28 



F. DAY: EARLY AND LATE SALMON RIVERS. 



is to investigate our salmon should ascertain whether they are annual 

 or biennial breeders. 



As to the constitutional peculiarities of an early or late race, 

 although summarily dismissed by several authors, it does not appear 

 improbable that such may exist. Many excellent observers have 

 held that the descendants of early-ascending fish would similarly 

 give rise to a race having the same peculiarity. And if this early 

 habit is capable of transmission to offspring, it would be sound 

 economy to stock a late river with an early breed, in order to try and 

 convert it from a late into an early one. At the same time attention 

 must be drawn to the fact that it has not been proved that it is the 

 early breeders that produce the early ascending fish,* and it has still 

 to be shown whether the parents of these early forms do not deposit 

 their milt and ova at the same time as salmon whose descendants 

 have the late instincts ; while I have already drawn attention to the 

 want of evidence respecting the condition of the early ascending fish 

 as regards their fertility or sterility. The Commissioners in 1861 

 concluded that as to 'the alleged difference of season in certain 

 rivers, we think that artificial causes have much more concern in 

 producing such anomalies, than the laws of nature, ... In 

 order to enable the upper waters to be fully stocked, it is necessary to 

 afford a free run to the early spawning fish, which are naturally 

 impelled to seek the highest parts of the stream to breed in. If, 

 however, in consequence of an undue extension of the fishing season, 

 these fish are cut off in their passage up, it follows that no stock will 

 be left to replenish the river, except those later fish which 

 make their ascent under the protection of the close time. It is in 

 this way that some rivers are artificially made later, and the fact 

 accounted for 5 (page xxviii). Professor Huxley seems to consider 

 that, just as the capture of the early fish in early rivers has not tended 

 in the least degree to make them late, so the preservation of the late fish 

 in the very late rivers has not tended to make them later than they 

 were.' ' I cannot say,' he continues, ' that I can discover any good 

 ground for the belief that any kind of human interference is competent 

 to affect the earliness or lateness of a river. Differences in the habits 

 of fish in the same river have been and are still observed where the 

 artificial conditions are constant'; and he instances weirs, but denies 

 that their presence has altered the inherited instincts of these fish as 

 to their times of ascent. 



Mr. Pike, secretary to the Dart Fishery Board, remarked in 

 Land and Water, March 28th, 1885, that the Totnes Weir 



* The Commissioners for 1861 observe : ' Experience has fully proved the fact 

 in Ireland, where the enforcement of an earlier closing season has produced within 

 a few years a corresponding early supply in certain rivers ' (page xxviii). _____ 



Naturalist, 



