pens are included. Females entering the traps 

 will not be more than 3 or 4 days from ripeness 

 unless the pond is still receiving fish while trap- 

 ping is in progress . Under the latter conditions 

 immature fish may enter the traps. Females 

 more than 3 or 4 days from maturity should be 

 returned to the pond, those approaching ripe- 

 ness are held separately from those fully mature. 

 The holding pens are used to segregate the green 

 and ripe females and retain the males . The ripe 

 pens are essential in order that the fully mature 

 females may be held an additional day before 

 taking the eggs . All pens and traps are equipped 

 with brails or false bottoms to facilitate the man- 

 ual sorting of the fish . 



The upstream trapping system : --The in- 

 troduction of water into the upstream holding pens 

 and trap, as shown in figure 3, employs the dif- 

 fusion principal. The sidewalls with the excep- 

 tion of the picketed entrance "V" are solid and 

 the water directed by means of conduits and 

 baffles . The water upwells through the brail in 

 the upstream half of the ripe pen, is withdrawn 

 through the brail in the downstream half of the 

 pen, divided and diverted into the two side pens 

 in the same manner, upwells through the up- 

 stream half of the trap and flows through the 

 picketed "V" into the pond. The upstream trap- 

 ping system is designed to operate on approx- 

 imately 15 cfs of water with the remaining 20 cfs 

 diverted by conduit to the sloping diffusion panel 

 at the trap entrance to provide attraction water 

 when the trap is in operation . 



The downstream trapping system: - - The 

 water pattern in the downstream traps, as shown 

 in figure 4, is practically the reverse of that em- 

 ployed in the upstream trapping system . In the 

 trap itself only the sidewalls and bottom are 

 solid with the water entering through the vertical 

 picket sections of the trap face and "V" and pass- 

 ing through a second vertical picket section at 

 the downstream end of the trap into the holding 

 pens . In the holding pens the water is withdrawn 

 through a bottom conduit discharging into the 

 fish ladder . The depth of water in the pond and 

 the flow through the downstream traps is con- 

 trolled by the height of the upper set of stoplogs 

 in the ladder and the conduit gates which dis- 

 charge below these logs . Flow through the traps 

 is regulated to approximately 10 cfs each, during 

 trapping operations . 



The angle to the current of the main "V" 

 is continued in those of the two downstream traps . 

 The trap entrances must be restricted by means 

 of the swinging tunnel, shown in figure 4, other- 

 wise large numbers of trapped fish will find the 

 entrance and escape. The use of the tunnel-type 

 entrance, however, has proved very effective 

 in the retention of the trapped fish . When built 

 to the specifications shown, the tunnel will re- 

 tain fish from 2 pounds to 60 pounds in weight 

 without impeding the ingress of the larger fish. 



All traps and pens are equipped with re- 

 movable, framed, folding, canvas covers. The 

 darkness and protection provided by the covers 

 cause the fish to rest more quietly in both the 

 traps and pens . While the diffusion method of 

 water introduction is designed to reduce jumping 

 at the inflow, some fish may jump at the straight 

 sidewalls of the traps and pens . Should jumping 

 occur it may be necessary to float wide, canvas 

 strips on the water surface. Salmon recognize 

 an obstruction located at the water surface. The 

 fish will attempt to jump through a similar barrier 

 located even two or three inches above the water 

 surface. 



Operation of the trapping facilities 



Approaching ripeness in the female is in- 

 dicated by a constriction of the generally distended 

 abdomen in the area directly anterior to the vent, 

 a general restlessness as indicated by cruising 

 in the shallow areas of the pond, and interest by 

 the males. When these symptoms are first shown 

 by a few fish it is time to activate the traps by 

 opening the "V"s and rerouting the water through 

 the trapping system . 



Routine procedures: - -Once spawning op- 

 erations are underway the daily routine in the 

 upstream trapping system is as follows: 



1 . The brail in the ripe pen is raised and the 

 males and females spawned. This procedure 

 empties the ripe pen. 



2 . The brail in the green pen is raised, a 

 movable separator introduced, the fish sorted, 

 and the ripe females transferred to the ripe pen. 



3 . The brail of the trap is raised and the fish 

 sorted, ripe females into the ripe pen, green 



11 



