Application of Logistic Curve as an Index of the Attractive Effect of Food for Oriental Weatherfish

Abstract

To obtain an index for the attractive effect of food, a logistic curve y_j=g/(1+e^-r(^j-a)), was applied to the time-courses, i.e. the observed y_j wiht the passing time from j=1 to 10min., for three behavior patterns (entered, left, and remained in the test compartment containing food) of oriental weatherfish Misgurnus anguillicaudatus. Of 28 (7 series×4 kinds of food) time-courses in each behavior pattern, and 27 (entered), 16 (left) and 27 (remained) time-courses fit the logistic curve with 0.10 level by chi-square test.
Among the nine coefficients (g, r and a for each behavior pattern), coefficient a of the logistic curve for the oriental weatherfish which remained in teh test compartment coincided with the general evaluation of the attractive effect. The following three reasons explain this coincidence: (1) this coeffcient reflects the average remaining time, (2) the evaluation by behavior was based on the average remaining time, the number of fish that remained, and their exploratory and feeding activity, and (3) the second and third criteria have a close relation to the first one.