Molybdenum Concentrations in Tissues of Rainbow Trout (Salmo gairdneri) and Kokanee Salmon (Oncorhynchus nerka) from Waters Differing Widely in Molybdenum Content

1973 ◽  
Vol 30 (6) ◽  
pp. 841-842 ◽  
Author(s):  
James V. Ward
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Weight Basis ◽  
Molybdenum Content ◽  
Salmo Gairdneri ◽  
Kokanee Salmon ◽  
Water Fish ◽  
Wet Weight ◽  
Molybdenum Concentration

Concentrations of molybdenum in tissues of rainbow trout (Salmo gairdneri) from three waters increased only slightly with increase in molybdenum concentration of the water. Fish from high (300 ppb) molybdenum water had mean concentrations of 13–332 ppb on a wet-weight basis; those from low (6 ppb) molybdenum water, 10–146 ppb; and those from trace molybdenum water, 5–118 ppb. Rainbow trout exhibited generally higher molybdenum concentrations than did kokanee salmon (Oncorhynchus nerka) in high molybdenum water. A possible plateau mechanism concerning molybdenum accumulation by salmonids is discussed.

The life histories and trophic relationships of the Trichoptera of Marion Lake, British Columbia

1971 ◽  
Vol 49 (5) ◽  
pp. 623-635 ◽  
Author(s):  
Michael J. Winterbourn
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Life Histories ◽  
Oncorhynchus Nerka ◽  
Trophic Relationships ◽  
Salmo Gairdneri ◽  
Taricha Granulosa ◽  
Kokanee Salmon ◽  
Competitive Species ◽  
Species Being

Life histories and trophic relationships of Trichoptera were studied in a small British Columbia lake. Larvae of 10 caddis species were primarily sediment feeders, 2 were leaf feeders, 3 carnivores, and 1 Banksiola crotchi, an algal feeder in early instars and predaceous in later ones. The final instar larvae of potentially competitive species tended to be separated in time. Caddis larvae were an important component of the diet of rainbow trout (Salmo gairdneri), species being preyed upon sequentially as their later instars appeared in the lake. Larvae were also important as prey of the salamander Taricha granulosa but were less significant in the diets of kokanee salmon (Oncorhynchus nerka) and a second salamander Ambystoma gracile.

Role of gravel substrate on ova survival and alevin emergence of rainbow trout, Salmo gairdneri

1981 ◽  
Vol 59 (4) ◽  
pp. 629-636 ◽  
Author(s):  
Larry D. Witzel ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Incubation Temperature ◽  
Salmo Gairdneri ◽  
Void Space ◽  
Poor Survival ◽  
Percent Survival ◽  
Gravel Size ◽  
Wet Weight ◽  
Developmental Condition

The role of gravel size of unigranular diameters 2, 4, 8, 16, and 26.5 mm on ova survival and subsequent emergence of rainbow trout alevins is examined using a vertical-flow incubation apparatus. Survival to emergence, time of emergence, and alevin condition at emergence were signficantly influenced [Formula: see text] by gravel size. Mean percent survival to emergence increased with gravel size from a minimum of 1% in the 2-mm gravel to a maximum of 76% in the 26.5-mm gravel. Survival of control ova from gravel-free incubator was 88% to swim-up stage. Differences in percent survival were most significant within the 2 to 8 mm range. Poor survival of trout alevins in the finer gravels (2–4 mm) was the result of insufficient void space (entrapment). Days to first (43–58 days after ova burial) and 50% emergence (49–62 days after ova burial) also increased with gravel size. At a mean incubation temperature of 10.6 °C, the total emergence days was greatest (40 days) from the 8-mm gravel and occurred prematurely on day 37 after ova burial in 2-mm gravel. Alevin length and weight varied directly with gravel size, ranging from 2.17 to 2.39 cm and 11.9 to 126.8 mg, respectively. Larger alevins, which emerged later from coarser gravels had the least yolk reserve [Formula: see text] and the lowest KD values [Formula: see text], where KD is a developmental condition factor calculated from the ratio of wet weight to standard length. Premature emergence of free embryos and shortening of the alevin îmergence period in 2.0-mm gravel is identified as a stress response.

