Richard L. Wilmot

Genetic population structure of chum salmon in the Pacific Rim inferred from mitochondrial DNA sequence variation

We examined the genetic population structure of chum salmon, Oncorhynchus keta, in the Pacific Rim using mitochondrial (mt) DNA analysis. Nucleotide sequence analysis of about 500 bp in the variable portion of the 5′ end of the mtDNA control region revealed 20 variable nucleotide sites, which defined 30 haplotypes of three genealogical clades (A, B, and C), in more than 2,100 individuals of 48 populations from Japan (16), Korea (1), Russia (10), and North America (21 from Alaska, British Columbia, and Washington). The observed haplotypes were mostly associated with geographic regions, in that clade A and C haplotypes characterized Asian populations and clade B haplotypes distinguished North American populations. The haplotype diversity was highest in the Japanese populations, suggesting a greater genetic variation in the populations of Japan than those of Russia and North America. The analysis of molecular variance and contingency χ2 tests demonstrated strong structuring among the three geographic groups of populations and weak to moderate structuring within Japanese and North American populations. These results suggest that the observed geographic pattern might be influenced primarily by historic expansions or colonizations and secondarily by low or restricted gene flow between local groups within regions. In addition to the analysis of population structure, mtDNA data may be useful for constructing a baseline for stock identification of mixed populations of high seas chum salmon.

Status of Pacific Salmon and Steelhead Escapements in Southeastern Alaska

Abstract We evaluated the status of Pacific salmon and steelhead (Oncorhynchus mykiss) in southeastern Alaska. Of 9,296 spawning aggregates identified in this region, some data were available for 4,009 (43%), and 928 (10%) had sufficient information to analyze for escapement trend. Of those analyzed, 333 (36%) were increasing, 556 (60%) were stable, 37 (4%) were declining, and 2 (< 1%) showed precipitous declines. We evaluated risk of extinction of spawning aggregates using criteria similar to surveys outside Alaska. We rated 918 (99%) at no or low risk, 8 (∼ 1%) at moderate risk, and 2 (< 1%) at high risk. No spawning aggregates were identified as extinct based on our evaluation of escapement data dating back to 1960. Prior to 1960, two spawning aggregates, one sockeye salmon (0. nerka) and one chum salmon (0. keta), were identified as extinct based on responses to a postal questionnaire. The Alaska Department of Fish and Game grouped spawning aggregates into management units for each species. Management...

Genetic structure of wild chinook salmon populations of Southeast Alaska and northern British Columbia

Allozyme variation was used to examine population genetic structure of adult chinook salmon, Oncorhynchus tshawytscha, collected between 1988 and 1993 from 22 spawning locations in Southeast Alaska and northern British Columbia. Thirty-five loci and two pairs of isoloci were variable, and of these, 25 loci and one pair of isoloci expressed the most abundant allele with a frequency of less than or equal to 0.95 in at least one collection. A neighbor-joining (NJ) tree of genetic distances defined five regional groups: (1) King Salmon River (the only island collection), which has large allelic frequency differences from other populations in this study; (2) heterogeneous coastal populations from southern southeast Alaska; (3) transmountain collections from the Taku and Stikine Rivers on the eastern side of the coastal mountain range; (4) Chilkat River in northern Southeast Alaska; and (5) northern coastal Southeast Alaska, which consists of the Situk River and the Klukshu River, a tributary of the Alsek River. A second NJ tree that included collections from the Yukon River and British Columbia did not reveal any strong genetic similarity between Southeast Alaska and the Yukon River. The data suggest that Southeast Alaska may have been colonized from both northern and southern refugia following the last glaciation — a period of sufficient time to allow for isolation by distance to occur.

Introduction to Genetics of Subpolar Fish and Invertebrates

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 science’, 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.