This volume is a compilation of the papers presented at a meeting that took place in April 1980 at the Mote Marine Laboratory, Sarasota, Florida The meeting and this volume are outgrowths of two earlier international meetings on marine bio-acoustics that occurred in 1963 and 1966 (Tavolga 1964, 1967) The first meeting took place at the Lerner Marine Laboratory of the American Museum of Natural History, while the second meeting was at the American Museum itself, and was under the sponsorship of the Department of Animal Behavior It is apparent that these two volumes have had immense impact on the current study of marine bio-acoustics, and particularly on fish audition In a preliminary conference in Sarasota in 1979 we decided that it was time for another such meeting, to bring together as many as possible of the investigators interested in fish acoustics in order to assess the current state of our knowledge and predict directions for research for the next several years Such a meeting appeared par ticularly timely, since over the past four or five years there have been many new studies that have provided new empirical and theoretical work on basic mechanisms of fish audition Furthermore, it became evident, as we made up preliminary lists of possible participants, that few of the currently active workers were in the field back in 1966 In fact, of the current participants, only Drs"

Hearing and Sound Communication in Fishes

A most intriguing aspect of social behavior is that eventually the topic of communication must be addressed. This is understandable because specific acts performed by one individual often alter the likelihood that specific acts will be performed by another. An appropriate question then arises: Did such a performance involve communication? Here, the thoughtful worker often encounters a most elusive concept since “communication” means quite different things to different people.

Sound Communication and Interception in Fishes

Many underwater bioacoustical recording experiments (e.g., fish sound production during courtship or agonistic encounters) are usually conducted in a controlled laboratory environment of small-sized tanks. The effects of reverberation, resonance, and tank size on the characteristics of sound recorded inside small tanks have never been fully addressed, although these factors are known to influence the recordings. In this work, 5-cycle tone bursts of 1-kHz sound were used as a test signal to investigate the sound recorded in a 170-l rectangular glass tank at various depths and distances from a transducer. The dominant frequency, sound-pressure level, and power spectrum recorded in small tanks were significantly distorted compared to the original tone bursts. Due to resonance, the dominant frequency varied with water depth, and power spectrum level of the projected frequency decreased exponentially with increased distance between the hydrophone and the sound source; however, the resonant component was nearly uniform throughout the tank. Based on the empirical findings and theoretical calculation, a working protocol is presented that minimizes distortion in fish sound recordings in small tanks. To validate this approach, sounds produced by the croaking gourami (Trichopsis vittata) during staged agonistic encounters were recorded according to the proposed protocol in an 1800-l circular tank and in a 37-l rectangular tank to compare differences in acoustic characteristics associated with tank size and recording position. The findings underscore pitfalls associated with recording fish sounds in small tanks. Herein, an empirical solution to correct these distortions is provided.

Empirical refinements applicable to the recording of fish sounds in small tanks.

Sound production by males of a coral reef fish (Pomacentrus partitus): its significance to females

This paper reviews the variety of approaches available to fish ethologists to study the role of visual cues in fish behavior. Examples of studies that have used live fish, mirror images, dummies (i.e. models), or video playback as stimuli to investigate fish behavior are described and discussed. These examples represent a diversity of functional categories of behavior exhibited by fishes, including aggression, courtship, aggregation, or schooling behavior, parent–offspring, predator–prey, and cleaner–host interactions. The specific techniques that fish biologists have used to control or manipulate body shape, size, posture, morphological structures, color, marking patterns, or movement are systematically discussed, and the importance of each of these visual features to fish behavior is documented through examples. Studies that have used these techniques to investigate the interaction between visual and nonvisual cues are also considered. Each section encompassing a general experimental approach ends with a discussion of the advantages and disadvantages of that approach for studying fish behavior.

Studying visual cues in fish behavior: a review of ethological techniques

Field and laboratory observations were made on the reproductive behavior, ecology and sounds produced by males of Notropis analostanus during reproductive behavior. Based on these observations, experiments were performed on sound communication during the repro- ductive behavior of this species. Reproductive activities began in middle to late May when the males set up territories around a suitable egg site. The males defended these territories by chasing and fighting behavior which included the lateral threat display. During this aggressive behavior, "single knocks" and "rapid series of knocks" were produced. Courtship behavior began when a female approached the territory and the male swam out to her. If the female did not swim away, the male swam in circles around her and then swam to the egg site where it would perform "solo-spawning" motions. Spawning was accomplished when the female followed the male to the egg site and assumed a spawning position with the male in a dorsolateral position to her. During the courtship behavior the male produced "single knocks" and "purrs." The functions of sounds produced by male Notropis analostanus during reproductive behavior were studied by playing back these sounds under experimental conditions designed to clarify their functions as com- municative signals. The following conclusions were reached: 1. The "single knocks" were not effective in influencing aggressive behavior of males nor did they promote courtship. 2. The "rapid series of knocks" stimulated aggressive behavior by a dominant male and inhibited the entry of a submissive male into the territory. 3. The "rapid series of knocks" inhibited the courtship behavior of the male and reduced cooperation by the female during courtship. 4. The "purrs" increased the courtship behavior of the male and pro- moted the cooperation of the female during courtship.

John F. Stout

Papers

Sound Communication During the Reproductive Behavior of Notropis analostanus (Pisces: Cyprinidae)