Heterozygosity and morphological variability of pink salmon (Oncorhynchus gorbuscha) from southern British Columbia and Puget Sound

1985 ◽  
Vol 27 (5) ◽  
pp. 571-579 ◽  
Author(s):  
Terry D. Beacham ◽  
Ruth E. Withler

We compared variability in gill raker number and four morphometric characters with heterozygosity at enzymatic loci within and among populations of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Among individuals, there was no relationship between levels of heterozygosity at eight electrophoretic loci and degree of meristic or morphometric variation. Decreased phenotypic variance was not associated with increased heterozygosity. Among populations of pink salmon, increased levels of average heterozygosity were not associated with decreased phenotypic variation. Our results do not support the hypothesis that more heterozygous individuals are less phenotypically variable than more homozygous ones as a result of genetic homeostasis and a canalisation of morphology during development. Genetic distances between pairs of pink populations were significantly correlated with pairwise Mahalanobis distances derived from meristic characters (gill rakers) and less strongly correlated with distances derived from morphometric characters. Pink salmon are morphometrically adapted to the natal stream environment, whereas biochemical and meristic characters in these populations may be less affected differentially by local selective forces.Key words: salmon, electromorphs, homeostasis, genetic variability, heterozygosity.

1985 ◽  
Vol 63 (2) ◽  
pp. 366-372 ◽  
Author(s):  
Terry D. Beacham

Variation in the number of gill rakers and four morphometric characters was examined for 4 stocks from the even-year brood line and 20 stocks from the odd-year brood line of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Significant differences in gill-raker frequencies were observed among stocks within each brood line, but differences were greater between the brood lines than within each brood line. Sizes of the morphometric characters standardized to a body length of 419 mm were also variable among stocks within a brood line, but stocks spawning in rivers in the same region in alternate years were more similar morphometrically than to those spawning in different regions. It is suggested that patterns of meristic and morphometric variability are reflective of genetic differences, with meristic variability illustrating the genetic differences between the brood lines, and morphometric variability reflecting adaptation to local water velocity conditions in the streams the stocks return to during spawning.


1985 ◽  
Vol 42 (9) ◽  
pp. 1474-1483 ◽  
Author(s):  
Terry D. Beacham ◽  
Ruth E. Withler ◽  
Allan P. Gould

We used electrophoresis to examine genetic variability at 12 loci for 4 even-year broodline stocks and at 14 loci for 21 odd-year broodline stocks of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Allelic frequencies were most heterogeneous between the two pink salmon broodlines, but within the odd-year broodline, Fraser River, Canadian non-Fraser, and Puget Sound pink salmon had significantly different allelic frequencies at some loci. Canadian non-Fraser River stocks had the greatest heterogeneity of allelic frequencies within a region, whereas the Fraser River stocks had the least amount of heterogeneity. There was no significant two-locus linkage disequilibrium for the pink salmon stocks surveyed. Cluster analyses by allelic frequencies indicated that Fraser River, Canadian non-Fraser, and Puget Sound stocks were reasonably distinctive. We used differences in genotypic frequencies at 11 loci (3 were duplicated loci) to estimate stock composition of these three groups of pink salmon in mixtures in which the true compositions were known, and we were able to compare the accuracy and precision of our estimates with respect to mixture size and stock composition. We estimated that 100% of pink salmon sampled in a test fishery in Thompson Sound were of Canadian non-Fraser origin.


1991 ◽  
Vol 69 (2) ◽  
pp. 274-278 ◽  
Author(s):  
Terry D. Beacham

Heterozygosity of 26 pink salmon (Oncorhynchus gorbuscha) families was compared with family survival rates up to 410 d after fry emergence and also with asymmetry of pectoral and pelvic fin ray numbers. There was no significant association between heterozygosity calculated at six electrophoretic loci and either survival rate or asymmetry in fin ray number at any time during the 410-d rearing period. More heterozygous families did not have higher survival rates than less heterozygous families, and they did not have less asymmetry in the fin ray characters. Heritabilities of 11 morphometric characters were, on average, lower than the heritabilities of the 2 meristic characters examined. There is no evidence yet to indicate that increased heterozygosity results in increased canalization of morphology in pink salmon.


1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.


