Evidence of partial anadromy and resident-form dispersal bias on a fine scale in populations of Oncorhynchus mykiss
- 213 Downloads
We examine sympatric anadromous (steelhead) and nonanadromous (resident) rainbow trout (Oncorhynchus mykiss) from neighboring locations to test three hypotheses: (1) the sympatric life history types are not genetically different; (2) fine-scale dispersal is the same for both sexes, and (3) fine-scale dispersal is the same for steelhead and resident individuals. Data from 13 microsatellite loci reveal no genetic difference between sympatric steelhead and resident O. mykiss but moderate population structure (F ST=0.019–0.028) between adjacent samples, regardless of life history type. Our results provide further evidence of partial anadromy and suggest that geographic proximity and genetic history, more than migratory type, should be considered when identifying populations for use in restoration of local genetic diversity. We find evidence of resident-form dispersal bias on a fine spatial scale, however, we find no evidence that fine-scale dispersal varies by gender. Conservation strategies should aim to maintain resident and anadromous forms when they occur in sympatry, as they may be important in facilitating gene flow on small and large spatial scales, respectively.
Key wordsdispersal bias Oncorhynchus mykiss partial anadromy
Unable to display preview. Download preview PDF.
Substantial assistance in acquiring population samples was provided by Elijah Waters (US Bureau of Land Management). Partial funding was provided by the USFWS Office of Subsistence Management. The findings and conclusions given here are those of the authors and do not necessarily represent the views of the US Fish and Wildlife Service.
- Busby PJ, Wainwright TC, Bryant GL, Lierheimer L, Waples RS, Waknitz FW, Lagomarsino IV (1996) Status Review of West Coast Steelhead from Washington, Idaho, Oregon and California. US Dep. Commer. NOAA Tech. Memo, NMFS-NWFSC-27, 261pGoogle Scholar
- Fleming DF (2004) Seasonal Habitat Use and Experimental Videoenumeration of Rainbow Trout within the Gulkana River Drainage. Alaska Department of Fish and Game, Fishery Data Series No. 04-04Google Scholar
- Goudet J (2001) FSTAT, a program to estimate and test gene diversities and fixation indices, version 2.9.3. Available from http://www.unil.ch/izea/softwares/fstat.htmlGoogle Scholar
- Kostow K (2003) Factors that Influence Evolutionary Significant Unit Boundaries and Status Assessment in a Highly Polymorphic Species, Oncorhynchus mykiss, in the Columbia Basin. Oregon Department of Fish and Wildlife Information, Report No. 2003-04, 122pGoogle Scholar
- NOAA (2003) Updated status of Federally listed ESUs of West Coast salmon and steelhead. West Coast Salmon Biological Review Team. NOAA Fisheries Northwest and Southwest Fisheries Science Centers. http://www.nwfsc.noaa.gov/trt/brtrpt.htmGoogle Scholar
- O’Connell M, Danzmann RG, Cornuet J-M, Wright JM, Ferguson MM, (1997) Differentiation of rainbow trout (Oncorhynchus mykiss) populations in Lake Ontario and the evaluation of the stepwise mutation and infinite allele mutation models using microsatellite variability. Can. J. Fish. Aquat. Sci. 54: 1391–1399CrossRefGoogle Scholar
- Stark TC (1999) Spawning Stocks and Juvenile Summer Habitat of Rainbow Trout and Steelhead, Gulkana River, Alaska. MSc Thesis, University of Alaska, FairbanksGoogle Scholar
- Wuttig KG, Fleming DF, Olsen J (2004) Stock Status and Population Biology of the Copper River Steelhead. Alaska Department of Fish and Game Fishery Data Series No. 04-18, 59pGoogle Scholar