated quality of spawning and nursery sites for fish, to date, there is little evidence to support this claim.

How Many Days in a Year Can Mt. Fuji and the Tokyo Tower Be Seen from the Tokyo Suburban Area?

Mt. Fuji and the Tokyo Tower were observed daily from the Seikei Meteorological Observatory in Tokyo for the past 30 years. The observatory recorded whether each object could be seen at 9:00 a.