魚類の聴覚特性に関する研究-I

Abstract

The author considered the auditory characteristic in a lateral line of fish and calculated it on the physiological data about Carassius auratus (Body length; about 20cm.: Absolute refractory periods; 3 milli-sec. in A-neuron and 11 milli-sec. in B-neuron: Transmitting verocities of stimulation; 28.9m/sec. in A-neuron and 6.5m/sec. in B-neuron). The results got are as follow: a) When there is a sound-source in the elongate direction of body-axis, the upper limit of audible frequency may be about 7500 c/sec. and the most sensitive frequency is about 160 c/sec. In this case, the influence of the distance between the sound-source and the fishbody on the range of audible frequency is negligible. b) When there is the sound-source in the vertical direction against body-axis, the influence of the distance between the source and the body on the range of audible frequency is serious. For an example, although the most sensitive frequency is about 710 c/sec, at one meter distance, the most sensitive one is about 1300 c/sec. at a long (1000m.) distance. c) There is not the lower limit of audible frequency. It seem that the audible frequency may be lower as the sound-pressure becomes higher almost independently of the distance between the source and the body. Then, in experiments about the auditory characteristic of fish, we must be careful for the definitions of a sound-source position against fish-body and of the intensity of sound-pressure. Especially, as the sound in a small aquarium causes its reflections, interferences and -transmissions through walls, the devices to suppress them must be adopted so as to gain clear effects or correct results., The author is studying about aquaria with walls isolated from the influences of sound.