Morphological Differences between Hatchery and Wild Populations of Coho Salmon (Oncorhynchus kisutch): Environmental versus Genetic Origin

1991 ◽  
Vol 48 (9) ◽  
pp. 1783-1791 ◽  
Author(s):  
D. P. Swain ◽  
B. E. Riddell ◽  
C. B. Murray

Previous studies have demonstrated morphological differences between hatchery-reared coho salmon (Oncorhynchus kisutch) of hatchery origin and wild-reared coho of wild origin. We tested for a genetic component to this divergence by comparing coho from hatchery and wild populations both reared in the same hatchery environment and for an environmental component by comparing hatchery- and wild-reared coho both of wild origin. As in the previous studies, wild-reared fish from wild populations had greater head dimensions, larger median fins, and deeper bodies than did hatchery-reared fish from hatchery populations. This difference, summarized by the first principal component (PC1) of the size-adjusted data, was related to rearing environment rather than to genetic differences between hatchery and wild populations. Genetic divergence (or maternal effects) did occur between hatchery and wild populations along PC2 and PC3, but this divergence was slight compared with the environmentally induced differences between the two types of fish along PC1.

1985 ◽  
Vol 42 (12) ◽  
pp. 2020-2028 ◽  
Author(s):  
Eric B. Taylor ◽  
J. D. McPhail

Ten populations of juvenile coho salmon, Oncorhynchus kisutch, from streams tributary to the upper Fraser River, the lower Fraser River, and the Strait of Georgia region were morphologically compared. Juveniles from coastal streams (Fraser River below Hell's Gate and the Strait of Georgia) were more robust (deeper bodies and caudal peduncles, shorter heads, and larger median fins) than interior Juveniles. Discriminant function analysis indicated that juvenile coho could be identified as to river of origin with 71% accuracy. Juvenile coho from coastal streams were less successfully classified as to stream of origin; however, juveniles could be successfully identified as either coastal or interior with 93% accuracy. Juvenile coho from north coastal British Columbia, Alaska, and the upper Columbia system also fitted this coastal and interior grouping. This suggests that a coastwide coastal–interior dichotomy in juvenile body form exists. Three populations (one interior and two coastal) were studied in more detail. In these populations the coastal versus interior morphology was consistent over successive years, and was also displayed in individuals reared from eggs in the laboratory. Adult coho salmon also showed some of the coastal–interior morphological differences exhibited by juveniles. We concluded that the morphological differences between coastal and interior coho salmon are at least partially inherited.


2002 ◽  
Vol 59 (7) ◽  
pp. 1100-1115 ◽  
Author(s):  
Laurie Weitkamp ◽  
Kathleen Neely

We investigated geographic variation in the ocean migration of coho salmon (Oncorhynchus kisutch) by examining recovery locations of 1.77 million coded-wire tagged fish from 90 hatcheries and 36 wild populations along the west coast of North America. Principal component, cluster, and similarity analyses were used to reveal both large- and small-scale variation in marine recovery patterns. We identified 12 distinct ocean distribution patterns, each associated with a particular geographic region. Despite these distinct patterns, however, fish from a given population were widely dispersed in the coastal ocean. Recovery patterns for tagged wild populations were consistent with those of hatchery populations from the same region, suggesting that marine distributions based on hatchery populations are reasonable proxies for distributions of wild populations. These region-specific distribution patterns suggest unappreciated life history diversity for coho salmon in the marine environment. When combined with region-specific adult size variation, they suggest migratory differences earlier in the ocean residence period as well. These results provide a novel framework with which to view geographic variation in salmon ocean ecology, conservation, and management.


1996 ◽  
Vol 74 (5) ◽  
pp. 851-857 ◽  
Author(s):  
P. A. Flett ◽  
G. Van Der Kraak ◽  
K. R. Munkittrick ◽  
J. F. Leatherland

We investigated the cause of the low survival to hatch of embryos of coho salmon (Oncorhynchus kisutch) from the Fairview, Pennsylvania, stock in Lake Erie. In 1988, survival to hatch of this stock was only 42%, whereas another Great Lakes coho salmon stock of similar genetic origin had an 84% survival to hatch. Laboratory cross-fertilization studies between the Fairview stock and a reference Lake Erie stock from Simcoe, Ontario, showed that eggs from the Fairview stock were the probable source of the low fertility. The presence of overripe eggs in Fairview females was associated with poor fertilization and low survival to hatch. Plasma gonadotropin II levels were similar in preovulatory females taken from the Fairview and Simcoe stocks, but testosterone and 17α, 20β-dihydroxy-4-pregnen-3-one levels were significantly lower in the Fairview females. Increasing the triiodo-L-thyronine (T3) content of the eggs by the administration of T3 to the preovulatory females did not enhance egg fertility. We propose that the low survival to hatch of the Fairview embryos is due to delayed oocyte maturation and ovulation and vent maturation, which may have been caused by exposure of the Fairview salmon to warmer water during the period of late ovarian maturation and migration.


2003 ◽  
Vol 60 (9) ◽  
pp. 1050-1056 ◽  
Author(s):  
Thomas Nickelson

To aid in the recovery of depressed wild salmon populations, the operation of hatcheries must be changed to reduce interactions of juvenile hatchery fish with wild fish. Evidence suggests that productivity of wild populations can be reduced by the presence of large numbers of hatchery smolts in lower rivers and estuaries that attract predators. An index of productivity based on the density-independent rate of reproduction of wild coho salmon (Oncorhynchus kisutch) in 12 Oregon coastal river basins and two lake basins was negatively correlated with the average number of hatchery coho salmon smolts released in each basin. The index of productivity was not significantly correlated with the average proportion of hatchery coho salmon in each naturally spawning population or with habitat quality. Alterations to hatchery programs that could encourage recovery of wild populations include (i) avoiding release of large numbers of smolts in areas with high concentrations of wild fish, (ii) decreasing the number of smolts released, and (iii) using a volitional release strategy or a strategy that employs smaller release groups spread temporally.


