HABITAT ANALYSIS OF PROCAMBARUS CLARKII IN LOTUS ROOT FIELDS IN NARUTO CITY, TOKUSHIMA PREFECTURE, JAPAN.

Abstract

 The purpose of this study was to determine the effects of local- and geographical-scale environmental factors on the distribution of Procambrus Clarkii to suggest a measure for expansion of this invasive species in the lotus root fields of Naruto City, Tokushima Prefecture. Field surveys were conducted for three times at each lotus field during June - July 2022. The analysis showed a significant relationship between water depth and vegetation cover of lotus fields in June, and percentage of concreted ridges in lotus fields in early July. The percentage of concreted ridges showed a weak negative relationship with the crayfish density in all three surveys, and no relationship was found between the population of American crayfish and geographical factors throughout the three surveys. These suggest that crayfish density is influenced by local environmental factors. Water management with keeping shallower depth during early developmental stage of lotus, and concreting ridges of lotus field might be potential measures on expanding the distribution of invasive crayfish.