736 BULLETIN OF THE BUREAU OF FISHERIES. 



into the solution, the unfertilized and dead eggs rise to the surface, where they 

 may be quickly skimmed off. The method is not applicable in the manipulation 

 of small quantities of eggs, but is very useful when, for some cause, there is an 

 abnormal loss. It has not been successfully extended to the eggs of species 

 other than the chinook, silver, and humpback salmons. 



At the Baker Lake station, operated primarily for the propagation of the 

 sockeye salmon, both sockeye and silver salmon are captured by means of a 

 pound net as they enter the lake, but as the fish are not ripe at this stage of 

 their upstream passage it is necessary to hold them until the spawning season. 

 For this purpose a slough or bay at the head of the lake has been inclosed by 

 racks and webbing to make a pound about 20 feet wide and 500 feet long, with 

 an average depth of 6 feet. The entire bottom area is of soft mud; in it are two 

 hollows of a maximum surface area of 300 feet and 400 feet, respectively, where 

 the water is approximately 12 feet in depth. The water supply, from 800 to 

 2,400 gallons per minute, is derived from several small mountain creeks fed by 

 glaciers and snow, and from springs. 



This has proved an ideal place in which to hold salmon while their eggs are 

 maturing. As many as 8,000 fish have thus been confined for thirty days and 

 6,000 for three months. After remaining in the inclosure for three or four 

 months the fish are as clean and free from abrasion as fish that have not been 

 penned. A noticeable fact, however, is that very few of these salmon ripen 

 until October or November, while in previous years the spawning season has oc- 

 curred during September and before October 15. The difference is attributed 

 to the low temperature of the water in the inclosure, which remains from 6 to 8 

 degrees below that of the natural spawning beds of the lake. (During the sum- 

 mer the average water temperature on the spawning beds is about 56°.) The 

 success of the impounding of the salmon is attributed to the low temperature 

 of the water. 



Silver salmon, as well as socke3^e, have been successfully impounded at 

 Baker Lake. A few impounded chinook, however — never more than 12 at a 

 time — fungussed rapidly, and after three weeks usually died before the eggs 



were taken. 



MARINE FISH CULTURE. 



COD, POLLOCK, AND FLATFISH. 



On the New England coast the Bureau maintains three stations, for the 

 hatching of marine fishes and the lobster. 



Of the fishes the cod is first in importance. Its cultivation consists prin- 

 cipally in hatching eggs obtained from market fish, the fish being stripped either 

 by the fishermen or by the Bureau's spawntakers. The latter are daily distrib- 

 uted among the fishing vessels for the double purpose of stripping ripe fish as 

 fast as hauled aboard and of collecting and caring for all eggs the fishermen may 



