176 TRANSACTIONS iSgg-'oo 



of an inch in the tomcod {Gadus tomcod, Walb) or 1/25 of an inch 

 in the silver hake {Merlucius) .' 



When the ripe female fish is being spawned by the hatchery- 

 operator, the eggs run freely in a stream into the pan or dish, 

 previously rinsed in clean water, the operator gently pressing the 

 abdomen with one hand, while with the other he holds the fish 

 firmly in the region of the anal fin, the head of the fish being 

 secured under the armpit, if a large fish like a salmon. A male 

 fish is then treated in the same way, the milt flowing into the 

 spawning pan amongst the eggs, and the eggs are stirred with a 

 feather, thus securing fertilization. After being washed, the 

 eggs are placed either upon black Japanned tin trays, 15 in. x 

 10 in. X ^^in, perforated with small holes and holding about 

 2000 salmon eggs, or they are placed in glass vases 20 in. x 6 in. 

 in diameter. The former are more suitable for salmon and trout, 

 the jars being best for whitefish. Zinc trays are found hurtful 

 to eggs, the officer at the Miramichi hatchery reporting in 1874 

 that a large number of salmon eggs were poisoned from this 

 cause. The eggs, being alive, require abundant oxygen, hence 

 a continuous stream of water must pass over them day and 

 night until they hatch out. Under natural conditions river- 

 water, of course, pours over the eggs, but fish culturists are 

 agreed that spring-water is preferable for hatching purposes, not 

 only because the temperature is more equable, but is purer and 

 more free from debris and vegetable matter. In 90 to 120 or 

 150 days, the young fish burst from the eggs; shad, however, 

 take only from two to five days, and cod hatch in ten to thirty 

 days. Most of the valuable fresh-water species, like the trout 

 and whitefish take many months. In special cases where the 

 hatching of sturgeon and shad has been attempted as in 

 Chautauqua I^ake, N. Y., hatching boxes with double wire 

 screen, top and bottom, have been placed in a running stream, or 

 if containing maskinonge eggs, have been sunk at a depth of 

 four or five feet in the lake. The fry are transferred to large 

 tanks for periods of a few days or a few weeks, and are dis- 

 tributed in large cylindrical cans, nearly two feet high and 

 twenty inches in diameter, the narrow neck of which is devised 

 to hold ice in hot weather, in order to keep the water cool.* 



*Fry are conveyed up some salmon rivers in floating- crates or perforated 

 boxes, and 25 miles of a river can be planted in a day. 



