134 How to obtain it. 



outlet spouts when it is desired to increase the depth of the water, 

 and pieces of either wood or slate will be found very useful for 

 the purpose. Both inside the hatchery and outside in the 

 raceways, they are often very useful indeed. A trap box should 

 be placed below the spout of the last hatching box in each set. 

 It does not matter how small it is, but one side should be of 

 perforated zinc, to within say an inch of the bottom. Through 

 this box the water should pass before it is allowed to flow into the 

 gutter that carries it off. The object of these trap boxes is to 

 catch any fish that may be escaping, and they play a much more 

 important part in the working of a hatchery than many persons 

 would suppose. 



I have more than once been told by one of my friends that 

 his fry were decreasing in numbers, and he could not tell what 

 was taking them. On my suggesting that they might be escaping, 

 the idea would not be entertained for a moment. Impossible ! 

 When my friend, acting on my suggestion, had placed a trap box 

 below his outlet spout, he soon found out where the fish were 

 going. A few hours would reveal the fact that a dozen or more 

 had escaped from the box above during that short time. On a 

 search being made for the crevice through which they had 

 escaped, it would be very difficult to find it, and when found my 

 friend would hardly be convinced that the little fish could possibly 

 have escaped through such a small aperture. Even in a well- 

 ordered hatchery there is always a liability that some such 

 occurrence may take place, and it is better, therefore, to be 

 prepared for it. With these traps in use such a leakage would be 

 detected at once. 



There is another very important accessory to the hatchery 

 also, and that is a catch pool. It consists of a pool or pond 

 outside the hatchery, in any convenient situation. It may be near 

 or at a little distance, but it is at least better to have it a few 

 yards away, so as to get the advantage of having a raceway leading 

 to it. It may be made of any convenient shape, but for practical 

 purposes a long and narrow pond suits best. Some fish will be 

 picked out of the hatchery boxes occasionally, apparently nearly 

 dead. They are at least in such a plight that any fish culturist 

 would condemn them. Do not throw such away, but as long as 



