Precocious Sexual Development in Hatchery-Reared and Laboratory-Maintained Male Steelhead Trout (Salmo gairdneri)

The incidence of precocious steelhead trout (Salmo gairdneri) was determined in several Idaho hatchery steelhead populations. The range of incidence of precocious males was 0–64% of the sampled populations. This variation appeared to be related to age of the trout, water temperature, and photoperiod. The incidence of precocious males greatly exceeded the incidence (0.1% of the population when encountered) of precocious females. Precocious male steelhead trout are apparently lost from the migrating smolt population and display mating behavior similar to sea-run adult male steelhead. Precocious males maintained in laboratory conditions remained sexually mature for at least 6 mo of observation. This was reflected by mean gonadal weights and mean gonadosomatic indices from precocious male steelhead which differed significantly from nonprecocious juvenile male steelhead maintained under similar conditions. No consistent pattern of growth was observed among laboratory-maintained trout. Key words: steelhead trout, reproduction, precocious sexual maturation, age, photoperiod, temperature

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Swimming Stamina Differences Between Genotypically Distinct Forms of Rainbow (Salmo gairdneri) and Steelhead Trout

Journal of the Fisheries Research Board of Canada ◽

10.1139/f77-152 ◽

1977 ◽

Vol 34 (7) ◽

pp. 996-1003 ◽

Cited By ~ 28

Author(s):

H. Tsuyuki ◽

S. N. Williscroft

Keyword(s):

Rainbow Trout ◽

Lactate Dehydrogenase ◽

Key Words ◽

Low Frequency ◽

Water Velocity ◽

Salmo Gairdneri ◽

Steelhead Trout ◽

Very Low Frequency ◽

Time Required

Rainbow trout (Salmo gairdneri) homozygous for liver lactate dehydrogenase alleles ldhHαA and ldhHαB were artificially propagated and their swimming stamina compared. The time required to fatigue 50% of the HαAHαA phenotypes in fixed water velocity tests was 2.3 times greater on the average than that of HαAHαB phenotypes.Likewise, LDH phenotypes HαAHαA, HαAHαB, and HαAHαB of steelhead trout from the Thompson River were artifically propagated and their swimming stamina compared. In contrast to the rainbow trout, significant differences in stamina among the three phenotypes of steelhead were not evident in the stocks from this river nor between phenotypes HαAHαB and HαBHαB from another stream, the Vedder River, which has a very low frequency of the ldhHαA allele. The stamina of young steelhead from the Thompson River was, however, 3.8 times greater than that of those from the Vedder River. Key words: stamina, LDH, rainbow trout, steelhead, phenotype, swimming, fatigue

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Survival of Steelhead Trout (Salmo gairdneri) Eggs, Embryos, and Fry in Air-Supersaturated Water

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-043 ◽

1978 ◽

Vol 35 (2) ◽

pp. 261-264 ◽

Cited By ~ 18

Author(s):

Alan V. Nebeker ◽

James D. Andros ◽

Joel K. McCrady ◽

Donald G. Stevens

Keyword(s):

Key Words ◽

Yolk Sac ◽

Fish Culture ◽

Salmo Gairdneri ◽

Gas Bubble ◽

Life Stages ◽

Steelhead Trout ◽

Gas Saturation ◽

Gas Bubble Disease ◽

Gill Cavity

Egg, embryo, fry, and swim-up stages of steelhead trout (Salmo gairdneri) were exposed to water at total gas saturation levels ranging from 130 to 115%. Eggs, embryos, and newly hatched fry were not affected at 126.7%, but at about day 16 posthatch when the fish began swimming up deaths occurred rapidly, and at the end of the test post button-up mortality ranged from 99% at 126.7% saturation to 45% at 115.3% saturation. Bubbles in the mouth, gill cavity, and yolk sac caused flotation and severe respiratory difficulties. Rupture of yolk-sac membranes also caused death. No differences were noted in survival between fish exposed from egg to fry, and those exposed only from swim-up to fry stage. In summary, there were differences in susceptibility among steelhead life stages to air-supersaturated water; eggs, embryos, and pre-swim-up larvae were more resistant than swim-up and later fry stages. Key words: trout, steelhead, supersaturation, gas-bubble disease, Salmo gairdneri, temperature, fish culture

