236 REPORT OF THE COMMISSIONERS OF 



provided in which to rear fry to yearlings, at least, before they are planted in waters 

 to be fished, if the best results are to be obtained from this system of hatching fish, 

 for the young fish must be of sufficient size to be reasonably sure that the greater 

 portion of them will escape the maws of their larger brethren in the water 

 they are to stock. 



The hatchery shown in the illustration is 400 feet long and eight feet wide, and a 

 cross section will be found in the upper right hand corner of the plate. At the base 

 of the ridge are a number of springs, which feed two of the ponds, and the hatchery is 

 constructed over them and consists only of a frame of joists, 2x5 and 2x7, top and 

 sides boarded over, with doors at intervals in the incline of the roof nearest to the 

 ponds. There is a division in the hatchery about midway of its length making 

 one-half of the hatchery a little higher than the other, made necessary by the 

 conformation of the shore. From the bottom of the hatchery to the slope of the roof 

 is about six feet, and two feet of this, or a little more, is beneath the level of the 

 ground. From the midway division, the water as it comes from the springs under- 

 neath is directed to flow in opposite directions by the grade at the bottom, and finds 

 its way through sluices with screened gates, into the fourth and fifth ponds. About 

 thirty feet of either end of the hatchery is divided from the balance by upright 

 planks forming a dam, which also holds the gravel in place, with an inch or two of 

 fall and the bottom covered with clean sand, and all that remains is covered with white 

 gravel, well screened, and in size from a pea to a pigeon's egg and ten inches 

 deep; over the gravel the water is six to eight inches in depth, flowing in a gentle 

 current toward the ends. Explicit directions are not given as to kind and sizes of 

 lumber used in the construction of this particular hatchery, as it is expected that 

 any one building a similar hatchery may have to be governed by different conditions 

 from those found on Long Island, but that portion of the structure which comes in 

 contact with the water should of choice be built of pine lumber and tarred with gas 

 tar, or so much of it as is under ground or is washed by the water. Untarred pine 

 may serve if the water is allowed to thoroughly soak the wood before any hatching is 

 done, but tarred wood underground or in the water is preserved for a longer time than 

 untarred, and it is safer for fry. An experiment with new helmlock planks in such a 

 hatchery killeu a large number of fry before they could be removed. 



The outlets of water at either end of the hatchery form natural spawning races 

 between it and the breeding ponds and in it the movements of the fish may be 

 governed by sliding, screened gates. In the autumn, when the trout, moved by the 

 spawning instinct, crowd into the races, the screens are lifted and they are allowed to 

 make their way into the hatchery and on to the prepared gravel beds. After the trout 

 , have spawned, they are driven out of the hatchery through the races back to the 



