Winter distribution pattern of Japanese eight-barbel loach in a conservation pond supplied with pumped groundwater

Abstract

The winter distribution pattern of Japanese eight-barbel loach Lefua echigonia, in a controlled groundwater input conservation pond, varied with changes in input the position, the loach population showing aggregated dispersion. The distribution pattern, apparently dependent upon groundwater-inflow, was shown by multiple regression analysis to be strongly influenced by water temperature. Aggregation of the loach at groundwater-inflow sites that were warmer than elsewhere in the pond may indicate avoidance of low winter water temperatures, illustrating the importance of spring water for this loach in the winter season.