Effects of connection of paddy fields, ditch and stream through small-scale fishways on fish fauna
2004
Suzuki, M. (Utsunomiya Univ. (Japan). Coll. of Agriculture) | Mizutani, M. | Goto, A.
Farm land consolidation projects that separate irrigation canal from drainage canal, especially those that dig deep drainage canals divide water area networks harm the habitat of freshwater fishes. This study examined the effects on fish inhabiting paddy fields, ditch and stream when these bodies of water were connected by small-scale fishways after farm land consolidation in Kawachi Town, Tochigi Prefecture. The following facts were revealed. 1) Misgurnus anguillicaudatus moved into the water area network through the small-scale fishways. 2) U-shaped concrete-lined provided a migration pathway for the fish. 3) Paddy fields connected by the small-scale fishways became reproduction fields for Misgurnus anguillicaudatus and Carassius. spp. and spital for the fishes in heavy rain. 4) Increasing drainage frequency facilitated the descent of fish from paddy fields. 5) Earth-lined ditch connected by small-scale fishways functioned as wintering fields for Misgurnus anguillicaudatus and reproduction fields for Pseudobagrus tokiensis.
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