Experimental Confirmation of the Olfactory Hypothesis with Homing, Artificially Imprinted Coho Salmon (Oncorhynchus kisutch)

1976 ◽  
Vol 33 (4) ◽  
pp. 703-710 ◽  
Author(s):  
Jon C. Cooper ◽  
Allan T. Scholz ◽  
Ross M. Horrall ◽  
Arthur D. Hasler ◽  
Dale M. Madison
Keyword(s):  
Lake Michigan ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Spawning Migration ◽  
Experimental Confirmation ◽  
Olfactory Memory ◽  
Paired Group ◽  
Low Concentrations

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.

Electrophysiological Studies of Morpholine-Imprinted Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri)

1976 ◽  
Vol 33 (4) ◽  
pp. 688-694 ◽  
Author(s):  
Jon C. Cooper ◽  
Arthur D. Hasler
Keyword(s):  
Rainbow Trout ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Control Fish ◽  
Salmo Gairdneri ◽  
Paired Group ◽  
Naturally Occurring ◽  
Data Support ◽  
Electrophysiological Studies

Two groups of coho salmon (Oncorhynchus kisutch) were exposed to a 5 × 10−5 mg/liter concentration of a synthetic chemical, morpholine, for 4 wk during the smolting period, while two corresponding groups were left unexposed (controls). All groups were marked by finclipping and stocked into Lake Michigan near the mouth of Oak Creek (South Milwaukee, Wisconsin). A second series of exposed and unexposed salmon was released 13 km north of Oak Creek. Rainbow trout (Salmo gairdneri) were tested in a similar experiment.Homing salmonids were censused and then used in physiological experiments. Electroencephalographic studies showed significantly greater responses by the experimental (exposed) compared to control fish to 1% morpholine (P ≤ 0.001 − 0.05) and by one paired group to a stream sample scented with morpholine (about 10−3 mg/liter morpholine P ≤ 0.01). Responses to morpholine were specific in that another chemical similar to it did not elicit responses. These data support the olfactory hypothesis that salmon may imprint to naturally occurring homestream odors in the same way as they do to morpholine.

Fecundity of Coho Salmon (Oncorhynchus kisutch) from the Great Lakes and a Comparison with Ocean Salmon

1976 ◽  
Vol 33 (5) ◽  
pp. 1150-1155 ◽  
Author(s):  
Thomas M. Stauffer
Keyword(s):  
Great Lakes ◽  
Early Life ◽  
First Generation ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Lake Superior ◽  
Oncorhynchus Kisutch ◽  
Early Life History ◽  
Freshwater Salmon

I measured fecundity of coho salmon (Oncorhynchus kisutch) that matured in the Great Lakes to make comparisons with Pacific Ocean coho salmon and among groups of Great Lakes salmon. Numbers of eggs produced (1600–3500) by Great Lakes salmon were comparable to production (1500–3300) by Pacific salmon of similar size. Average egg diameters of Lake Michigan (7.1–7.4 mm) and Pacific salmon (6.1–7.4 mm) were also comparable but Lake Superior eggs were smaller (5.1–5.4 mm). Fecundity of second generation freshwater salmon which originated from Lake Michigan eggs was similar to that of the first generation which originated from Pacific eggs because the average numbers (2938–3243) and diameters (7.1–7.4 mm) of eggs produced were about the same. On the average, Lake Michigan salmon contained more (2938) and larger (7.1-mm diam) eggs than did Lake Superior salmon (2150 and 5.1-mm diam) of the same year-class and early life history.

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

2000 ◽  
Vol 118 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Dianne M. Baker ◽  
Donald A. Larsen ◽  
Penny Swanson ◽  
Walton W. Dickhoff
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Physiologic Effect

Endohelminths of salmonids from two localities in eastern Lake Michigan, with emphasis on Echinorhynchus salmonis

1989 ◽  
Vol 67 (6) ◽  
pp. 1604-1607 ◽  
Author(s):  
Patrick M. Muzzall
Keyword(s):  
Chinook Salmon ◽  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salvelinus Namaycush ◽  
Salmo Gairdneri ◽  
Brown Trout Salmo Trutta

Adult salmonids (101 chinook salmon, Oncorhynchus tshawytscha; 7 coho salmon, Oncorhynchus kisutch; 56 lake trout, Salvelinus namaycush; 6 steelhead, Salmo gairdneri; and 2 brown trout, Salmo trutta) were collected from eastern Lake Michigan (Ludington and Manistee, Michigan) in July–September 1986, and examined for helminths. Eight species (three Cestoda, three Nematoda, two Acanthocephala) were found in the digestive tract and other viscera. Echinorhynchus salmonis and Eubothrium salvelini were the most common helminths found. The intensity of E. salmonis significantly increased as chinook salmon became older and longer.

Comparative fecundity and egg survival of coho salmon (Oncorhynchus kisutch Walbaum) from lakes Ontario, Erie, and Michigan

1985 ◽  
Vol 63 (5) ◽  
pp. 1096-1100 ◽  
Author(s):  
P. F. Morrison ◽  
J. F. Leatherland ◽  
R. A. Sonstegard
Keyword(s):  
New York ◽  
Lake Erie ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Lake Ontario ◽  
Viral Disease ◽  
Fertilization Success ◽  
Egg Survival ◽  
Salmon River

Survival to hatch in 1982 of coho salmon (Oncorhynchus kisutch Walbaum) collected from two Lake Ontario stocks (Salmon River, New York, and Credit River, Ontario) and Lake Michigan and Lake Erie stocks in 1982 was 79, 86, 78 and 24%, respectively; eggs taken from smaller females (<2 kg) of the Lake Erie stock had a significantly lower survival (9%) than those of larger females (>2 kg). Poor fertilization success appeared to be the major cause of low survival to hatch of Lake Erie coho salmon eggs. There were no significant differences in egg size, embryo size, or development time to hatch, step E47, or first exogenous feeding in the four stocks studied, although the incidence of alevin deformity was significantly higher in the Lake Erie coho salmon than in the Lake Ontario or Lake Michigan stocks. Posthatch mortalities were low, except in the case of the Credit River (Lake Ontario) stock, which suffered an epizootic of a suspect viral disease that increased mortality 3 weeks after hatch.

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