(Berst and Spangler 1973; Christie 1973; Wells 

 and McLain 1973). As a result the State of Michi- 

 gan in 1966 undertook a program to establish coho 

 salmon, Oncorhynchus kisutch, in Lakes Michi- 

 gan and Superior in hopes of creating a valuable 

 sport fishery based on alewife as the major forage 

 species (Tody and TannerV). The success of the 

 Michigan program provided an incentive to other 

 states and provinces bordering the Great Lakes to 

 undertake similar programs. 



New York State began its salmonid program for 

 Lake Ontario in 1968 w^hen 41,000 coho salmon 

 were planted in the Salmon River. The following 

 year 70,000 chinook salmon, O. tshawytscha, were 

 planted in the Little Salmon River (Parsons 1973). 

 Stocking of steelhead, Salmo gairdneri, com- 

 menced in 1974 (Parker^). Stockings of coho salm- 

 on and steelhead have continued annually since 

 their inception. Chinook salmon plantings were 

 stopped after releases in the spring of 1976 be- 

 cause contaminant levels in their flesh generally 

 exceeded action levels for Mirex^ and PCB's when 

 these fish first became available to anglers as pre- 

 cocious jacks on their maiden spawning run at 

 1.8-2.7 kg (New York State Department of En- 

 vironmental Conservation^). However, chinook 

 salmon stocking was resumed in 1979. 



From its inception, Michigan's salmonid pro- 

 gram has given high priority to natural reproduc- 

 tion as a supplement to hatchery production (Tody 

 and Tanner footnote 1). Subsequent studies have 

 focused on the extent of natural reproduction in 

 Michigan (Stauffer^) and other ecological aspects 

 of spawning activity (Taube^). Reproductive suc- 

 cess of Pacific salmonids has been examined in 

 Minnesota (Hassinger et al. 1974) and Wisconsin 



•Tody, W.H., and H. A. Tanner. 1966. Coho salmon for the 

 Great Lakes. Mich. Cons. Dep. Fish. Manage. Rep. 1, 38 p. Fish 

 Division, Michigan Department of Natural Resources, Mason 

 Building, Lansing, MI 48926. 



^C. E. Parker, Chief, Bureau of Fisheries, New York State 

 Department of Environmental Conservation, 50 Wolf Road, Al- 

 bany, NY 12233, pars, commun. October 1979. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



"New York State Department of Environmental Conserva- 

 tion. 1977. Monthly report on toxic substances impacting on 

 fish and wildlife. Rep. 1, April 20, 1977. 



^Stauffer, T. M. 1977. Numbers of juvenile salmonids 

 produced in five Lake Superior tributaries and the effect of 

 juvenile coho salmon on their numbers and growth, 1967- 

 1974. Mich. Dep. Nat. Resour, Fish. Res. Rep. 1846, 29 p. Insti- 

 tute for Fisheries Research, Museums Annex Building, Ann 

 Arbor, MI 48109. 



^Taube, C. M. 1975. Abundance, growth, biomass, and in- 

 terrelationship of trout and coho salmon in the Platte 

 River. Mich. Dep. Nat. Resour., Fish. Res. Rep. 1830, 82 p. 

 Institute for Fisheries Research, Museums Annex Building, Ann 

 Arbor, MI 48109. 



(Avery''). Canadian studies on Great Lakes 

 tributaries have mainly focused on steelhead re- 

 production (Alexander and MacCrimmon 1974). 



In New York, chinook salmon begin their spawn- 

 ing run from Lake Ontario in late August and 

 early September ( Jolliff^). Chinook salmon redds 

 are present as early as mid-September in the 

 Salmon River in Oswego County. Although most 

 chinook salmon spawning occurs in the Salmon 

 River, smaller tributaries are also utilized. Spawn- 

 ing in smaller tributaries usually does not begin 

 until late September with the peak occurring in 

 mid-October. The selection of larger tributaries 

 such as the Salmon River for spawning is charac- 

 teristic of chinook salmon in their native range 

 (Stein et al. 1972; Scott and Grossman 1973). Coho 

 salmon run somewhat later than chinook salmon, 

 usually beginning in late September and peaking 

 in late October to early November. Limited coho 

 salmon spasming activity occurs in the Salmon 

 River, possibly because of the large size of the 

 substrate materials. Adult steelhead are present 

 in the Salmon River throughout the fall and into 

 early summer. Steelhead can be found in the 

 smaller tributaries from March through June 

 with most spawning activity occurring in April 

 and May. Stream residence time for juvenile salm- 

 onids in the Salmon River system is <1 yr for 

 chinook salmon, up to 1 yr for coho salmon, and up 

 to 2 yr for steelhead (Johnson 1978). 



Prior to 1977 the reproductive success of Pacific 

 salmonids was unknown in New York tributaries 

 of Lake Ontario. In 1977, five streams in the Salm- 

 on River system were examined for evidence of 

 successful spawning of coho salmon, chinook 

 salmon, and steelhead (Johnson 1978). Initial evi- 

 dence indicated substantial reproduction of coho 

 salmon and steelhead in some of the streams. The 

 purpose of this study was to quantify reproductive 

 success of Pacific salmonids in one tributary of the 

 Salmon River. 



Methods 



Orwell Brook was selected as it contained high 

 densities of coho and chinook salmon and 

 steelhead juveniles. Orwell Brook flows for ap- 



■^ Avery, E. L. 1974. Reproduction and recruitment of anad- 

 romous salmonids in Wisconsin tributaries of Lake 

 Michigan. Dingell-Johnson final Rep., Proj. F-33-R, Study 108, 

 Wis. Dep. Nat. Resour., 32 p. 



*T. Jolliff, Associate Aquatic Biologist, Bureau of Fisheries, 

 New York State Department of Environmental Conservation, 

 Cape Vincent, NY 13618, pers. commun. 



550 



