ISSN:0706-652X    

DOI:10.1139/f94-287

出版商:NRC Research Press    

年代:1994

数据来源: NRC

ISSN:0706-652X    

DOI:10.1139/f94-288

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

Variation of size, particularly among males, has a significant genetic basis in pink salmon (Oncorhynchus gorbuscha) in Auke Creek, southeast Alaska. Heritability (h2), based on variance components of 118 full sib − 59 paternal half sib families of mature fish tagged as fry with coded micro wires, are higher in males (h2length: 0.8 ± 0.3 (mean ± SE);h2weight: 0.6 ± 0.2, based on sire effect) than in females (h2length: 0.3 ± 0.2;h2weight: 0.4 ± 0.2). Realized heritability probably would be smaller because of environment variability between brood years in factors affecting size and growth. Estimates based on regression of offspring means on fathers' values are smaller (h2length: 0.4 ± 0.1 in males; 0.2 ± 0.1 in females;h2weight: 0.0 in males and 0.1 ± 0.1 in females). Estimates of genetic, environmental, and phenotypic correlations of length and weight are all >0.7 (SEs <0.1). Estimates of genetic correlation between length and day of migration from the sea are near 0.4 ± 0.2; estimates of environmental and phenotypic correlations between these traits are smaller (<0.2, SEs <0.1).

ISSN:0706-652X    

DOI:10.1139/f94-289

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

Survival to initiation of feeding and early freshwater growth were measured for both diploid (2N) and triploid (3N) Atlantic salmon (Salmo salar) and 2N and 3N hybrids between female Atlantic salmon and male brown trout (Salmo trutta) to evaluate the triploid hybrid's potential for commercial culture. Crosses were made in 1990 and 1991 and triploidy was induced by heat shock. Average survival to initiation of feeding generally did not differ among the 2N Atlantic salmon and hybrids within years, nor between the 3N crosses within years. Average survival to initiation of feeding of the 3N Atlantic salmon and hybrids relative to the corresponding 2N crosses was reduced by 2 and 9%, respectively, in 1990, and by 55 and 62%, respectively, in 1991. Five freshwater growth trials were conducted to compare the different crosses. Results indicated no consistent differences in relative growth rates, although the hybrids demonstrated greater variability in growth at age 0+.

ISSN:0706-652X    

DOI:10.1139/f94-290

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

We investigated the viability and seawater tolerance of all possible combinations of triploid and diploid hybrids between chinook (Oncorhynchus tshawytscha), chum (O.keta), and pink salmon (O.gorbuscha) in two brood years. Triploidy (induced by heat shock shortly after fertilization) was determined by flow cytometry of blood taken from a sample of the fish. A factorial mating design was used to estimate the effects of cross, heat shock (ploidy), and their interaction. With the exception of the chinook (♂) × chum (♀) cross, all combinations produced offspring that survived to yolk absorption. Survival of heat-shocked groups was lower than that of diploid controls at the eyed stage and at hatching, but not different from diploids between hatching and yolk absorption. Induced triploidy did not increase the viability of interspecies hybrids. The level of triploid induction averaged across all heat-shocked crosses was 88% in one year and 95% in the other. Seawater tolerance (measured by 24-h seawater challenge survival) was higher in chinook hybrids with pink and chum salmon than in chinook controls. Seawater tolerance did not differ between diploid controls and heat-shocked triploid groups. Combinations that had seawater tolerance shortly after yolk absorption include chinook × pink, pink × chinook, and chum × chin

ISSN:0706-652X    

DOI:10.1139/f94-291

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

Sterile hybrid and triploid fish may provide hatchery programs with a tool to reduce the risk of genetic contamination of wild stocks, provided these fish have acceptable performance characteristics. We examined growth, survival, and deformities in diploid and triploid families of coho salmon (Oncorhynchus kisutch) and hybrids between coho salmon females × chinook salmon (O.tshawytscha) males. Data were collected from the half-sibling families through day 387. A reparameterized Gompertz growth model showed that conspecific coho salmon grew faster than hybrids, regardless of ploidy. No difference in growth rates was found between diploids and triploids. Abnormalities were significantly associated with the male parent but not with ploidy component, in contrast to previous observations of reduced deformity occurrence in triploid hybrids. Food conversion was better for conspecifics than hybrids during initial feeding, but not different during the second half of the experiment. No ploidy or cross × ploidy interaction effects on food conversion efficiency were observed. Finally, conspecifics had better posthatching survival than hybrids, regardless of ploidy. Of the treatments studied, conspecific triploid coho salmon may be the most viable alternative for sterile fish production: they performed as well as the conspecific diploids and better than either diploid or triploid hybrids.