1967 ◽  
Vol 24 (11) ◽  
pp. 2321-2338 ◽  
Author(s):  
M. C. Healey

During May and June 1966, the migration of pink salmon fry from the Bella Coola River was studied in Burke Channel, British Columbia. The movement of pink fry down Burke Channel was saltatory. Short periods of active migration were interspersed with longer periods when the fry did not migrate and accumulated in bays. Fry were sampled from these accumulations and their ability to orient using celestial cues was examined. During the early morning, fry tended to prefer directions at right angles to their direction of migration, but at other times of the day preferred the direction of migration. The preference for the direction of migration was strongest at midday. Fry were better oriented on clear days than on cloudy days. These data indicate that fry may use celestial cues to find directions during their oceanic migrations.


1992 ◽  
Vol 49 (7) ◽  
pp. 1294-1304 ◽  
Author(s):  
Murdoch K. McAllister ◽  
Randall M. Peterman ◽  
Darren M. Gillis

Since 1950, stocks of British Columbia pink salmon (Oncorhynchus gorbuscha) have shown up to a 34% decrease in mean adult body weight, causing significant reduction in economic value of commercial harvests. Previous research suggests that this trend is due to size-selective harvesting of large fish, but changes in oceanographic conditions are a plausible alternative. Corrective action by management agencies requires that the true causal mechanism be identified. We therefore examined several possible designs for a large-scale fishing experiment devised to test the size-selective fishing hypothesis. These designs would generate accurate and precise field estimates of the heritability (h2) of growth rate, which is important because it, in combination with the selection differential (D) caused by fishing, determines how rapidly body size changes. Monte Carlo simulations showed that block designs with three to six spatial replicates and relatively short durations generated high statistical power. For example, for h2 = 0.22, D = 0.25 kg, and four spatial replicates, an 8-yr experiment resulted in power = 0.87, which gave a SE < 0.10 for h2 = 0.22. We conclude that some experimental designs have good potential to test the possible effects of size-selective fishing on mean adult size of British Columbia pink salmon.


1981 ◽  
Vol 38 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Jean-Guy J. Godin

Stomach analyses showed that pink salmon fry fed mainly during daylight hours in the littoral zone of Departure Bay and Hammond Bay, British Columbia, in May. Although the diurnal feeding patterns of the fish differed slightly between the two bays, maximum mean prey biomass in the fishes' stomachs occurred near or at dusk in both bays. Daily rations consumed by Departure Bay and Hammond Bay fish were estimated to be 13.1 and 6.6% of their dry body weight, respectively. The fry consumed similar prey items in both bays, but in differing proportions. Harpacticoid copepods, copepod nauplii, and barnacle larvae comprised numerically 93.1 and 86.2% of the diets of Departure Bay and Hammond Bay fish, respectively. About 38% of the diet of Departure Bay fish and 51% of the diet of Hammond Bay fish comprised epibenthic prey, mainly harpacticoid copepods. The data provide additional support for the importance of the detritus-microbe-consumer type food chain supporting the production of pink salmon during their early period of marine residency.Key words: pink salmon, feeding behavior, daily rhythm, diet, ration, British Columbia


1978 ◽  
Vol 56 (10) ◽  
pp. 2235-2238 ◽  
Author(s):  
J. C. Pearson ◽  
L. Margolis ◽  
N. P. Boyce

The metacercaria of Galactosomum phalacrocoracis (Trematoda: Heterophyidae), collected from Oncorhynchus gorbuscha (Walbaum) from coastal waters of British Columbia, is described.


1975 ◽  
Vol 32 (12) ◽  
pp. 2343-2356 ◽  
Author(s):  
W. H. Lear

Five transplants of eyed eggs of Pacific pink salmon (Oncorhynchus gorbuscha) were made between streams in southern British Columbia and North Harbour River, Newfoundland. Quantities transplanted were 0.25 million in 1959, 2.5 million in 1962, 3.4 million in 1964, 3.3 million in 1965, and 5.9 million in 1966. Adult returns from these transplants were 1, 49, 638, 8500, and 2426 during 1961, 1964, 1966, 1967, and 1968, respectively. Since 1969, returns have been the progeny of naturally spawning fish and have steadily declined in numbers. The reasons for failure of the transplant are not certain, but possibilities include the following: predation on the fry by brook trout and possibly eels in North Harbour Pond and estuary; unfavorable surface temperatures in the river during the fry run; predation by herring on fry in St. Mary’s Bay; year-class failure of the even-year stocks that were introduced; unsuitability of the donor stocks with respect to migration patterns and homing behavior; inadequate numbers of eggs were transplanted to produce populations required to maintain runs in anything below optimum environmental conditions.


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