SPAWNING HABITS OF THE SALMON. 471 



and July, though some come as early as April, and in the Miramichi from the middle of June to 

 October. I can only account for this seeming paradox by the theory that, while Salmon are not 

 harmed by extreme variation of temperature, they may be averse to sudden changes, and though 

 strongly impelled to seek the spawning grounds are prevented by the cold. I have ascertained 

 that the cod possess very little animal warmth. The temperature of the blood of a number <>f 

 individuals caught in twenty-live fathoms of water was 47 Fahrenheit, precisely that of the water 

 at the bottom whence they were lifted. Mackerel swimming at the surface registered 50 or GO , 

 while the. temperature of the water was 58, thus indicating that they possess a trifling amount of 

 animal heat. The Salmon unquestionably changes its temperature with that of the surrounding 

 water in much the same way, and if, as is probable, rivers rising in the mountains are colder in 

 early spring than the ocean strata frequented by the Salmon, here, is a possible solution of the 

 problem. It is stated that in the English rivers, which are always open, there are no regular 

 seasons of ascent, the fish constantly passing in and out; indeed, Mr. Atkins thinks it pretty 

 certain that large Salmon in prime condition are running into the Peuobscot from the sea every 

 mouth in the year. It is likely, also, that the warmth of the rivers is an important factor in accel- 

 erating the vegetative growth of the eggs in the ovaries of the mother fish. 



The movements of the Salmon are not so intimately related to the temperature of the water 

 as those of many other species. They are not sensitive to sudden changes, and are capable of 

 enduring a range of at least forty-five degrees. In this they resemble less the migratory fishes 

 than the permanent residents of our fresh waters; indeed, it is quite allowable to speak of them 

 as resident, for a large proportion of the whole colony belonging in one river may be found in it at 

 any season. This proportion cannot fall much below two-thirds, if we consider that the iish less 

 than a year old would make up at least half its number, and that the breeding fish are in the 

 rivers six or seven mouths after the breeding. The breeding Iish remain during the se.ison of 

 greatest heat and greatest cold, though their stay after they have deposited their eggs is no 

 doubt chiefly because their vitality is diminished and their circulation retarded by the falling tem- 

 perature, depriving them alike of the craving for food and the power to seek it. Those which 

 spawn early are believed to return at once to the sea; the. more tardy ones often remain all 

 winter, and are carried out by the spring freshets. Salmon eggs are not injured by freezing, and 

 the fish are unquestionably quite as hardy. English fish-cultnrists claim that their Salmon will not 

 thrive where the water is wanner than G0, or at most (J5 in the summer, but Mr. Atkins kept fish 

 in his ponds at Bucksport, Maine, with the water at the bottom as warm as 74^ at midday. I lie 

 means of bottom and surface temperature for June, July, August, September, and October, 1872, 

 being GO.C, G5.9, G9.S, 59, 50.:j, and 7i'.9, 73.l, 73.G, G2.2, 54.3, respectively. In the Gasp6 

 salmon streams, where the fish are in the perfection of activity, the temperature of the pools in 

 July ranges from 40J to 59. 



KELTS. At the approach of the spawning season their dim shapes and bright colors disappear. 

 They grow lank and misshapen, the fins grow thick and fleshy, and the skin, which becomes thick 

 and slimy, is blotched and mottled with brown, green or blue, and vermilion or scarlet. These 

 changes are chiefly apparent in the males, whose jaws now become curved so that they touch only 

 at the tips, the lower one developing a large, powerful hook, which is his weapon in the savage 

 combats with his rivals in which he at this period engages. When in this condition, and after 

 spawning, when they retrace their course to the sea, they are known as "Kelts." 



Having entered a river, they press on to its headwaters, where the earliest of them arrive two 

 or three months before spawning time. As soon as the water is cool enough they proceed to deposit 

 their eggs, in deep furrows which they plow up in the sandy or gravelly bottom of the stream, 



