1.5 



1.4 



1.3 



1.2 



I.I 



1-0. 



4 5 



R/L 



Figure 2. — Ratio of minimum speed when moving in a circular 

 path, to the minimum speed in straight-line swimming versus 

 the ratio of turning radius to fish length, for skipjack tuna, 

 Katsuwonus pelamis. 



skipjack tuna, for which m = 0.00490L^^^ and A/- 

 = 0.00749L^^^, so that a slight dependence on fish 

 length is retained, even after normalizing by the 

 length. These curves can now be used to establish 

 the increase in minimum energy consumption, 

 with the aid of Equation (26). 



In conclusion, it is seen that running fish in 

 circular tanks can cause very significant addi- 

 tional stresses. These have to be taken into ac- 

 count when applying data collected under such 

 circumstances to naturally occurring situations. 



Literature Cited 



Bainbridge, R. 



1958. The speed of swimming offish as related to size and 

 to the frequency and amplitude of the tail beat. J. Exp. 

 Biol. 35:109-133. 

 BROWN, C. E., AND B. S. MUIR. 



1970. Analysis of ram ventilation offish gills with applica- 

 tion to skipjack tuna (Katsuwonus pelamis) . J. Fish. Res. 

 Board Can. 27:1637-1652. 

 Fry, F E. J. 



1957. The aquatic respiration of fish. In M. E. Brown 

 (editor). The physiology of fishes. Vol. I, p. 1-63. Acad. 

 Press, N.Y. 

 hoerner, S. F 



1965. Fluid-dynamic drag. Practical information on 

 aerodynamic drag and hydrodynamic resistance. Pub- 

 lished by the author, Midland Park, N.J. 



MAGNUSON, J. J. 



1970. Hydrostatic equilibrium of Euthynnus affinis, a 

 pelagic teleost without a gas bladder. Copeia 1970: 

 56-85. 



1973. Comparative study of adaptations for continuous 

 swimming and hydrostatic equilibrium of scombroid and 

 .xiphoid fishes. Fish. Bull., U.S. 71:337-356. 



1978. Locomotion by scombrid fishes: hydromechanics, 

 morphology, and behavior In W H. Hoar and D. J. Ran- 

 dall (editors). Fish physiology Vol. 7, p. 239-313. Acad. 

 Press, N.Y 

 NAKAMURA, E. L., and J. H. UCHIYAMA. 



1966. Length-weight relations of Pacific tunas. In T. A. 

 Manar (editor). Proceedings of the Governor's Conference 

 on Central Pacific Fishery Resources, Honolulu — Hilo, 

 February 28-March 12, 1966, p. 197-201. State of Hawaii, 

 Honolulu. 



neill, w. h., r. k. c. Chang, and a. e. dizon. 



1976. Magnitude and ecological implications of thermal 

 inertia in skipjack tuna, Katsuwonus pelamis (Lin- 

 naeus). Environ. Biol. Fishes 1:61-80. 

 WEBB, P W. 



1975. Hydrodynamics and energetics of fish propul- 

 sion. Fish. Res. Board Can., Bull. 190, 158 p. 



DANIEL WEIHS 



Southwest Fisheries Center Honolulu Laboratory 



National Marine Fisheries Service, NOAA 



Honolulu, Hawaii 



Present address: Department of Aeronautical Engineering 



Technion — Israel Institute of Technology 



Haifa, Israel 



Acknowledgments 



This study was done while I was a Visiting Sci- 

 entist at the Southwest Fisheries Center Honolulu 

 Laboratory, National Marine Fisheries Service, 

 NOAA, Honolulu, Hawaii. I would like to thank 

 Andrew E. Dizon and Randolph K. C. Chang for 

 their hospitality and helpful comments, and P W. 

 Webb for critically reading a previous version of 

 the manuscript. 



176 