1986 ◽  
Vol 43 (12) ◽  
pp. 2443-2449 ◽  
Author(s):  
Thomas E. Nickelson ◽  
Mario F. Solazzi ◽  
Steven L. Johnson

We evaluated the effectiveness of using hatchery coho salmon (Oncorhynchus kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Juvenile and adult populations were monitored in 15 stocked and 15 unstocked streams from summer 1980 until summer 1985. During the summers following the planting of presmolts, the number of juveniles per square metre of pool surface area was higher in the stocked streams than in the unstocked streams. However, wild juveniles were significantly less abundant in the stocked streams during the 2 yr when density of wild juveniles was estimated separately from hatchery juveniles. Adult returns to the stocked streams were not significantly different from adult returns to the unstocked streams, but returns tended to be earlier in the stocked streams than in the unstocked streams. Despite similar numbers of adults per kilometre in the stocked streams and unstocked streams in the years the presmolts returned to spawn, the resulting densities of juveniles in the stocked streams were significantly lower than the densities of juveniles in the unstocked streams. We concluded that the early time of spawning of the hatchery coho salmon was largely responsible for their failure to rebuild the populations in the streams stocked with presmolts.


2020 ◽  
Vol 96 (2) ◽  
pp. 323-340
Author(s):  
Janet R Voight ◽  
Jessica A Kurth ◽  
Richard E Strauss ◽  
Jan M Strugnell ◽  
Louise A Allcock

Bathyal octopods of the genus Graneledone Joubin, 1918 in the northeast Pacific differ dramatically in skin texture. To test the hypothesis that these differences are associated with geography, we quantified the skin warts and tubercles of 50 specimens collected between 36°N and 46°N from 1116 to 2850 m depth. Using Principal Component Analysis (PCA), we analyzed the numbers of mantle and head warts, mantle and web tubercles, arm suckers, and inner and outer gill lamellae, adding head width as a size proxy. We used Canonical Correlation Analysis to explicitly test the relationship of morphology to depth and latitude. Sequences of 12S rRNA, 16S rRNA, and COI genes from 12 individuals quantified genetic divergence. PCA revealed correlated variation in head width, arm suckers, and gill lamella counts opposed by skin texture on PC1; PC2 showed correlated variation in skin texture opposed by gill lamella counts. Both components correlate with depth and latitude but, as most shallow specimens came from southern localities, the correlation with latitude may be artefactual. is relationship is corroborated by the canonical correlations. Octopods from greater depths are smaller than those from shallower depths, have rougher skin texture, and fewer suckers and gill lamellae. Clades of shallow and deep octopods show 0.8% genetic divergence in COI (Kimura two-parameter distance), not inconsistent with intraspecific differentiation. We conclude that the variation is likely clinal with depth. The observed morphological differences may result from differences in food availability and oxygen saturation with depth.


1990 ◽  
Vol 47 (3) ◽  
pp. 566-571 ◽  
Author(s):  
D. P. Swain ◽  
B. E. Riddell

We compared agonistic behavior of newly emerged coho salmon (Oncorhynchus kisutch) between hatchery and wild populations using mirror image stimulation tests. We used hatchery populations from two different regions of Vancouver Island B.C., each matched with a wild population from its region. In both comparisons, hatchery juveniles were more aggressive than wild juveniles. Rates of aggressive display increased with time since emergence for both hatchery and wild fish, as did the differences in behavior between the two types. By the sixth day of observation (13 d postemergence), the overall effect of fish type was highly significant for all aggressive behaviours. Since the individuals compared were reared from eggs under identical conditions, these differences are presumably genetic. Comparisons involved relatively few families from each population. However, because heritability was moderate to low within populations, and variance between population types exceeded variance among families within populations, these results indicate real differences at the population level. These results may have important implications for programs to rebuild wild populations using hatchery transplants and for selective breeding programs to develop domestic stocks of coho.


2018 ◽  
Vol 5 (04) ◽  
Author(s):  
SS SOLANKEY ◽  
ANIL K SINGH

Fifty one okra F1 hybrids (using 17 lines as female and 3 testers as male parent) were evaluated in RCBD design during two different consecutive seasons (summer and rainy). Phenotypic coefficient of variability (PCV) was higher than genotypic coefficient of variability (GCV) for all studied character exhibiting environmental effects on the expression of characters. Heritability (h2b) along with genetic advance per cent of mean was found highest for character YVMV (86.95% and 150.61%). All the 51 okra hybrids were grouped into 4 distinct clusters in which Cluster II was the largest cluster having 28 F1s (54.90% of total F1s) followed by Cluster I with 14 F1s (27.45% of total F1s). Out of the major 6 PCs, 4 principal components (PC1, PC2, PC3 and PC4) accounted with proportionate values of 22.61, 17.22, 11.87 and 10.63%, respectively and contributed 62.33 % of the cumulative variation having Eigen value more than one. Moreover, based on PCs and genetic divergence in Cluster I and Cluster IV for plant height, YVMV and number of fruit per plant is important to identify the best cross combination (Arka Abhay × Arka Anamika) in okra. Therefore, the best cross combinations for improvement in various economic traits can be recommended on the basis of genetic divergence and principal component analysis in okra.


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