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Relation of Water Temperature to Flexibacter columnaris Infection in Steelhead Trout (Salmo gairdneri), Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon

Journal of the Fisheries Research Board of Canada ◽

10.1139/f75-182 ◽

1975 ◽

Vol 32 (9) ◽

pp. 1553-1559 ◽

Cited By ~ 44

Author(s):

R. A. Holt ◽

J. E. Sanders ◽

J. L. Zinn ◽

J. L. Fryer ◽

K. S. Pilcher

Keyword(s):

Water Temperature ◽

Experimental Infection ◽

Chinook Salmon ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Disease Process ◽

Salmo Gairdneri ◽

Contact Method ◽

Steelhead Trout ◽

Time To Death

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.

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Coronary degeneration in sexually mature rainbow and steelhead trout, Salmo Gairdneri

Atherosclerosis ◽

10.1016/0021-9150(78)90171-5 ◽

1978 ◽

Vol 29 (4) ◽

pp. 431-437 ◽

Cited By ~ 29

Author(s):

Jack E. McKenzie ◽

Edwin W. House ◽

James G. McWilliam ◽

Donald W. Johnson

Keyword(s):

Salmo Gairdneri ◽

Steelhead Trout ◽

Sexually Mature

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Interactions Between the Redside Shiner (Richardsonius balteatus) and the Steelhead Trout (Salmo gairdneri) in Western Oregon: The Influence of Water Temperature

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-194 ◽

1987 ◽

Vol 44 (9) ◽

pp. 1603-1613 ◽

Cited By ~ 51

Author(s):

Gordon H. Reeves ◽

Fred H. Everest ◽

James D. Hall

Keyword(s):

Water Temperature ◽

Warm Water ◽

Salmo Gairdneri ◽

Intermediate Water ◽

Steelhead Trout ◽

Cool Water ◽

Influence Of Water ◽

Similar Range ◽

Redside Shiner ◽

Richardsonius Balteatus

Water temperature influenced interactions between redside shiner (Richardsonius balteatus) and juvenile steelhead trout (Salmo gairdneri) (≥1 +) in the field and laboratory. Trout in cool water when shiner were absent and at intermediate water temperatures with shiner present occupied a similar range of habitats. Shiner alone in warm water occupied habitats similar to trout, but in the presence of trout occupied slower, deeper areas than when alone. In laboratory streams, production by trout was the same in the presence and absence of shiner in cool water (12–15 °C). In warm water (19–22 °C), production by trout decreased by 54% in the presence of shiner compared with when shiner were absent. Production of shiner in cool water decreased in the presence of trout, −0.3 g∙m−2∙d−1 together compared with 0.5 g∙m−2∙d−1 alone, but was not affected by the presence of trout in warm water. Trout distribution was not influenced by shiner in cool waters, but was influenced at warm temperatures. Shiner occupied all areas of the laboratory channels in the absence of trout in cool waters but were restricted to a few pools in the presence of trout. Distribution of shiner was not influenced by trout at warm temperatures.

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Aspects of the Winter Ecology of Juvenile Coho Salmon (Oncorhynchus kisutch) and Steelhead Trout (Salmo gairdneri)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f75-086 ◽

1975 ◽

Vol 32 (5) ◽

pp. 667-680 ◽

Cited By ~ 148

Author(s):

David R. Bustard ◽

David W. Narver

Keyword(s):

