A stochastic model for behaviour of fish ascending an agricultural drainage system

作者：Unami Koichi^*; Ishida Kei; Kawachi Toshihiko; Maeda Shigeya; Takeuchi Junichiro

来源：Paddy and Water Environment, 2010, 8(2): 105-111.

DOI：10.1007/s10333-009-0189-3

• Continuous Markov process
• Carassius auratus grandoculis
• Agricultural drainage systems
• Computational methods

Adults of Carassius auratus grandoculis ascend from Lake Biwa, Japan, into riparian paddy fields via agricultural drainage systems for the purpose of spawning. However, land improvement works conducted in the second half of the twentieth century have brought about obstacles for passage of the fish, and several restoration projects to recover the migratory environment are being attempted. A continuous Markov process model is presented to scientifically support such a project, defining an ascending probability that quantitatively assesses the ability of an agricultural drainage system with hydraulic structures for the ascent of the fish. Computational methods are developed to numerically obtain flow fields of the agricultural drainage system and then the ascending probability in the entire spatio-temporal domain. The values of model parameters are deductively inferred, referring to results of field observations. From the computational results of the ascending probability in the agricultural drainage system, effects of hydraulic structures allowing ascent of the fish are clarified.

• 出版日期2010-6