Huntsman. — The Growth of Fishes 23 



the Bay of Fundy, from its having a higher bottom temperature 

 than have other parts of our Canadian eastern coast, promotes 

 the most rapid growth in this fish of which we have knowledge, 

 it is unfavorable for it in other ways, giving a slower growth in 

 later life, a lower maximum size, an earlier death, and no oppor- 

 tunity for successful breeding. 



We have perhaps surveyed the ground sufficiently to show 

 what an interesting and virgin field of research has been opened up 

 by these recently developed methods for the growth-study of 

 fishes. The importance of this work should be evident to every- 

 one. Much of our fishery legislation will be altered by the results 

 obtained in it, and it should show among other things beyond what 

 age it ceases to be profitable to leave the fish of a certain species in 

 the water, how intensively it is wise to fish a certain species, and 

 how long it should take for recovery from overfishing. 



(Read by Dr. E. E. Prince, Commissioner of Fisheries of Canada.) 



Discussion. 



Dr. E. E. Prince, of Canada: When Dr. Hjort, the Norwegian investi- 

 gator referred to in the paper, visited Canada and the United States, he did 

 some work for the Canadian Government. By studying the scales of the 

 sea-herring, he determined that some of these fish were actually twenty 

 years old. It seems remarkable that small fish, such as the sea-herring, 

 should reach that age. 



Dr. Huntsman was particularly interested in these studies of Dr. Hjort 

 and continued the investigation on the ear-bones or otoliths, which show 

 the growth year by year, and also on the rings of growth on the vertebrae. 

 He found some reason to question the determination of the age by the 

 scales alone. There should be a combination of all three kinds of 

 study to determine the age with accuracy. If a large number of fish from 

 any area are taken, you can almost determine how many years are repre- 

 sented in the mass, and when the earbones, scales and vertebrae confirm 

 this you can be certain as to the results. 



Mr. J. W. Titcomb, of New York: If I remember rightly, Dr. Hjort and 

 our U. S. Bureau of Fisheries are agreed that the scales behind the pectoral 

 fins, where there is no abrasion, are the ones to be used in determining the 

 age. 



Dr. Prince: That is a very good point. There is a certain amount of 

 wear and tear on the scales and they cannot be taken haphazard, but must 

 be selected from parts where there is the least abrasion. On some fish the 

 rings on the scales are so distinct and regular that the determination of the 

 age is more easy in some species than in others. 



