in relatively restricted areas over a period of 18 

 mo. On one occasion only, fish (three individuals 

 released 4 h prior to recapture) that had been 

 previously tagged and released were recovered 

 again. Failure to relocate fish conventionally 

 tagged or fitted with transmitters could be the 

 result of factors other than fish leaving the gen- 

 eral area, such as mortality due to predation or 

 shock of capture and handling, or tag fail- 

 ures. However, none of the evidence gained in 

 this study suggests these factors were respon- 

 sible. 



The observed reduction in the proportion of 

 large bonefish present on the flats during warm- 

 water periods may correspond to a general 

 offshore movement in preparation for spawning. 

 Summer temperatures in the shallow areas of 

 Thrift Harbor Creek have exceeded 34 °C (Fig. 

 3). Although thermal requirements for Albula 

 vulpes have not yet been experimentally deter- 

 mined, abnormally high temperatures are 

 known to be deleterious to gamete formation 

 among vertebrates (Guyton 1976; Langman 

 1981). Among fishes, it has been generally estab- 

 lished that thermal requirements are even more 

 restrictive for the reproductive process than for 

 either growth or survival (Brett 1956). The 

 hypothesis that large bonefish move offshore 

 during summer is supported by the lore of the 

 local Bahamian fishermen. They believe that 

 larger individuals undergo a regular movement 

 into deeper (15-25 m) waters at this time. During 

 fall (October-November), these fish return 

 inshore and aggregate in large numbers to 

 spawn in shallow creeks. Erdman (I960 3 ) 

 reported a similar observation by commercial 

 fishermen in Puerto Rico. At the time of this in- 

 shore movement, the fish are said to be lighter in 

 color, with a highly silvery appearance. Personal 

 examination by the senior author of fish collected 

 by anglers from such aggregations revealed that 

 nearly all individuals were sexually ripe. Addi- 

 tional evidence of seasonal offshore movements 

 of bonefish comes from scuba divers in the Free- 

 port area (pers. commun.), who have reported 

 observing schools of thousands of bonefish sus- 

 pended above the reefs. Bohlke and Chaplin 

 (1968) cited a similar observation occurring 

 off the Tongue of the Ocean, Green Cay, Baha- 

 mas. 



3 Erdman, D. S. 1960. Notes on the biology of the bonefish 

 and its sports fishery in Puerto Rico. Paper prepared for the 

 5th Int. Game Fish Conf. Miami Beach, Fla., 11 p. 



Summary 



Bonefish appear to remain in a specific loca- 

 tion (e.g., creek, small bay, channel, etc.) for a 

 period usually not exceeding several days, and 

 then move on to other locations. While at a given 

 location, there is a distinct pattern to daily 

 movements in response to tidal fluctuations, but 

 long-term movements appear to be highly 

 variable, with no definable pattern seen. In 

 summer, larger individuals are rarely found on 

 the flats. Their reappearance in the fall concurs 

 with a rapid drop in water temperature at that 

 time of the year. 



Acknowledgments 



We gratefully acknowledge the generous fi- 

 nancial support of Perkin Sams, Mr. and Mrs. 

 Lewis Murdock, D. H. Ruttenburg, and the 

 Slocum-Lunz Foundation. The authors would 

 also like to thank the Murdocks, John Adams, 

 Richard Shaul, Patrick Pitts, Marie Colton, and 

 guides of Deep Water Cay Club for their assis- 

 tance in the field. We thank the Bahamian 

 Government for permission to conduct research 

 in their territorial waters. A very special thanks 

 to John and Ann Dickinson whose enthusiasm 

 and generosity made the field work possible. 



Literature Cited 



Bohlke, J. E., and C. C. G. Chaplin. 



1968. Fishes of the Bahamas and adjacent tropical 

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P- 

 Brett, J. R. 



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1974. Age, growth, food habits, and reproduction of bone- 

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COLLETTE, B. B., AND F. H. TALBOT. 



1972. Activity patterns of coral reef fishes with emphasis 

 on nocturnal-diurnal changeover. In B. B. Collette and 

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COUTANT, C. C. 



1975. Temperature selection by fish - a factor in power 

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DODSON, J. J., AND W. C. LEGGETT. 



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