The restocking of the waters will only be an efficient remedy in places where the fry will not be subject to the disadvantages we have suggested and others of equal importance. It is well known that man}% if not all, of the fish that frequent the Hudson, or any large river, run into the smaller streams to spawn. The practical closing of many such streams by means of dams, where no fish-ways are provided, must of necessity militate greath' against the natural increase.

442 The Hudson River

Under favourable conditions this increase would be enormous. A single female tomcod, for instance, will produce fifty thousand eggs or more. Two hundred and eighty-eight thousand such eggs would just fill a quart measure. But in order to secure the development of even a small percentage of all this embryonic life it is necessary to have undisturbed, fairly pure, and abundant water. At the hatcheries of the State Commission it has been found that the shad fry, if they are to be raised at all, must never be handled even with the nets that may be used in the rearing of young trout or salmon. The ideal pond for hatching purposes is one that has been dry for months, so that all life in it is destroyed, and then filled by seepage, thus excluding enemies that would otherwise destroy the adolescent shadlings. It will be readily seen that the natural conditions of the Hudson and its tributaries at the present day are not conducive to the increase of delicate fish.