Study on Water Environment and Fish Behavior in Agricultural Canals

对于农业运河生态系统的保护和恢复，重要的是不仅要量化优选栖息地的特性，如水质和水力条件，而且鱼类或野生动物的环境偏好。本研究通过实验室试验和现场调查，对日本青鳉的环境偏好性和农业水渠水环境进行了研究。选择日本青鳉鱼作为研究对象，是因为日本青鳉鱼被认为是日本农村生态系统恢复的象征性鱼类。通过对近年来在农业水渠中建造的鱼巢人工砌块及其周围的水力测量，分析了水深、水深、鱼巢密度、鱼密度、鱼巢密度、鱼流速和覆盖被选为影响agr鱼类栖息地的可用性和质量的主要因素。 关于我们 文化运河基于鱼类的行为本质上是不承诺的，以及对环境变化的行为反应在个体和环境之间存在很大差异的背景下，日本青鳉对三种环境因子的偏好强度通过模糊逻辑建模和实验室明渠实验进行了量化。引入一种简单的遗传算法来搜索偏好强度的最优函数表示。模糊遗传算法偏好强度模型，然后成功地验证了实验室水槽实验和现场检查。在考虑流速和覆盖度这两个因素的情况下，预测值与实测值的分布吻合较好，表明流速和覆盖度这两个因素明显影响了日本青鳉的环境偏好。个体之间的距离，个体的空间分布和沟通过程。引入行为模式模型和人工网络模型来描述鱼群集群行为。利用该模型进行的数值模拟结果在偏振度、最近邻距离、膨胀度和分维等方面与实验结果基本一致。通过计算游泳轨迹、游泳速度和转身角度的回归图、分形维数、关联维数和小波变换，量化了个体间游泳行为的差异。利用计算结果对特定环境中鱼类的张力或休息程度的评估以及基于鱼类的水环境化学污染物生物监测的可行性进行了验证。少

For the preservation and restoration of ecosystems in agricultural canals, it is important to quantify not only the characteristics of preferable habitat such as water quality and hydraulic condition but also environmental preference of fish or wildlife. In this research, environmental preference of Japanese Medaka Fish (Japanese killifish, Oryzias latipes) and water environments in agricultural canals were investigated by laboratory experiments and on-the-spot examinations. Japanese Medaka Fish was selected as a river fish subject to this research because Japanese Medaka is now regarded as the symbolic fish for the restoration of countryside ecosystems in Japan.Judging from the hydraulic measurements in and around artificial blocks that are recently constructed for providing fish nest in agricultural canals, the three environmental factors of water depth, current velocity and cover were selected as the principal factors affecting the availability and quality of the fish habitat in agr … More icultural canals. Based on the background that fish behavior is essentially noncommittal and that the behavioral responses to an environmental change vary widely among both individuals and circumstances, the preference intensities of Japanese Medaka to the three environmental factors were quantified by fuzzy logic modeling and laboratory open-channel experiments. A simple genetic algorithm was introduced to search for the optimal functional representation of preference intensity. The fuzzy-GA preference intensity model was then successfully verified by laboratory water-tank experiments and on-the-spot examinations. The good agreement between the predicted and observed distributions in considering the two factors of current velocity and cover indicated that the two factors obviously affected the environmental preferences of Japanese Medaka.For the purpose of evaluating the water environment of fish habitat through the individual-based model approach, the schooling behavior of Japanese Medaka was analyzed to determine the interactions between individuals: the spacing between individuals, the spatial distribution of individuals and the communication processes. The behavioral pattern model and the artificial network model were introduced to describe the behavior of fish schooling. The results of the numerical simulations using the models agreed with the experimental data in many regards, including the polarization, the nearest neighbor distance, the expanse and the fractal dimension. The differences of swimming behavior among individuals were also quantified by calculating return map, fractal dimension, correlation dimension and wavelet transform for swimming trajectory, swimming velocity and turning angle respectively. The feasibility of the assessment for the degree of tension or rest of fish in specific environment and the fish-based biomonitoring for chemical contaminants in water environment was examined using the calculated results. Less