F. DAY: PERIODS OF MIGRATION. 



127 



grounds. This question of rapidity of ascent is one by no means 

 settled, while it is of the greatest consequence to the upper riparian 

 proprietors. Mr. Willis-Bund considers that in the Severn they go 

 up stream very leisurely, as two or three miles an hour ; consequently, 

 in a river having a long course, the weekly close time merely changes 

 the locality where they are captured, for he believes none attain to 

 the upper waters during the netting season. As a corroboration of 

 this, it is observed that, except under exceptional conditions, it is 

 some days after the nets are off rivers before the upper proprietors 

 have much chance of hooking a fish. 



Livingston-Stone remarked that 'it frequently happened that a 

 whole run of salmon for several days will be composed almost entirely 

 of males, the effect of which, of course, is to leave the females 

 together by themselves, whether they take an active part or not in 

 bringing about the separation. In fact, in hauling a seine frequently 

 in a river for some time, it is generally very noticeable that the sexes 

 alternate in running up the river about the spawning season, a large 

 body of males being followed by a large body of females, and these 

 by a run of males again, and so on through the season ' (Bull ; 

 U.S. Fish. Com., 1885, p. 468). Mr. Willis-Bund has also observed 

 ' that the male fish swims up the river more quickly than the female ; 

 at all events, the higher up the river the netting takes place, the 

 greater percentage of males to females caught' ('Salmon Problems,' 

 page 156). 



In their course up stream it is very remarkable what difficulties they 

 will overcome. Fleming asserted that he had known a salmon leap up 

 over a fall of 30 ft., but probably he intended to mean in a succession 

 of jumps from one pool or resting-place to another. Twiss ('Travels in 

 Iceland ') declared that from personal observation he knew they were 

 able to dart themselves nearly 14 ft. perpendicularly out of the water. 

 Professor Landmark has stated {Nature, August 6th, 1885) that be 

 had witnessed their jumping 16 ft. perpendicularly, but continued, 

 'Such jumps are rare.' Scrope, after making a number of observations, 

 came to the conclusion that 6 ft. or 7 ft. came nearer the truth. At 

 impassable cascades they have been observed to die, consequent upon 

 repeated but fruitless exertions in attempting to ascend. 



In the Severn it has been observed that after the exertion of 

 crossing a weir or ascending a rapid, they take a rest ; for the best 

 draught of these fish are captured above the obstruction in the dead- 

 water. Kelts, when obstructed in their course down a river, strike 

 up stream ; thus, we are told that at Powick weir, which solely 

 captures ascending fish, kelts are often taken in the spring, and 

 usually when there is a slight fresh in the river. 



April 1886. 



