FISHERY BULLETIN: VOL. 84, NO. 3 



These assumptions are implicit in the concept of 

 r-max. 



There is no evidence that the highest rates of in- 

 crease calculated here can be achieved by any real 

 dolphin population. Trade offs may exist between 

 survival and reproduction. Because of this, some of 

 the parameter combinations examined here are 

 probably unlikely, especially combinations of the ex- 

 treme values, i.e., those producing the highest rates 

 of increase. 



Although our figures also present minimum values 

 based on parameter combinations we used, we do 

 not believe that these will be useful in setting lower 

 bounds on finite rates of increase. Catastrophic 

 events can always lead to rapid extirpation of a 

 population. In fact, it is clear that dolphins (and 

 other animals with similar life histories) can 



c 

 o 



'■*-• 



o 



Q. 

 O 





 CO 



DC 



"cO 



> 

 > 



CO 



CO 



O 



0.95 0.97 



0.95 0.97 



0.85 0.90 0.95 0.97 



Noncalf Survival Rate (proportion) 



Figure 5.— First reproduction of dolphin age class 15 yr: a) 2-yr 

 calving interval (upper panel); b) 3-yr calving interval (middle 

 panel); c) 4-yr calving interval (lower panel). 



decrease in number much faster than they can 

 increase. 



ACKNOWLEDGMENTS 



This study benefited greatly from reviews by J. 

 Breiwick, D. Chapman, D. DeMaster, D. Goodman, 

 J. Hedgepeth, F. Hester, G. Sakagawa, D. Siniff, 

 T. Smith, and an anonymous reviewer. We sincere- 

 ly thank these people for their contributions. 



LITERATURE CITED 



Allen, K. R. 



1976. A more flexible model for baleen whale populations. 

 Rep. Int. Whaling Comm. 26: App. Report and Papers of 

 the Scientific Committee, p. 247-263. 



Barlow, J. 



1982. Methods and applications in estimating mortality and 

 other vital rates. Ph.D. Thesis, Univ. California, San Diego, 

 177 p. 

 Birch, L. C. 



1948. The intrinsic rate of natural increase of an insect 

 population. J. Anim. Ecol. 17:15-26. 

 Caughley, G. 



1977. Analysis of vertebrate populations. Wiley-Inter- 

 science, N.Y., 234 p. 



Eberhardt, L. L., and D. B. Siniff. 



1977. Population dynamics and marine mammal management 

 policies. J. Fish. Res. Board Can. 34:183-190. 



Essapian, F. S. 



1963. Observations on abnormalities of parturition in captive 

 bottlenosed dolphins, Tursiops truncatus, and concurrent 

 behavior of other porpoises. J. Mammal. 44:405-414. 

 Fruehling, J. A. (editor). 



1982. Sourcebook on death and dying. Marquis Prof. Publ., 

 Chicago, 788 p. 

 Goodman, D. 



1981. Life history analysis of large mammals. In C. W. 

 Fowler and T. D. Smith (editors), Dynamics of large mam- 

 mal populations, p. 415-436. Wiley, N.Y. 



JONSGARD, A., AND P. B. LYSHOEL. 



1970. A contribution to the knowledge of the biology of the 

 killer whale Orcinus orca (L.). Nytt. Mag. Zool. (Oslo) 

 18:41-48. 

 Kasuya, T. 



1976. Reconsideration of life history parameters of the 

 spotted and striped dolphins based on cemental layers. Sci. 

 Rep. Whales Res. Inst. Tokyo 28:73-106. 

 Kleinenberg, S. E. 



1956. Miekopitauishchenie Chernogo i Azovskogo Morei 

 (Mammals of the Black Sea and Sea of Azov). Akad. Nauk., 

 Moscow, 288 p. (Fish. Mar. Serv., Quebec, 1978, Transl. 

 ser. 4319, 428 p.) 

 Leslie, P. H. 



1945. On the use of matrices in certain population mathe- 

 matics. Biometrika 33:183-212. 



MlYAZAKI, N., AND M. NlSHIWAKI. 



1978. School structure of the striped dolphin off the Pacific 

 coast of Japan. Sci. Rep. Whales Res. Inst., Tokyo 30: 

 65-115. 



532 



