312 Salmonide 
spawning grounds. In years of high water doubtless many 
salmon run in the spring which might otherwise have waited 
until fall. 
The key to the situation lies in the artificial propagation of 
salmon by means of well-ordered hatcheries. By this means the 
fisheries of the Sacramento have been fully restored, those of the 
Columbia approximately maintained, and a hopeful beginning 
has been made in hatching red salmon in Alaska. 
The preservation of salmon and trout depends rather on 
artificial hatching than on protection. 
Salmo, the Trout and Atlantic Salmon.— The genus Salmo 
comprises those forms of salmon which have been longest 
known. As in related genera, the mouth is large, and the 
jaws, palatines, and tongue are armed with strong teeth. The 
vomer is flat, its shaft not depressed below the level of the 
head or chevron (the anterior end). There are a few teeth on 
the chevron; and behind it, on the shaft, there is either a 
double series of teeth or an irregular single series. These teeth 
in the true salmon disappear with age, but in the others (the 
black-spotted trout) they are persistent. The scales are silvery 
and moderate or small in size. There are g to 11 developed 
tays in the anal fin. The caudal fin is truncate, or variously 
concave or forked. There are usually 40 to 70 pyloric cceca, 
11 or 12 branchiostegals, and about 20 (8+12) gill-rakers. 
The sexual peculiarities are in general less marked than in 
Oncorhynchus; they are also greater in the anadromous species 
than in those which inhabit .fresh waters. In general the 
male in the breeding season is redder, its jaws are prolonged, 
the front teeth enlarged, the lower jaw turned upwards at the 
end, and the upper jaw notched, or sometimes even perforated, 
by the tip of the lower. All the species of Salmo (like those of 
Oncorhynchus) are more or less spotted with black. Unlike 
the species of Oncorhynchus, the species of Salmo feed more or less 
while in fresh water, and the individuals for the most part 
do not die after spawning, although many old males do thus 
perish. 
The Atlantic Salmon.—The large species of Salmo, called 
salmon by English-speaking people (Salmo salar, Salmo trutta), 
are marine and anadromous, taking the place in the North 
Atlantic occupied in the North Pacific by the species of Onco- 
