LIFE HISTORY: METHODS OF STUDY. 51 



of any other river, at a considerable distance from the shore. In the case of the quinnat 

 and the blueback, their "instinct" seems to lead them to ascend these fresh waters, and, 

 in a majority of cases, these waters will be those in which the fishes in question were 

 originally spawned.' 



In comparatively recent marking experiments by J. A. Rodd (1917), Superintendent 

 of Fish Culture, Canada, the fish were all taken as clean-run fish, retained in ponds, 

 stripped, weighed, tagged and liberated. Practically all of the recaptures were in the 

 vicinity of the place where first taken ; even those at a distance were in the same general 

 region. 



In Maine, notwithstanding the fact that the rivers in which salmon can to any extent 

 spawn and that the only salmon hatchery is in Penobscot waters, for many years oc- 

 casional salmon have appeared in streams not now usually frequented by them and 

 which they are unable to ascend. Early mentions are of the Saco, Presumpscot, Andro- 

 scoggin, and Kennebec, where the appearance of an individual below a dam has been 

 noted. In some of the eastern smaller streams a few salmon are taken almost every year. 



The foregoing evidence is by no means exhaustive, either way, but it seems sufficient 

 to indicate clearly that naturally each salmon river was frequented by a sufficient number 

 of salmon each year, which were bred in the river, and not enough of migrants from other 

 birth places entered them to prevent the estabhshment of somewhat differing races, 

 pecuUar to their respective streams. In more widely separated regions, as New England 

 and Labrador, for instance, it is quite possible, if not to say probable, that the salmon 

 differ so much physiologically in conformity to the conditions, that those from one 

 locality can not be successfully acclimatized in the other. 



Life History of the Salmon. 

 Methods of Study. 



As previously remarked G. Brown Goode (1884, p. 469) wrote, 'At least half of the 

 salmon's life is spent in the ocean.' This is a generalization which does not hold true in 

 all instances, yet the exceptions perhaps may prove the rule. As will be seen later in 

 some locahties a great many salmon spend much more than half their lives in the rivers. 

 The fife of a salmon begins in the river where as a young fish it remains until it descends 

 to the sea. After residing and feeding in the sea for one or more years it returns to the 

 river with the ultimate purpose of propagation. 



In connection with the general phenomenon of the anadromous migrations the seasonal 

 runs of salmon presented a problem to early investigators which gave rise to much dis- 

 cussion and various theories. Rivers were denominated as 'early' and 'late' rivers, ac- 

 cording to the time of the year in which the principal ascent of 'clean salmon' took place, 

 and this was associated with time of spawning whether in October, November, De- 

 cember, January, or February. As has been before remarked there are rivers in which 

 salmon appeared to run almost every month in the year, conditions being favorable. 

 Again some rivers appear to have two ascents, one in the spring, the other in the late 



