Environmental Biology of Fishes 69: 1–5, 2004. © 2004 Kluwer Academic Publishers. Printed in the Netherlands. Introduction to genetics of subpolar fish and invertebrates A.J. Gharrett a , S. Keller b , R.G. Gustafson c , P. Johnson d , J.L. Nielsen e , J.E. Seeb f , L.W. Seeb f , W.W. Smoker a , G.H. Thorgaard g & R.L. Wilmot d a Fisheries Division, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 11120 Glacier Highway, Juneau, AK 99801, U.S.A. (e-mail: ffajg@uaf.edu) b Alaska Sea Grant College Program, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775-5040, U.S.A. c National Marine Fisheries Service, Northwest Fisheries Science Center, Conservation Biology Division, 2725 Montlake Blvd. E, Seattle, WA 98112, U.S.A. d National Marine Fisheries Service, Auke Bay Laboratory, Alaska Fisheries Science Center, 11305 Glacier Highway, Juneau, AK 99801, U.S.A. e U.S. Geological Survey, Alaska Science Center, 1011 E. Tudor Road, Anchorage, AK 99503, U.S.A. f Alaska Department of Fish and Game, Commercial Fisheries Division, 333 Raspberry Road, Anchorage, AK 99518, U.S.A. g School of Biological Sciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164-4236, U.S.A. Key words: quantitative genetics, population genetics, molecular genetics, aquaculture, systematics, wild–hatchery interactions This 20th Wakefield Symposium, ‘The genetics of subpolar fish and invertebrates’, is the successor of the 11th Wakefield Symposium, ‘Genetics of sub- arctic fish and shellfish’, which was held in Juneau, Alaska in 1993. In the introduction to that sympo- sium (Gharrett & Smoker 1994), it was noted that: ‘beginning in the 1960s, modern tools of genetic analysis began to be broadly applied in fisheries sci- ence’, and that ‘within the past decade (referring to the 1980s), fisheries genetics had entered the main- stream of fisheries resource utilization’. That obser- vation may be an understatement in today’s world of fisheries science. Once-vigorous fisheries in many parts of the world have failed, growing demand for fisheries products has led to full utilization of many remaining capture resources and is driving an increase in aquaculture productivity, and the role of aquacul- ture has increased dramatically (FAO 2002). Looming over concerns of lost stocks and persistent erosion of genetic variability are predictions of global warming, which may further tax genetic resources. One of the consequences of these developments is an increased interest in and reliance on genetic applications to many aspects of fisheries management, aquaculture, and conservation. In addressing those concerns, fisheries scientists have increased their attention to the genetics of fish and fish populations; the number of fish genetics citations has increased fourfold in the last decade (Figure 1). In addition to the increased attention, the application of sophisticated genetic analysis tools, such as studies of mitochondrial DNA (mtDNA) and microsatellites, have nearly caught up with the more traditional allozyme studies in annual citations (Figure 1). One of the predominant themes of both symposia was the descriptive study of population structure. Descriptive studies are an important step in develop- ing management or conservation plans because they can provide markers for use in stock identification programs and because they can identify distinct pro- ductivity units (the geographical scale of such units) in species that do not have convenient or obvious geographical boundaries, such as many marine species. Analyses of allozyme variation, which dominated early fisheries genetics research, still provide valuable