1050 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. [14] 



The ponds are planked aU around, the planks being spiked to stakes 

 driven in front. Between and around all the ponds, and of the same 

 height as the planking, is a jiier of earth 8 feet wide, and across this 

 are laid pieces of 2 by 4 firmly spiked to the stakes to which the planks 

 are nailed. Being thus secured it is quite impossible for the earth to 

 cave in or the sides of the pond to bend in or out. The bottom plank 

 is set in a bed of gravel and blue clay, and a heavy body of the same 

 material, well champed in, backs the planking up to the top of the pier, 

 so that the ponds are practically water-tight, while the efforts of musk- 

 rats to invade them by burrowing underneath will be futile. Each pond 

 is usually filled to within a foot of the top, the bottom sloping gradually 

 from the head, where the water is 18 inches in depth, to the foot, where 

 it is 4 to 5 feet. The overflow gates of the discharging flumes are easily 

 raised by a lever attachment at the bottom, so that the water can be 

 drawn off in a few moments. The gates are made in sections, one or 

 more of which can be removed to give any desired depth of water. 



As quite a number of fish will spawn in the ponds instead of running 

 up the raceways, if the former have gravel bottoms, which they should 

 have, those in which the breeders are placed during the spawning season 

 are divided into two sections by a temporary partition, and the bottom 

 of the upper section covered with boards. The fish all being placed in 

 this, but few, if any, eggs will be lost, and as fast as the fish are handled 

 from the raceways they are transferred to the lower section. At the 

 close of the spawning season the partition is removed. 



At the mouth of the flume connecting the upper section with the race- 

 way a trap-gate, sprung with a string leading to the hatchery, is fitted, 

 a simple but very useful device, for no matter how stealthily one ap- 

 proaches, nor from what direction, some of the fish in the raceway will 

 detect the movement and dart back to the pond before the gate can be 

 dropped to head them off. 



The fish are given access to the racewaj's at all seasons of the year, 

 and hither they resort largely at other than spawning time. A raceway 

 fed directly from a copious spring of cold water, and given sufficient fall 

 to create a sparkling current over its clean, gravelly bottom, affords an 

 attractive "summer resort" to trout having admission to it, and here, 

 in warm weather, many of them congregate, lying nearly motionless, 

 with head up stream, for hours together. At the approach of cold 

 weather, when an equally satisfactory temperature is found in the ponds, 

 this practice is discontinued, except mth the ripening females, which, 

 with a heavy body- guard of males, and in response to that instinct which 

 impels them to deposit their eggs in a current, begin to prepare spawn- 

 ing beds in the raceway, whence they are easily captured at the proper 

 time for the purpose of expressing their eggs. 



The breeding fish are quartered in ponds nearest the feeding springs 

 for some time preceding the spawning season, and, when most couven- 

 This gives them the least variance of temperature 



