STATE OF WASHINGTON DEPARTMENT OF FISHERIES - EXHIBIT F 



2 Coho 



3 Several estimates of the expected 1967 coho 



4 catch have been derived from correlations with Puget Sound 



5 streamflow data. One method of estimating the total Puget 

 g Sound net catch Is based upon the total "cubic feet run 

 7 off per square mile of drainage area" (cfsm) for V^ashington 

 g streams during the calendar year when young coho are rearing 

 g in fresh water. This is the method we have been using for 



jQ the past several years to obtain our estimates, but several 



11 

 12 

 13 

 14 

 15 



17 



18 



drawbacks to this method have become apparent. First, a 

 high winter or spring flow can mask seriously low summer 

 flows; second, no consideration is given to increasing 

 hatchery production; third, the amount of fishing time 

 allowed varies greatly and the extremes in catches are 



jg exaggerated, 



A second method is presently under study 

 which utilizes the "cfsm" for the months of June through 



19 September, when summer flows are at the lowest levels. 



20 Preliminary results on this method show promise and 



21 indicate the possibility of a poor coho catch in Puget 



22 Sound this year of around 300,000 fish. The first method, 



23 on the other hand, indicates a catch of 37^^000. It is 



24 expected that the actual catch will lie somewhere between 



25 these two figures or about 350,000 , a catch which would be 



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 I 



