Full Description

"On listening to tape recordings we can clearly distinguish two types of acoustic signals: drumming sounds consisting of low-frequency pulses, and the sounds of the anchovy—infrequent high frequency cracklings."

"There is a considerable increase in the level and frequency of the high frequency sounds which is apparently an indication of the excited state of the anchovies approaching the light source. The nature of the drumming sounds also alters slightly when the light is switched on. There is a reduction in the number of loud sounds, but on the whole the nature of this type of sound emission alters only slightly."

Observation Environment Quotes

"The study was conducted in March 1970 in the southeastern part of the Black Sea on wintering aggregations of anchovy. The ex- periments were conducted simultaneously from two vessels: the medium range fishing trawler SRT K. Boldyrev equipped with fish-locating devices, underwater light sources, a Japanese RF-605 echosounder and an APT-2P underwater television camera, and the research vessel Ingur equipped with sound recording equipment and capable of operating under conditions of quietness."

Sound Name Quotes

"On listening to tape recordings we can clearly distinguish two types of acoustic signals: drumming sounds consisting of low-frequency pulses, and the sounds of the anchovy—infrequent high frequency cracklings."

Full Description

"Oscillograms of the acoustic signals of L. delineatus before (a) and after (b) the light was switched on are reproduced in Fig. 4. L. delineatus emits sounds very infrequently in total darkness. A sharp increase in the acoustic activity of L. delineatus is noted when the light source is switched on and the fish move actively toward the source (Fig. 4, b)."

Observation Environment Quotes

"With the object of verifying the data obtained under field conditions, similar experiments were conducted in the laboratory on Leucaspius delineatus Heck. A small group of 50 L. delineatus was placed in a long glass tank, one end of which was lit by a filament lamp. The fish were kept in darkness for 3 minutes, after which the light source was switched on. The acoustic activity of L. delineatus was measured before and when the lamp was switched on in the same way as in the experiments with the anchovy."