INTRODUCTORY REMARKS. 45 



By what means nations may effectively convert un- 

 productive rivers into the means for supplying the 

 largest quantity of valuable food to their public ? 



As a river fish, we may consider salmon by far the 

 most valuable and the most important to cultivate. 



We will suppose the salmon to reside half its life in 

 salt water, and half in fresh ; it is obvious that we 

 know but little of its sojourn in the sea, except that it 

 becomes fat and flourishing after going down in a 

 very exhausted and impoverished condition, unfit for 

 human food, distressed and tormented by parasites 

 which attach themselves to its body, and of which it 

 quickly rids itself in the salt water, where it no doubt 

 finds abundance of food in the offspring of other fish ;* 

 in fact, we may conceive vast basins in the bed of the 

 sea overflowing with Crustacea and the fry of coarse 

 fish, a salmon-food as rich and palatable to the hungry 

 salmon as the finest basins of turtle soup would be to 

 a hungry man. And with this food it may gorge it- 

 self, and increase from the size of two ounces to five, 

 six, or eight pounds in a few months ; in fact, its 

 growth has been occasionally found after it has been 

 in the sea a few months,f to be sixty times its pre- 

 vious weight, whereas in the rivers its chief food con- 

 sists of insects and their larvse, as well as loach and 

 small eels. 



After having renovated itself, it becomes the prey 

 of other enemies, but ultimately, in obedience to the 

 promptings of its migratory iustinct, it returns back 

 to the fresh water, and again to the river where it 

 reproduces its species. 



* The late Professor Quekett believed the food of the salmon to 

 be the ova of the Echinus or Sea Urchin, as he always found this ia 

 their stomachs. Herrings are also occasionally found in their 

 stomachs. 



f It has been proved that some smolts remain in the sea one year 

 and upwards, and that some do not remain in the sea longer than a 

 few months, 

 it 2 



