LANDER and HENRY: 1965-66 BROOD COHO SALMON 



recoveries in the Oregon and California ocean 

 fisheries for the 1965 brood but was not evident 

 for the 1966 brood data. We also can look at 

 recoveries in the Zone 1 (lowest) fishery in the 

 Columbia River (Table 10). For both brood 

 years the Upper River marks (Ad-LM) peaked 

 earlier and disappeared first from the catches 

 when compared with the Lower River marks 

 (Ad-RM). Of course, in view of the longer migra- 

 tion up the Columbia River for the Upper River 

 fish, this phenomenon might be expected. 



Table 10. — Calculated recoveries (in percent) by time of 

 marked Upper River and Lower River coho salmon in the 

 Columbia River Zone 1' fisherv. 



* Zone 1 extends from the mouth of the Columbia River to 

 the Elokomin River (see Figure 1). 



LITERATURE CITED 



Cleaver, F. C. 



1969. Effects of ocean fishing on 1961-brood fall 

 Chinook salmon from Columbia River hatcheries. 

 Fish Comm. Oreg., Res. Rep. 1( 1 ). 76 p. 

 Fredin, R. a. 



1964. Ocean mortality and maturity schedules of 

 Karluk River sockeye salmon and some compari- 

 sons of marine growth and mortality rates. U.S. 

 Fish. Wildl. Serv., Fish. Bull. 63:55 1-574. 

 Henry, K. A. 



1971. Estimates of maturation and ocean mortality 

 for Columbia River hatchery fall chinook salmon 

 and the effect of no ocean fishing on yield. Fish. 

 Comm. Oreg., Res. Rep. 3: 13-27. 

 Lander, R. H. 



1973. Problem of bias in models to approximate 



ocean mortality, maturity, and abundance schedules 



of salmon from known smolts and returns. Fish. 



Bull.. U.S. 71:513-525. 



Merrell, T. R., Jr., M. D. Collins, and J. W. 



Greenough. 



1971. An estimate of mortality of chinook salmon in 

 the Columbia River near Bonneville Dam during 

 the summer run of 1955. U.S. Fish Wildl. Serv., 

 Fish. Bull. 68:461-492. 

 Parker, R. R. 



1962. Estimations of ocean mortality rates for 

 Pacifiic salmon (Oncorhynchus). J. Fish. Res. 

 Board Can. 19:561-589. 



1968. Marine mortality schedules of pink salmon of 

 the Bella Coola River, central British Columbia. 

 J. Fish. Res. Board Can. 25:757-794. 



PaULIK, G. J., AND D. S. ROBSON. 



1969. Statistical calculations for change-in-ratio 

 estimators of population parameters. J. Wildl. 

 Manage. 33:1-27. 



RiCKER, W. E. 



1962. Comparison of ocean growth and mortality of 

 sockeye salmon during their last two years. J. Fish. 

 Res. Board Can. 19:531-560. 



691 



