FISHERY BULLETIN: VOL. 71, NO. 3 



Table 7. — Estimates of mortality (monthly), maturity, 

 survival, and abundance parameters for 1965-66 brood 

 coho salmon from Columbia River hatcheries — river 

 sections combined. 



Parameter 



Estimated volue 



1965 brood 



1 966 brood 



m 



Ml 



Ml 



F 



M 



NiJNo 



SI 



S2 



0.0373 

 .4029 

 .0644 

 .3320 

 .6969 

 .0858 

 .0530 

 .0891 

 ,1037 



0.0321 

 .3862 

 .0613 

 .3000 

 .6670 

 .0954 

 .0602 

 .0985 

 .1243 



1965 brood (4% compared with 3% ). In general, 

 estimates of all parameters are very similar for 

 both broods. It should be remembered that 

 despite the similarity between broods for all 

 river sections combined, there was considerable 

 variation between sections (Tables 4, 5). 



DISTRIBUTION 



Distribution by Area 



Figure 4 depicts the calculated recoveries of 

 the different groups of marked coho salmon in 

 the different fisheries for both the 1965-66 

 broods. Because any fish which had a regen- 

 erated maxillary mark, or for which the maxil- 

 lary mark was not observed, would be listed 

 with the adipose only marked fish, in all prob- 

 ability this Ad-only group of recoveries actually 

 includes many fish from the other groups of 

 marks. This also is suggested by the large num- 

 ber of recoveries of Ad-only marks compared 

 with the other groups (see footnote 2). 



Despite these difficulties, however, it is pos- 

 sible to compare directly the Ad-LM (Upper 

 River) and Ad-RM (Lower River) recoveries. 

 There appears to be a tendency for a greater 

 percentage of the Lower River marks (Ad-RM) 

 to be recovered in the California troll fishery, 

 indicating a greater tendency to migrate south 

 from the Columbia River; this was particularly 

 evident for the 1965 brood fish. Also, there 

 appears to be a tendency for a greater percent- 

 age of the Lower River fish to be caught in the 

 Oregon ocean fisheries compared with the 

 Washington ocean fisheries, whereas the reverse 



British ColunibiaN 

 Washington 

 Columbio Rivei 

 Oregon 

 California 



N= 11,276 



British Columbia 

 Washington 

 Columbia River 

 Oregon 

 California 



N- 69026 



Ni: 62.468 



British Columbia 

 Washington 

 Columbio River 

 Oregon 

 California 



8 N=8.779 



I „; 



» o 



> — 



British Columbia S 



Woshington f:;::;:: 



N=ie53 



Figure 4. — Calculated recoveries (in percent) in various 

 fishing areas of marked 3-yr-old coho salmon from Colum- 

 bia River hatcheries. 



was true for the Upper River (Ad-LM) marks. 

 Again this would be consistent with the possi- 

 bility that a greater portion of the Lower River 

 fish (Ad-RM) tend to migrate south from the 

 Columbia River compared with the Upper River 

 fish (Ad-LM). As might be expected from the 

 greater exposure to river fishing, a greater per- 

 centage of Upper River fish were recovered in 

 the Columbia River fisheries. 



The marks from above The Dalles '(D-Ad) 

 were not consistent in this respect, although 

 they did show a greater percentage recovery in 

 California fisheries than in British Columbia 

 fisheries. This possibly indicates a greater por- 

 tion of these fish also migrated south from the 

 Columbia River. 



Finally, when the recoveries from all hatch- 

 eries are combined, the data indicate that the 

 percentage of these fish caught in the British 

 Columbia and California ocean fisheries is about 

 equal (less than 10%), whereas the percentage 

 recovered in the Oregon ocean fisheries is some- 

 what greater (from less than 1 to over 12% ) 

 than that recovered in the Washington fisheries. 



688 



