Long-Term Peripheral Treatment of Immature Coho Salmon (Oncorhynchus kisutch) with Human Leptin Has No Clear Physiologic Effect

To test the olfactory hypothesis of salmon homing, fingerling coho salmon (Oncorhynchus kisutch) were exposed to low concentrations of an odorous synthetic chemical, morpholine during presmolt and smolting periods. Equal numbers of these fish were not exposed (controls). Both groups were stocked directly into Lake Michigan near Oak Creek, South Milwaukee Wisconsin. Another paired group of exposed and unexposed fish was released 13 km north of Oak Creek. During the adult spawning migration 18 mo later, morpholine was dripped into Oak Creek and the returning salmon were censused.For four experiments over 2 consecutive yr, the number of exposed and unexposed fish captured at the artificially scented stream were, 216 vs. 28, 437 vs. 49, 647 vs. 65, and 439 vs. 55. These differences were highly significant (P <.001).During the 3rd yr, morpholine was not added to the stream during the spawning migration and exposed and nonexposed fish returned in equal, low numbers (51 vs. 55, P >.05). These results confirm the existence of odor imprinting and long-term olfactory memory in coho salmon, It is possible that this mechanism is also used in the natural imprinting situation.

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Changes in run timing and natural smolt production in a naturally spawning coho salmon (Oncorhynchus kisutch) population after 60 years of intensive hatchery supplementation

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-119 ◽

2006 ◽

Vol 63 (10) ◽

pp. 2343-2355 ◽

Cited By ~ 46

Author(s):

Michael J Ford ◽

Howard Fuss ◽

Brant Boelts ◽

Eric LaHood ◽

Jeffrey Hard ◽

...

Keyword(s):

Natural Population ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Relative Fitness ◽

Stabilizing Selection ◽

Average Value ◽

Significant Difference ◽

Hatchery Supplementation ◽

Run Timing

Supplementing natural fish populations with artificially propagated (hatchery) fish is a common practice. In evaluating supplementation, it is important to assess the relative fitness of both hatchery-produced and naturally produced fish when they spawn together in the wild and to evaluate how the absolute fitness of the natural population changes after many generations of supplementation. We evaluated the relative fitness of naturally produced and hatchery-produced coho salmon (Oncorhynchus kisutch) in Minter Creek, Washington, USA. We also evaluated long-term changes in natural smolt production in this stream after several decades of intensive hatchery supplementation. Total smolt production was estimated to be 14 660 and 19 415 in 2002 and 2003, respectively, compared with the average value of 28 425 from 1940 to 1955. We found no significant difference in relative fitness between hatchery and natural fish, probably because the natural population consists largely of fish produced from the hatchery a generation or two previously. There has been a long-term trend for adults to return to the stream earlier in the spawning season. We estimated standardized selection differentials on run timing, with results indicating stabilizing selection with an optimum run timing later than the mean contemporary run timing but earlier than the historical mean run timing.

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Evaluation of a sustained-release polymer-encapsulated form of recombinant porcine somatotropin upon long-term growth performance of coho salmon, Oncorhynchus kisutch

Aquaculture ◽

10.1016/0044-8486(94)90344-1 ◽

1994 ◽

Vol 122 (4) ◽

pp. 359-368 ◽

Cited By ~ 12

Author(s):

Ewen McLean ◽

Edward M. Donaldson ◽

Ian Mayer ◽

Emin Teskeredzic ◽

Zlatica Teskeredzic ◽

...

Keyword(s):

Sustained Release ◽

Growth Performance ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Porcine Somatotropin

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Modification of Swimming Mode and Stamina in Two Stocks of Coho Salmon (Oncorhynchus kisutch) by Differing Levels of Long-Term Continuous Exercise

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-119 ◽

1983 ◽

Vol 40 (7) ◽

pp. 933-939 ◽

Cited By ~ 14

Author(s):

M. Besner ◽

L. S. Smith

Keyword(s):

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Water Velocity ◽

Moderate Exercise ◽

Control Groups ◽

Continuous Exercise ◽

Swimming Mode ◽

Critical Velocities

Coho salmon (Oncorhynchus kisutch) smolts from two different stocks were exercised continuously for 40 d at water velocities of 0.2 (control), 1.0, 1.5, and 2.0 body fork lengths per second. Their critical velocities and swimming characteristics were determined using a Blazka-type respirometer–stamina swimming chamber immediately after training and after 2 mo of rest. Endurance increased in exercised fish compared with control groups and the improvement was maintained after the period of rest. Swimming modes in freshwater differed between the two stocks, and it is suggested that these were adaptations resulting from differing genetical backgrounds. Continuous moderate exercise modified swimming modes in seawater. Long-term low water velocity regimes before release in the ocean might be a profitable rearing strategy for the survival of coho salmon because it allows an economy of energy during their oceanic migrations and improves their homeodynamic capacity.

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