faculty listing

A Photo of  Anthony Gharrett

Contact Information

Fisheries Division
325 Lena Point
17101 Point Lena Loop Rd
UAF Fisheries Division
Juneau, AK 99801-8344
Phone: (907) 796-5445
Fax: (907) 796-5447
a.gharrett@alaska.edu

Anthony Gharrett Professor Emeritus

Fish and Fisheries Genetics • Fisheries Conservation • Fisheries Systematics

Specialty

  • population genetics of salmon and rockfish

Research Overview

Genetics is important in both the management and culture of fishes as well as for understanding their biology and evolution. Populations are molded by the environments, or series of environments, to which they are exposed. Natural selection favors traits that optimize their survival and production; and, consequently, populations become "locally adapted" and tend to diverge genetically from other populations. Divergence often increases over geographic distance. One consequence of local adaptation is that translocations and hatchery strays may jeopardize locally pre-adapted populations. Our research has examined the effect on survival and other "fitness" characteristics of hybridizing genetically distinct populations. We have documented "outbreeding depression" in hybrids between spatially separated pink salmon populations and are now looking at seasonally separated populations.
The geographic distribution of genetic variation in species provides a means to track the recent (evolutionary scale) post-Pleistocene colonization of salmon and even marine species. We have conducted phylogeographic studies of both salmon and rockfish species. Moreover, persistence of geographically-based genetic structure under geographic or oceanographic conditions in which one would expect wide dispersal of pelagic larvae and juveniles or long-lived adults is evidence of limited dispersal. That geographic scale of that structure should provide managers with guidance for management area size. Managing at larger scales risks local depletions.
Unique heritable characteristics may define a population or group of populations in a geographic region. Recently, western Alaskan chum salmon returns have declined. At the same time, global climate change has affected both freshwater and marine habitats in Alaska, the pollock fishery has captured incidentally large numbers of chum salmon and many Asian chum salmon migrate through the eastern Bering Sea. To understand the causes(s) of the decline, the origins of salmon intercepted in marine waters must be determined. We are currently participating in developing species-wide genetic information on chum salmon populations that can provide markers needed to determine natal origins.
Recent advances in DNA technology have introduced new, powerful techniques for resolving genetic differences in mitochondrial DNA and nuclear DNA sequences. We are currently developing methods and markers to improve DNA sequence-based methods to investigate salmon and rockfish population and evolutionary genetics.

Publications

Gharrett, A.J., R.J. Riley, and P.D. Spencer. In press. Genetic analysis reveals restricted dispersal of northern rockfish along the Bering Sea and Aleutian Islands shelf break. Transaction of the American Fisheries Society 000:000-000.

Palof, K.J., J. Heifetz, and A.J. Gharrett. 2011. Geographic structure in Alaskan Pacific ocean perch (Sebastes alutus) indicates limited life-time dispersal. Marine Biology 158:779-792.
Garvin, M.R., and A.J. Gharrett. 2010.

Application of SNP markers to chum salmon Oncorhynchus keta: Discovery, genotyping, and linkage phase resolution. Journal of Fish Biology 77:2137–2162.

Garvin, M.R., K. Saitoh, and A.J. Gharrett. 2010. Application of Single Nucleotide Polymorphisms to Non-model species: A Technical Review. Molecular Ecology Resources 10:915-934.

Dann, T.H., W.W. Smoker, J.J. Hard, and A.J. Gharrett. 2010. Outbreeding depression after two generations of hybridizing Southeast Alaskan coho salmon populations? Transactions of the American Fisheries Society 139:1292–1305.

Geiger, H.J., I. Wang, P. Malecha, K. Hebert, W.W. Smoker, and A.J. Gharrett. 2007. What causes variability in pink salmon family size? Transactions of the American Fisheries Society 136:1688-1698.

Wang, I.A., S.E. Gilk, W.W. Smoker, and A.J. Gharrett. 2007. Outbreeding effect on embryo development in hybrids of allopatric salmon populations, a potential consequence of stock translocation. Aquaculture 272S1:S152-S160.