ISSN:0706-652X    

DOI:10.1139/f94-292

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

The findings indicate that mosaicism does occur in triploids and especially in triploid hybrids. Immature diploid and triploid salmon were obtained from the University of Alaska – National Marine Fisheries Service. These were fixed in 10% buffered formalin and blocks taken from various tissues including kidney, liver, spleen, and gonads. The paraffin blocks were sectioned at 4 μm and stained with hematoxylin and eosin for histologic evaluation and to quantitate nuclear DNA. The slides for DNA evaluation were stained using the Cell Analysis Systems, Inc. (CAS, Elmhurst, IL) kit following Feulgen hydrolysis. The Cell Analysis Systems, Inc. (Model 200) computer-assisted image analyzer was used for DNA quantitation. An attempt was made to evaluate the frequency of mosaicism, ploidy variation in somatic and gonadal tissues of triploids and hybrids as compared with normal diploids. Hepatic ploidy variation, normal in adult animals, was not present in these specimens. However, in gonads there was evidence of increased mosaicism among the triploids. Because of mosaicism in gonadal tissue, sterility of triploids cannot be presumed with certainty at this stage. Further studies are planned to examine this and other questions raised by these results.

ISSN:0706-652X    

DOI:10.1139/f94-293

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

We found that salt water induces ploidy alterations in salmonid embryos. Flow cytometry analysis revealed significantly higher frequencies of haploids, triploids, heteroploid mosaics, and aneuploids in rainbow trout (Oncorhynchus mykiss) embryos experimentally exposed to salt water from fertilization to the two- and eight-cell stages of development. Heteroploid mosaics have been reported in diploid and triploid salmonid hybrids, although none were observed in the triploid coho salmon or diploid and triploid coho salmon (O.kisutch) × chinook salmon (O.tshawytscha) hybrids we examined. No mosaics were observed in intertidally spawned pink salmon (O.gorbuscha) embryos. Salt water could induce ploidy alterations by causing chromosome segregation errors during meiosis, mitosis, or both. Heteroploid embryos appeared morphologically normal although they may possess physiological deficiencies not immediately apparent.

ISSN:0706-652X    

DOI:10.1139/f94-294

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

Allozymes from 46 loci were analyzed from chum salmon (Oncorhynchus keta) collected at 61 locations in southeast Alaska and northern British Columbia. Of the 42 variable loci, 21 had a common allele frequency <0.95. We observed significant heterogeneity within and among six regional groups: central southeast Alaska, Prince of Wales Island area, southern southeast Alaska – northern British Columbia, north-central British Columbia, and two groups in the Queen Charlotte Islands. Genetic variation among regions was significantly greater than within regions. The three island groups were distinct from each other and from the mainland populations. Allele frequencies were stable over time in 14 of 15 locations sampled for more than 1 yr. The geographic basis for heterogeneity among regions is confounded in part by spawning-time differences. The Prince of Wales and Queen Charlotte populations spawn in the fall; the mainland populations spawn mainly in the summer, although some overlap exists. Overall, most genetic diversity (97%) occurred within sampling locations; the remaining diversity was distributed almost equally within and among regions. Our genetic data may provide fishery managers a means to estimate stock composition in the mixed-stock fisheries near this boundary between the United States and Canada.

ISSN:0706-652X    

DOI:10.1139/f94-295

出版商:NRC Research Press    

年代:1994

数据来源: NRC

摘要:

We used starch-gel electrophoresis to examine over 13 000 adult chum salmon,Oncorhynchus keta, from 153 collections at 105 locations in Washington, Oregon, and southern British Columbia from 1985–92. We identified 39 variable loci and 36 monomorphic loci. In general, alleles that occurred at a frequency > 10% were found in all locations and were temporally stable within locations. Localized alleles usually occurred at a frequency <6%. Significant allele frequency differences were found among chum salmon populations with different spawning times (summer, fall, and winter), even within the same watershed, and among populations of the same spawning time in different regions. Significant among-population diversity was also found within regions. Multidimensional scaling and UPGMA cluster analysis grouped populations by geography and run-timing, except where past stock transfers have resulted in interbreeding of hatchery and wild fish. These analyses indicate that both geography and spawning time are important isolating mechanisms and that, compared with the other populations, summer-run chum salmon from the Strait of Juan de Fuca and Hood Canal are a distinct evolutionary lineage. This information is currently being used to conserve the genetic diversity of wild chum salmon and manage mixed-stock fisheries.

ISSN:0706-652X    

DOI:10.1139/f94-296

出版商:NRC Research Press    

年代:1994

数据来源: NRC