72 



ICENDALL: NEW ENGLAND SALMONS. 



comparatively short time. Thus: a female kelt which, when marked January 18, 1902, 

 in the Tay, weighed 11 pounds and measured 38 inches, was recaptured as a clean 

 summer fish in the estuary of the Tay, August 20, 1902, having gained six pounds in 

 about seven months. As an example of very rapid growth in the Tay, Calderwood 

 cites a record of a kelt of 123/2 pounds, which doubled its weight in six months. 



The records of five fish could be cited, he says, of 8-12-pound kelts having increased to 

 19-25 pounds in from a year to a year and a half. One of these records is that of an 

 eight-pound kelt, 38 inches long, marked February 6, 1902, which on August 8, 1903, 

 was found to have gained 12Vio pounds and only 3^ inch in length in a Uttle over 13^^ 

 years. 



According to Calderwood the records indicate that there is considerable variation in 

 the matter of short and long periods of absence. That is to say, in some years the short- 

 period fish predominate or are more numerous than in other years. And again the long- 

 period fish are predominant to the extent of an entire absence of short-period fish. 

 Then again they may be approximately balanced. But he discounts the idea that these 

 facts are due to size of the fish. 



Calderwood also says that in spawning a female salmon loses approximately one- 

 fifth of its weight. From records of weights and measurements of kelts, Hutton (1922) 

 computed the loss in weight which the fish suffered from the time they entered the river 

 as clean fish to the time they returned to the sea as kelts. He gives the following figures: 



TABLE 6. 

 Weights of Clean Salmon and Kelts. 



'Therefore,' he says, 'In round figures a salmon will lose 15 per cent of its weight 

 between May and October, and a further 25 per cent during spawning, making a total 

 of 40 per cent before its returns to the sea as a kelt. 



'Assuming the above is correct,' he continues, 'the question naturally follows — what 

 increase may we expect in a salmon after its return to the river to spawn a second time? 

 This will depend upon two factors — first, the weight of the kelt, and second the period 

 spent in the sea.' Some kelts will adopt what Mr. Calderwood has aptly termed the 

 short-period of migration and will return to the river after spending only a few months 

 in salt water. 'Then again others will adopt the "Long-period", and will spend the 

 whole summer and the following winter in salt water and will return as Spring fish about 

 12 months after their descent as kelts. . . . We have also a third class, which I will 



