In which conditions do Far Eastern catfish (Silurus asotus) pursue their prey?

Abstract

Far Eastern catfish (Silurus asotus) are a top predator in Japanese freshwater ecosystems. The author used lure fishing on the Ooigawa-river, of the Biwako-Yodogawa basin system, to investigate the conditions in which the catfish pursue their prey. Using the catch number as the response variable, the data was analyzed by GLM (generalized linear model) and model selection with AIC (Akaike’s information criterion). The explanatory variables were the time of day, weather, average temperature, maximum wind speed, precipitation of the previous day, atmospheric pressure, and the moon phase. Detention time was the offset value in order to standardize the survey time variable. Results indicated that two variables, weather and the maximum wind speed, were selected by GLM using AIC. It is suggested that the capture of S. asotus tended to increase with more severe weather conditions.