Water Temperature ◽

Coho Salmon ◽

Age Groups ◽

Oncorhynchus Kisutch ◽

Salmo Gairdneri ◽

Steelhead Trout ◽

Tree Roots ◽

Beaver Ponds ◽

Stream System ◽

Overwintering Area

The major physical characteristics of overwintering areas for juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri) are described for a small, unlogged, west coast Vancouver Island stream. During the winter months age I+ coho and steelhead were found at a range of depths mainly greater than 45 cm and in deeper water than age 0 of either species. About 45% of age 0 steelhead observed were in water < 15 cm deep. The depth occupied by coho and age I+ steelhead was negatively correlated with water temperature below 8.5 C. Coho were associated less closely with the bottom than were steelhead. At 7 C or less most fish were associated with water velocities of < 15 cm/s. Velocities in which steelhead occurred were positively correlated with rising temperature above 4 C. As water temperature decreased from 9 to 2 C, coho and steelhead moved closer to cover. Cover used by coho and age I+ steelhead most frequently was logs and upturned tree roots, although debris accumulations and overhanging banks were also used. Both age-groups of coho used overhanging brush but steelhead did not. Over 50% of age 0 steelhead were associated with rocks 10–25 cm in diameter. Sidepools and quiet back channels that contained water only in the winter and that had combinations of the above cover types were populated by coho during the winter. A series of unused beaver ponds, dry in the summer, was an important overwintering area for coho with a survival rate about twice as high as the 35% estimated for the entire stream system.

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Relation of Water Temperature to Infections of Coho Salmon (Oncorhynchus kisutch), Chinook Salmon (O. tshawytscha), and Steelhead Trout (Salmo gairdneri) with Aeromonas salmonicida and A. hydrophila

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-001 ◽

1978 ◽

Vol 35 (1) ◽

pp. 1-7 ◽

Cited By ~ 35

Author(s):

W. J. Groberg Jr. ◽

R. H. McCoy ◽

K. S. Pilcher ◽

J. L. Fryer

Keyword(s):

Water Temperature ◽

Chinook Salmon ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Infected Fish ◽

Aeromonas Salmonicida ◽

Salmo Gairdneri ◽

Steelhead Trout

Juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (O. tshawytscha) were infected by intraperitoneal or intramuscular injection with Aeromonas salmonicida or A. hydrophila at seven temperatures from 3.9 to 20.5 °C. At 3.9 and 6.7 °C, mortality in fish infected with A. salmonicida varied from 2 to 26% among the three salmonid species. At 20.5 °C 93–100% of these animals died within 2 or 3 days; at 6.7 °C or lower the fish survived for 12–23 days. Growth of A. salmonicida in vitro was influenced by temperature in a manner very similar to its influence on the in vivo infection. Comparable experiments with A. hydrophila gave results much like those with A. salmonicida, though some differences were noted. At a temperature of 20.5 °C percent mortality ranged from 64 to 100%. At 9.4 °C or below no deaths attributed to A. hydrophila occurred. Fatally infected fish died more rapidly at the higher temperatures. Key words: Aeromonas salmonicida, A. hydrophila, water temperature, furunculosis, motile aeromonas septicemia, coho salmon, chinook salmon, steelhead trout

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The regulation of day–night changes in hydroxyindole-O-methyltransferase activity in the pineal gland of steelhead trout (Salmo gairdneri)

Canadian Journal of Zoology ◽

10.1139/z76-175 ◽

1976 ◽

Vol 54 (9) ◽

pp. 1530-1534 ◽

Cited By ~ 30

Author(s):

John R. Smith ◽

Lavern J. Weber

Keyword(s):

Pineal Gland ◽

Sharp Increase ◽

Pineal Region ◽

Salmo Gairdneri ◽

Steelhead Trout ◽

Methyltransferase Activity ◽

Surgical Exposure

Elevation in pineal hydroxyindole-O-methyltransferase (HIOMT; EC 2.1.1.4) activity in juvenile steelhead trout was associated with the dark portions of three different photoperiods with a sharp increase in pineal HIOMT activity occurring in the first 4 h of darkness. This pattern of activity could be abolished by bilateral enucleation but not by surgical capping of the pineal region. Surgical exposure of the pineal region in blinded fish did not restore HIOMT responses to changes in lighting.

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