Quinn et al Origin and genetic structure of Oncorhynchus tshawytscha 



507 



Washington Dep. Fisheries 3 ; Oregon: Lichatowich, 

 1989; Nickelson et al. 4 ; Kaczynski and Palmisano 5 ; 

 California: Brown et al., 1994). The listing of certain 

 populations of chinook, Oncorhynchus tshawytscha, 

 and sockeye, O. nerka, salmon under the U.S. En- 

 dangered Species Act has further focused attention 

 on the concepts of population differentiation and lo- 

 cal adaptation (Waples, 1995). 



Despite the importance of the "stock concept" in 

 salmon management and the abundant examples of 

 variation among populations, there is little direct 

 information on genetic differentiation through the 

 processes of selection and drift. Transplants, however, 

 provide an opportunity to study these processes. Salmo- 

 nid transplants, undertaken since at least the middle 

 of the last century, have met with mixed success. Fresh- 

 water populations have been very widely established 

 outside the native range of such species as brook trout, 

 Salvelinus fontinalis (MacCrimmon and Campbell, 

 1969) and rainbow trout, O. mykiss (MacCrimmon, 

 1971), but anadromous populations 

 have proven difficult to establish in- 

 side or outside the species' endemic 

 range (Withler, 1982; Fedorenko and 

 Shepherd, 1986; Harache, 1992). For 

 example, anadromous sockeye salmon, 

 rainbow trout (steelhead), and Atlan- 

 tic salmon (Salmo salar) have estab- 

 lished only freshwater populations in 

 New Zealand (McDowall, 1990), and 

 the pink salmon ( O. gorbuscha ) trans- 

 plant to Newfoundland was unsuccess- 

 ful (Lear, 1980). The most long-stand- 

 ing, successful establishment of an 

 anadromous salmonid outside its na- 

 tive range has been the transplant of 



chinook salmon to New Zealand (NZ) (Fedorenko and 

 Shepherd, 1986; Harache, 1992). 



Between 1900 and 1906, chinook salmon embryos, 

 probably originating from Battle Creek, a tributary 

 of the Sacramento River (Fig. 1), were shipped to a 

 hatchery on the Hakataramea River, a tributary of 

 the Waitaki River (Fig. 2) on the South Island of NZ 

 (McDowall, 1994). Within about 10 years, chinook 

 salmon had established self-sustaining runs in other 

 major rivers on the east coast of the South Island up 

 to 230 km away (McDowall, 1990). No subsequent 

 introductions were made, thus NZ chinook salmon 

 developed from a discrete parent stock, relatively free 

 from hatchery influence. The Battle Creek popula- 

 tion has been maintained at the Coleman Hatchery 

 (Cope and Slater, 1957); thus we had the opportu- 

 nity to compare the genotypes of this and other Sac- 

 ramento River populations with the NZ chinook 

 salmon. In addition, chinook salmon from NZ rivers 

 differ from each other in important, heritable life 



2 Palmisano, J. F.. R. H. Ellis, and V. W. 

 Kaczynski. 1993. The impact of environ- 

 mental and management factors on Wash- 

 ington's wild anadromous salmon and 

 trout. Washington Forest Protection Asso- 

 ciation and Washington Department of 

 Natural Resources. 



3 Washington Department of Fisheries, Wash- 

 ington Department of Wildlife and Western 

 Washington Treaty Indian Tribes. 1993. 

 1992 Washington State Salmon and Steel- 

 head Stock Inventory, Olympia, WA, 211 p. 



4 Nickelson, T. E., J. W. Nicholas, A. M. 

 McGie, R. B. Lindsay. D. L. Bottom, R J. 

 Kaiser, and S. E. Jacobs. 1992. Status of 

 anadromous salmonids in Oregon coastal 

 basins. Oregon Dep. Fish and Wildlife, 

 83 p. 



5 Kaczynski, V. W., and J. F. Palmisano. 

 1993. Oregon's wild salmon and steelhead 

 trout: a review of the impact of management 

 and environmental factors. Oregon Forest 

 Industries Council, 328 p. 



39 N- 



Figure 1 



Map of the Sacramento River drainage showing the locations of populations of chinook 

 salmon, Oncorhynchus tshawytscha, used in the genetic comparison with New 

 Zealand populations. 



