and biological factors control motivation during 

 the season. An unspawned male and a once- 

 spawned male guarding eggs, might call at differ- 

 ent rates. Schwartz (1974) and Lowe (1975) have 

 indicated spawning peaks, which could be related 

 to calling motivation. Although calling decreases, 

 boatwhistles are still emitted after the assumed 

 mating season (Fine 1976) It is not possible to 

 accurately place the perud of 9-15 June 1969 in a 

 spawning peak or lull. 



Density within a toadfish population will also 

 affect sound production since calling fish facilitate 

 each other. There could also be a tonic facilitation 

 (Schleidt 1973), so that fish hearing boatwhistles, 

 even if below the stimulatory rate, would be more 

 prone to call than would a solitary male. It is also 

 possible that some populations of toadfish could be 

 limited by shelter availability for male nesting. At 

 the dock at Solomons, where these recordings were 

 made, shelter was provided primarily by our tiles 

 placed along the dock pilings. Since the area was 

 largely clear of rocks, tin cans, and boards which 

 might provide shelter, the density of calling fish in 

 the experimental area was not high, and we might 

 not expect a great deal of facilitation. 



Acknowledgments 



This investigation was supported by the Office 

 of Naval Research through contract N000 14-68- 

 A-0215-0003 under project NR 083-165. 



Literature Cited 

 Breder, C. M., Jr. 



1968. Seasonal and diurnal occurrences offish sounds in a 

 small Florida Bay. Bull. Am. Mus. Nat. Hist. 138:327- 

 378. 

 BRIGHT, T. J. 



1972. Bio-acoustic studies on reef organisms. In B. B. 

 Collette and S. A. Earle (editors), Results of the Tektite 

 program: Ecology of coral reef fishes, p. 45-69. Bull. Nat. 

 Hist. Mus. Los Ang. Cty. 14. 

 BRIGHT, T. J., AND J. D. SARTORI. 



1972. Sound production by the reef fishes Holocentrus 

 coruscus, Holocentrus rufus, and Myripristis jacobus fam- 

 ily Holocentridae. Hydro-Lab J. 1:11-20. 

 FINE, M. L. 



1976. Variation of natural and brain-stimulated sounds of 

 the oyster toadfish Opsanus tau L. Ph.D. Thesis, Univ. 

 Rhode Island, Kingston, 70 p. 



Fish, J. F. 



1972. The effect of sound playback on the toadfish. In 

 H.E. Winn and B. L. Olla (editors), Behavior of marine 

 animals: current perspectives in research. Vol. 2. Verte- 

 brates, p. 386-434. Plenum Press, N.Y. 

 FISH, J. F., AND G. C. OFFUTT. 



1972. Hearing thresholds from toadfish, Opsanus tau, 



measured in the laboratory and field. J. Acoust. Soc. Am. 

 51:1318-1321. 

 FISH, M. P. 



1954. The character and significance of sound production 

 among fishes of the western North Atlantic. Bull. Bing- 

 ham. Oceanogr. Collect. Yale Univ. 14(3), 109 p. 



Gray, G. a., and h. e. winn. 



1961. Reproduction ecology and sound production of the 

 toadfish, Opsanus tau. Ecology 42:274-282. 

 LOWE, T. P. 



1975. Reproductive ecology of oyster toadfish (Opsanus 

 tau) in Charlestown Pond, Rhode Island. Ph.D. Thesis, 

 Univ. Rhode Island, Kingston, 120 p. 



Salmon, M. 



1967. Acoustical behavior of the menpachi, Myripristis 

 berndti, in Hawaii. Pac. Sci. 21:364-381. 

 SCHLEIDT, W. M. 



1973. Tonic communication: continual effects of discrete 

 signs in animal communication systems. J. Theor. Biol. 

 42:359-386. 



SCHWARTZ, F. J. 



1974. Movements of the oyster toadfish (Pisces: Ba- 

 trachoididae) about Solomons, Maryland. Chesapeake 

 Sci. 15:155-159. 



Schwartz, F. j., and p. F. Robinson. 



1963. Survival of exposed oyster toadfish and biological 

 clocks. Prog. Fish-Cult. 25:151-154. 



TA VOLGA, W. N. 



1958. Underwater sounds produced by two species of 

 toadfish, Opsanus tau and Opsanus beta. Bull. Mar. Sci. 

 8:278-284. 

 1960. Sound production and underwater communication 

 in fishes. In W. E. Lanyon and W. N. Tavolga (editors), 

 Animal sounds and communication, p. 93-136. Am. 

 Inst. Biol. Sci. Publ. 7. 

 WINN, H. E. 



1964. The biological significance offish sounds. In W. N. 

 Tavolga (editor), Marine bio-acoustics, p. 213-231. Perg- 

 amon Press, N.Y. 



1967. Vocal facilitation and the biological significance of 

 toadfish sounds. In W. N. Tavolga (editor), Marine bio- 

 acoustics. Vol. 2, p. 283-304. Pergamon Press, N.Y. 

 1972. Acoustic discrimination by the toadfish with com- 

 ments on signal systems. In H. E. Winn and B. L. Olla 

 (editors), Behavior of marine animals: current perspec- 

 tives in revol. 2. Vertebrates, p. 361-385. Plenum Press, 

 N.Y. 

 Winn, H. E., J. A. Marshall, and B. Hazlett 



1964. Behavior, diel activities, and stimuli that elicit 

 sound production and reactions to sounds in the longspine 

 squirrelfish. Copeia 1964:413-425. 



Michael L. Fine 



Section of Neurobiology & Behavior 

 Cornell University 

 Ithaca, NY 14853 



Howard E. Winn 



Linda Joest 



Paul J. Perkins 



Graduate School of Oceanography 

 University of Rhode Island 

 Kingston, RI 02881 



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