Genetic Effect on the Dynamics of a Model of Pink (Oncorhynchus gorbuscha) and Chum (O. keta) Salmon

1984 ◽  
Vol 41 (10) ◽  
pp. 1446-1453 ◽  
Author(s):  
William W. Smoker

Different stock dynamics result from genetic and nongenetic mechanisms of determination of maturation age of chum salmon (Oncorhynchus keta) in a model of interacting pink (O. gorbuscha) and chum salmon stocks. When the model is disturbed from equilibrium by low survival in one pink salmon line, the genetic mechanism (high heritability of maturation age) leads to biennial cycles of numbers of even-aged chums and of numbers of pinks, similar to observed cycles. The nongenetic mechanism (zero heritability of maturation age) results in a new equlibrium at which neither stock cycles. When one pink salmon line is completely removed the genetic mechanism leads to biennial cycles of abundance of even-aged chums; the nongenetic mechanism does not lead to such cycles. These effects persist at intermediate values of heritability of maturation age and in spite of stochastic variability. The model is an adaptation of the Ricker curve to two interacting stocks, the recruitment for each depending on the density of both.

1993 ◽  
Vol 71 (6) ◽  
pp. 1270-1274 ◽  
Author(s):  
Terry D. Beacham

Pink (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) fry have the potential for significant interactions in estuarine and nearshore waters of the Fraser River. Potential competitive effects were investigated by rearing both species for 60 d from fry emergence in monoculture and five duoculture environments (0, 10, 25, 50, 75, 90, and 100% pink salmon, and 100, 90, 75, 50, 25, 10, and 0% chum salmon, respectively), with the total number of fish in each environment constant. As the relative abundance of chum salmon increased, the mean weight of both pink and chum salmon declined, and reduced phenotypic variation in weight was observed. No marked trends in survival were observed in either species, but there was some indication that pink salmon survival was higher at intermediate relative densities of pink and chum salmon. Pink salmon biomass increased from 0.8 to 1.8%/d depending on the environment, and chum salmon biomass increased from 3.2 to 3.8%/d.


2006 ◽  
Vol 120 (2) ◽  
pp. 199
Author(s):  
Alexandra Morton ◽  
Rob Williams

Recent recurring infestations of Sea Lice, Lepeophtheirus salmonis, on juvenile Pacific salmon (Oncorhynchus spp.) and subsequent annual declines of these stocks have made it imperative to identify the source of Sea Lice. While several studies now identify farm salmon populations as sources of Sea Louse larvae, it is unclear to what extent wild salmonid hosts also contribute Sea Lice. We measured Sea Louse numbers on adult Pink Salmon (Oncorhynchus gorbuscha) migrating inshore. We also measured Sea Louse numbers on wild juvenile Pink and Chum salmon (Oncorhynchus keta) migrating to sea before the adults returned, and as the two age cohorts mingled. Adult Pink Salmon carried an average of 9.89 (SE 0.90) gravid lice per fish, and thus were capable of infecting the adjacent juveniles. Salinity and temperature remained favourable to Sea Louse reproduction throughout the study. However, all accepted measures of Sea Louse infestation failed to show significant increase on the juvenile salmon, either in overall abundance of Sea Lice or of the initial infective-stage juvenile lice, while the adult wild salmon were present in the study area. This study suggests that even during periods of peak interaction, wild adult salmon are not the primary source of the recent and unprecedented infestations of Sea Lice on juvenile Pacific Pink and Chum salmon in the inshore waters of British Columbia.


2007 ◽  
Vol 116 (4) ◽  
pp. 298-304 ◽  
Author(s):  
R.B. Phillips ◽  
J. DeKoning ◽  
M.R. Morasch ◽  
L.K. Park ◽  
R.H. Devlin

1983 ◽  
Vol 40 (4) ◽  
pp. 426-435 ◽  
Author(s):  
Nicholas J. Bax

The average daily loss in numbers from a group of fluorescently marked, hatchery-reared, juvenile chum salmon (Oncorhynchus keta) remaining in the nearshore zone following their release from the hatchery into southern Hood Canal, Washington State, was estimated at 38–49%. This estimated loss was then adjusted by the estimated maximum emigration of marked fish from the sampling area and the average daily mortality over a 2- and a 4-d time period estimated at between 31 and 46%. These estimates are an order of magnitude higher than estimates of the average daily mortality of naturally emigrating juvenile pink salmon (O. gorbuscha) from the Bella Coola River, British Columbia, over a 40-d time period (Parker 1968). The two studies are contrasted and it is suggested that daily mortality is highly variable over the 40 d subsequent to saltwater entry, with mortality higher initially, particularly for those fish remaining close to their point of saltwater entry.


