Formulation of preference intensity of field gudgeon to environmental factors for habitat assessment of agricultural canals
2007
Okushima, S.(National Inst. of Rural Engineering, Tsukuba, Ibaraki (Japan)) | Tanaka, Y. | Koizumi, N. | Takemura, T.
It is essential to give an environmental consideration into industrial or engineering techniques in farm land consolidation for the ecosystem conservation and for understanding the excellent native habitat for fishes around rice fields. However, the accumulation of knowledge on these issues is not enough. The present study aims to formulate preference intensity of field gudgeon with different growth stages of fry and adult by using laboratory open-channel experiments considering the four environmental factors of depth, Velocity, cover and vegetation. We employed the patterns of preference level with modified weighted product equation proposed by Sekine et. al (1994) for the formulation. As a result, the present models well represented the preference intensities of the fish in different growth stages. The preference weight of cover factor was found to be high in the fry and that of velocity and vegetation were high in the adult fish. It is suggested that the habitats with cover and vegetation are necessary for the field gudgeon and that low-velocity is the essential habitat especially for the fry.
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