88 THE HISTORY AND HABITS OF THE SALMON. 



salmon never spawn in sea-water, but they never spawn 

 in deep, whether salt, brackish, lake, or river water ; they 

 spawn invariably in shallow running water, in those parts 

 of rivers of such depth, current, and exposure as will 

 admit of a certain degree of oxygenisation from sun or 

 atmosphere, without which salmon ova will not be vivified. 

 Impregnated salmon ova have been repeatedly placed in 

 the sand and gravel of the depths of rivers, and have been 

 in every instance non-productive; portions of the same 

 impregnated ova have been embedded in the running 

 shallows of the same river, and have been invariably pro- 

 ductive more or less according to season casualties favour- 

 able or unfavourable. What I have stated is the result 

 of the observations and experiments of many persons ; 

 much of what I am about to say has been seen by thou- 

 sands, and all is proven by observation, experiment, and 

 the most direct and conclusive inductive reasoning and 

 inference. The male and female salmon appear together 

 on that part of a shallow in which their bed is to be dug, 

 and they /.remain moving about upon it for a few days 

 before they begin the process of nidification ; no precise 

 period can be fixed for such appearance. Salmon spawn- 

 ing beds are made by the fish in some sandy or gravelly 

 part of the river, generally high up towards its source, and 

 not unfrequently in rivers, and almost rivulets, tributaries 

 to some larger river, itself tributary to the sea. Before 

 two salmon, male and female, commence the formation of 

 their nests, they make efforts to drive away every fish 

 within their immediate vicinity. The spawning season 

 extends over a period of six continuous months ; on an 

 average it begins about the middle of September, and ends 

 about the middle of the following March. I may here 

 remark that very few fish spawn so early as in September, 

 and still fewer so late as in March. If the spawning 

 season lasts, more or less, for six months, we must have 

 salmon fry of various sizes and smolts in the river all the 

 year round. The reader will find the following correct : 

 The first fish that appear on the spawning beds are grilses, 

 or young salmon of the previous year's incubation, and 

 they are generally the precursors of mature salmon, that is, 

 of fish in their third year and upwards. From the middle 