Flannery, B.G., J.K. Wenburg, and A.J. Gharrett. 2007. Evolution of mitochondrial DNA variation within and among Yukon River chum salmon populations. Transactions of the American Fisheries Society 136:902-910.

Garvin, M.R., and A.J. Gharrett. 2007. DEco-TILLING: An inexpensive method for SNP discovery that reduces ascertainment bias. Molecular Ecology Notes 7:735-746.

Li, Z., A.K. Gray, M.S. Love, T. Asahida, and A.J. Gharrett. 2006. Phylogeny of members of the rockfish (Sebastes) subgenus Pteropodus and their relatives. Canadian Journal of Zoology 84:527-536.

Gharrett, A.J., A.P. Matala, E.L. Peterson, A.K. Gray, and J. Heifetz. 2005. Two genetically distinct forms of rougheye rockfish (Sebastes aleutianus) are different species. Transactions of the American Fisheries Society 134:242-250.

Gilk, S.E., I.A. Wang, C.H. Hoover, W.W. Smoker, S.G. Taylor, A.K. Gray, and A.J. Gharrett. 2004. Outbreeding depression in hybrids between spatially separated pink salmon (Oncorhynchus gorbuscha) populations: Marine survival, homing ability, and variability in family size. Environmental Biology of Fishes 69:287-297.

Halupka, K.C., M.F. Willson, M.D. Bryant, F.H. Everest, and A.J. Gharrett. 2003. Conservation of population diversity of Pacific salmon in Southeast Alaska. North American Journal of Fisheries Management 23:1057-1086.

Churikov, D. and A.J. Gharrett. 2002. Comparative phylogeography of the two pink salmon broodlines: an analysis based on mitochondrial DNA genealogy. Molecular Ecology 11:1077-1101.

Gharrett, A.J., S. Lane, A.J. McGregor, and S.G. Taylor. 2001. Use of a genetic marker to examine genetic interaction among subpopulations of pink salmon (Oncorhynchus gorbuscha). Genetica 111:259-267.

Noll, C., N.V. Varnavskaya, E.A. Matzak, S.L. Hawkins, V.C. Midanaya, O.N. Katugin, C. Russell, N.M. Kinas, C.M. Guthrie III, H. Mayama, F. Yamazaki, B.P. Finney, and A.J. Gharrett. 2001. Analysis of contemporary genetic structure of even-year pink salmon, Oncorhynchus gorbuscha. Fishery Bulletin 99:123-138.

Gharrett, A.J., W.W. Smoker, R.R. Reisenbichler, and S.G. Taylor. 1999. Outbreeding depression in hybrids of even- and odd-broodline pink salmon (Oncorhynchus gorbuscha Walb.). Aquaculture 173:117-129.

McGregor, A.J., S. Lane, M.A. Thomason, L.A. Zhivotovsky, W.W. Smoker, and A.J. Gharrett. 1998. Migration timing, a life history trait important in the genetic structure of pink salmon. North Pacific Anadromous Fish Commission Bulletin No. 1:262-273.

Hebert, K.P., P.L. Goddard, W.W. Smoker, A.J. Gharrett. 1998. Quantitative genetic variation and genotype by environment interaction of embryo development rate in pink salmon (Oncorhynchus gorbuscha). Canadian Journal of Fisheries and Aquatic Science 55:2048-2057.

Geiger, H.J., W.W. Smoker, L.A. Zhivotovsky, and A.J. Gharrett. 1997. Variability of family size and heritability of marine survival in pink salmon have implications for conservation biology and human use. Canadian Journal of Fisheries and Aquatic Science 54:2684-2690.

Baker, T.T., A.C. Wertheimer, R.D. Burkett, R. Dunlap, D.M. Eggers, E.I. Fritts, A.J. Gharrett, R.A. Holmes, R.L. Wilmot. 1996. Status of Pacific salmon and steelhead escapements in Southeast Alaska. Fisheries 21:6-18.