2021 ◽  
Vol 201 (3) ◽  
pp. 702-711
Author(s):  
O. V. Zelennikov ◽  
T. A. Schneider ◽  
M. Yu. Stekolshchikova

State of blood cells is examined for juveniles of pink and chum salmon sampled from Lesnoy Pugachevsky, Taranaisky and Okhotsky hatcheries in Sakhalin in May-June of 2018 and 2019 and caught in the Ochepukha, Pugachevka and Taranay Rivers during their catadromous migration to the sea. Both hatchery and wild juveniles of both species were characterized by high adaptive capabilities evidenced with high content of young forms of erythrocytes in the blood (17.0–31.0 %), significant portion of lymphocytes (60.8–92.0 %), and small number of neutrophils. The high adaptive capabilities were confirmed in the experiment, when juveniles of pink salmon were placed in the seawater without preliminary acclimation, but noticeable changes in the state of blood cells were not revealed both for wild and hatchery-reared specimens. Proportion of different blood cells was highly variable for juveniles of both artificial and natural origin but was more similar between the fry hatched at the same hatcheries or in the same rivers. A case of increased number of neutrophils was noted in 2019 for certain groups of juveniles, with total increasing of platelets in the blood that was explained by an external influence on the juveniles.


2010 ◽  
Vol 84 (4) ◽  
pp. 434-440 ◽  
Author(s):  
J. Suzuki ◽  
R. Murata ◽  
K. Sadamasu ◽  
J. Araki

AbstractWe investigated the risk of diphyllobothriasis from ingestion of wild Pacific salmon in Japan by surveying Diphyllobothrium plerocercoids in 182 salmon samples obtained from Japan. The plerocercoids were not detected in chum salmon (Oncorhynchus keta) (0/26), called Akizake in Japan, caught between September and November. However, the detection rate of plerocercoids in chum salmon, called Tokishirazu in Japan, caught between early April and June, was 51.1% (24/47) with an average of two plerocercoid larvae per fish. The detection rates of cherry salmon (Oncorhynchus masou) and pink salmon (Oncorhynchus gorbuscha) were 12.2% (10/82) and 18.5% (5/27), respectively, and the average number of plerocercoids per fish was 0.45 (37 larvae/82 fishes) and 0.22 larvae (6 larvae/27 fishes), respectively. Plerocercoids isolated from O. keta and O. masou were identified as Diphyllobothrium nihonkaiense on the basis of molecular analysis of the cox1 and nad3 genes. Moreover, four tapeworms (three from O. keta and one from O. masou) were obtained by infecting golden hamsters with plerocercoids. The morphological features of these tapeworms were similar to those of D. nihonkaiense isolated from humans. Therefore, we think that O. keta and not O. masou is the most important source of plerocercoid infections in Japan.


2006 ◽  
Vol 63 (9) ◽  
pp. 2076-2086 ◽  
Author(s):  
Morgan D Hocking ◽  
Thomas E Reimchen

Anadromous Pacific salmon (Oncorhynchus spp.) subsidize terrestrial food webs with their nutrients and carcasses, a process driven largely by selective foraging by bears (Ursus spp.). We quantify wildlife transfer of salmon carcasses to riparian zones on two watersheds in coastal British Columbia and estimate total terrestrial fly production from remnant carcasses. Large-bodied chum salmon (Oncorhynchus keta) were transferred into the forest at a greater rate than were pink salmon (Oncorhynchus gorbuscha) (chum salmon mass = 6089–11 031 kg, 16%–48% of salmon run; pink salmon mass = 2266–2808 kg, 4%–6% of salmon run). Blow flies (genus Calliphora) and other Diptera dominated colonization (>90% of salmon carcasses). Between the two watersheds, 196 and 265 g of Calliphora larvae per metre of spawning length (4 and 7 million larvae for whole watersheds) were generated from salmon carcass transfer. Stable isotope analysis of δ15N and δ13C of spring-emerging adult Calliphora revealed that >80% of individuals had salmon-based signatures. Flies are a dominant consumer and vector of salmon nutrients in terrestrial habitats and supplement the diet of at least 16 vertebrate and 22 invertebrate species. Anticipated further declines of salmon in the North Pacific can be expected to further erode the complex associations coupling marine and terrestrial ecosystems.


Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Terry D. Beacham

A factorial mating design was employed in which five males were mated to each of five females in each of two stocks for both pink and chum salmon. The resulting embryos and alevins were incubated at constant water temperatures of 4, 8, and 16 °C for pink salmon and 3, 8, and 15 °C for chum salmon. Variation among families in alevin and fry survival rates, hatching, button-up time, length, and weight was the least at 8 °C. Heritability of traits directly correlated with fitness, such as survival rates and button-up time, was low at all temperatures (h2 ≤ 0.25). Maternal effects could account for a substantial portion of the variation in alevin and fry size characters. Nonadditive genetic variance accounted for more of the variation in fry size characters than in those of alevins. Negative genetic correlations were observed between embryo survival and subsequent alevin size and between hatching time and subsequent alevin and fry size. Genotype–temperature interactions could underlie a substantial amount of phenotypic variation in the developmental characters examined for both species.Key words: development, genetic variation, quantitative genetics, salmon.


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