158 R. M. LAWS 



(5) Recruitment is within narrow limits related to the size of the adult 

 female component of the population. 



(6) The pregnancy rate of mature females has increased in response to 

 exploitation and the age at maturity is now earher, possibly in association 

 with an increase in the growth rate. 



(7) In spite of the increased reproductive rate survival curves indicate that at 

 the present rate of exploitation recruitment is insufficient to maintain the 

 stocks. 



REFERENCES 



Brown, S. G. (1954). Dispersal in blue and fin whales. Discovery Rep., 26, 355-84. 



HjORT, J., Lie, J. & Ruud, J. T. (1932). Norwegian pelagic whaling in the Antarctic. L Whaling 



grounds in 1929-1930 and 1930-193 1. Huahad. Skr., 3, 1-37. 

 HjORT, J., Lie, J. & Ruud, J. T. (1933). Norwegian pelagic whaling in the Antarctic. II. HvalrM. 



Skr., 7, 128-52. 

 Hylen, a., JonsgArd, A., Pke, G. C. & Ruud, J. T. (1955). A preHminary report on the age 



composition of antarctic fin whale catches 1945/46 to 1952/53 and some reflections on total 



mortality rates of fm whales. Hualfangst-tidende, 1955, 10, 577-89. 

 International Whaling Statistics (1930-1959). 

 Laws, R. M. (1958). Recent investigations on fin whale ovaries. Hvalfangst-tidende, 1958, 5, 



225-54. 

 Laws, R. M. (1959^). Age determination of whales by means of the corpora albicantia. XVth. 



Internat. Congr. ZooL, Proceedings, 303-5. 

 Laws, R. M. (1959^). Accelerated growth in seals with special reference to the Phocidae. 



Hvalfangst-tidende, 1959, 9, 425-52. 

 Laws, R. M. (in press). Reproduction, growth, and age of southern fin whales. Discovery Rep.^ 



31, 327-486. 

 Mackintosh, N. A. (1942). The southern stocks of whalebone whales. Discovery Rep., 22 



197-300. 

 Mackintosh, N. A. & Brown, S. G. (1956). Preliminary estimates of the southern populations 



of the larger baleen whales. Hvalfangst-tidende, 1956, 9, 469-80. 

 PURVES, P. E. (1955). The wax plug in the external auditory meatus of the Mysticeti. Discovery 



Rep., 27, 293-302. 

 PuRVES, P. E. & MouNTFORD, M. D. (i959). Ear plug laminations in relation to the age composi- 

 tion of a population of fm whales {Balaenoptera physalus). Bull. Brit. Mus. (nat. Hist.), Zoology, 



No. 6, 123-61. 

 Ruud, J. T. (1945). Further studies on the structure of the baleen plates and their application to 



age determination. Hvalrad. Skr., 29, 1-69. 

 Wheeler, J. F. G. (1934). On the stock of whales at South Georgia. Discovery Rep., 9, 351-72. 



