AKTIFICIAL, PROPAGATION OF WHITEFISH, ETC. 25 



with water at least once every 24 hours. If held for a longer period 

 than four or five days, they must be taken from the trays and washed 

 in a tub of water in the manner described in taking spawn. In add- 

 ing water the dipper is either held down near the eggs or the water 

 is poured against the side of the tub a little above the surface of the 

 spawn in order to guard against its striking them with such force as 

 to cause injury. Poured in this manner the eggs are given a steady 

 whirling motion and are not injured. 



The pi'ocess of transferring eggs from trays to a tub is very simple. 

 After filling a tub with water to about one-third of its capacity a 

 tray of eggs is placed in the water at an angle of about 45° with its 

 surface, causing most of the eggs to slide down the incline into the 

 tub. The few remaining eggs may be washed down by pouring a 

 little water on the uppermost side of the tray. After giving the 

 eggs a good washing they are replaced on the trays and returned to 

 the cases as described above. 



The eggs are shipped in charge of a messenger to insure careful 

 handling at transfer points and when being placed in the baggage 

 car. They must be kept in the coolest place in the baggage car, pro- 

 vided its temperature is not below 28° or 30° F. 



MORTALITY OF LAKE-TROUT EGGS. 



Because of the difficulties encountered in collecting lake-trout eggs 

 from commercial fishermen for artificial propagation it is not sur- 

 prising that the percentage of fry produced from such eggs falls 

 below the percentage realized in the hatching of other species of 

 trout whose eggs are obtained under more promising conditions. 



In common with the eggs of all the trouts and salmons, the eggs 

 of the lake trout display a strong adhesive tendency when first ex- 

 pressed from the fish. This characteristic persists for a longer or 

 shorter period, apparently depending to a considerable extent on the 

 water temperature. The necessity of absolute quiet during this 

 period has long been recognized in fish-cultural practice. The roll- 

 ing and pitching of the boats upon which the spawn takers operate 

 prevent the eggs from separating naturally. Separation should 

 occur approximately within 30 minutes after the eggs are stripped, 

 but, as the boats are out from 5 to 24 hours or longer, quiet is no 

 longer of value when they reach the shore. Furthermore, the tem- 

 perature often falls below the freezing point, and despite all pre- 

 cautions considerable numbers of the eggs are frequently chilled, 

 though the ill effects may not become apparent until after they have 

 reached the hatchery. Other losses often occur through accident or 

 the carelessness of those handling the cases of green eggs while en 

 route to the hatchery. 



It is ver}^ probable that the greatest loss occurs through improper 

 taking of the eggs. The bureau can not place experienced spawn 

 takers on all the boats, and the fishermen of the smaller outfits 

 take the eggs available and are sometimes careless in performing 

 the operation. Frequently eggs and milt are taken from fish that 

 have been dead for some time. After taking the eggs they are not 

 always cleaned and carefully placed in the kegs. The fishermen are 

 naturally more interested in the catch of fish than in the care of 

 the eggs. 