Factors Affecting Rainbow Trout (Salmo gairdneri) Predation on Migrant Fry of Sockeye Salmon (Oncorhynchus nerka)

1976 ◽  
Vol 33 (1) ◽  
pp. 19-24 ◽  
Author(s):  
R. M. Ginetz ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Development Stage ◽  
Salmo Gairdneri ◽  
Factors Affecting ◽  
Light Intensities ◽  
Salmon Fry ◽  
Lower Stream ◽  
Downstream Movement

Predation of rainbow trout (Salmo gairdneri) on migrant sockeye salmon (Oncorhynchus nerka) fry in experimental streams was higher on fry at an earlier development stage, in moonlight by contrast to cloudy night light intensities, at lesser turbidities, and at lower stream velocities. At dusk light intensities, from.05 to.30 ft-c, mortality from predation was inversely related to light intensity. The longer the period of exposure of fry to naturally declining light intensities prior to downstream movement, the lower was the loss to predators. Exposure of predators to high light intensities prior to the downstream movement of fry resulted in decreased fry mortality. Fry that had survived exposure to predators in an experimental stream 1 and 2 days previous were less vulnerable to predation than "naive" fry. Successive exposures further decreased the loss to predation. Fry enumerated at a counting fence suffered less predation than fry not enumerated. Experienced fry moved downstream more rapidly than naive fry.In laboratory aquaria, experienced fry formed compact schools prior to and in response to stimuli, while naive fry formed loose schools or did not school. Experienced fry were less active in responding to stimuli. Enumerated fry resembled experienced fry; nonenumerated fry resembled naive fry.Various techniques of enhancing sockeye salmon fry survival during downstream migration are suggested by these results.

Effect of Metopirone on Pituitary–Interrenal Function in Two Teleosts, Sockeye Salmon (Oncorhynchus nerka) and Rainbow Trout (Salmo gairdneri)

1968 ◽  
Vol 25 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Ulf H. M. Fagerlund ◽  
J. R. McBride ◽  
Edward M. Donaldson
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Inhibitory Effect ◽  
Salmo Gairdneri ◽  
Pars Distalis ◽  
Marked Inhibitory Effect ◽  
Interrenal Cells ◽  
Rostral Region ◽  
Low Dosage

Metopirone (SU 4885), an inhibitor of 11β-hydroxylation of adrenocorticosteroids, was administered intramuscularly to adult castrated sockeye salmon (Oncorhynchus nerka) and intact rainbow trout (Salmo gairdneri). Marked hypertrophy of interrenal cells pointed to an increase in the activity of the interrenal tissue of both species. Increased cortisol concentrations in trout at low dosage levels of metopirone suggested that the drug was stressful. However, decreased concentrations at higher dosage levels in trout, and decreased cortisol concentrations in all salmon indicated that the drug was also exerting a marked inhibitory effect on 11β-hydroxylation. In salmon, a repository ACTH preparation (acthar) brought about interrenal hypertrophy similar to that produced by metopirone. Metopirone also induced degranulation and hyperplasia of the cells of the palisade-like layer in the rostral region of the pars distalis in both species of fish. These cells were the only cell type of the pars distalis that were stained with lead-haematoxylin. The evidence indicates that they are the corticotrops.

Report of the metacestode of Paradilepis simoni Rausch, 1949 (Cyclophyllidea: Dilepidae) from fish in British Columbia

1982 ◽  
Vol 60 (2) ◽  
pp. 184-186 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Size And Shape ◽  
Larval Stages ◽  
Prosopium Williamsoni

Larval stages of tapeworms were found encysted in the livers of the following fish: 77% of 87 Oncorhynchus nerka (Walbaum), kokanee; 22% of 111 Salmo gairdneri (Richardson), rainbow trout; 13% of 113 Ptychocheilus oregonensis (Richardson), northern squawfish; 3% of 98 Prosopium williamsoni (Girard), mountain whitefish; and 2% of 85 Cottus asper (Richardson), prickly sculpin. The metacestodes were identified to be that of Paradilepis simoni from the number, size, and shape of the rostellar hooks.

Electrical Responses of the Olfactory Bulb of Pacific Salmon Oncorhynchus nerka and Oncorhynchus kisutch

1972 ◽  
Vol 29 (9) ◽  
pp. 1351-1355 ◽  
Author(s):  
Toshiaki J. Hara
Keyword(s):  
Rainbow Trout ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Threshold Concentration ◽  
Salmo Gairdneri ◽  
Olfactory Responses ◽  
Amino Acid Solutions ◽  
Normal Fish ◽  
Different Sources ◽  
Electrical Responses

Olfactory bulbar electrical responses elicited by nasal infusion of food extracts, hand rinse, and several amino acid solutions were studied in sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon from several different sources. Comparison was also made in rainbow trout (Salmo gairdneri). Significant variations in the olfactory bulbar responses were observed among different species and even among the same species from different sources. The estimated lowest threshold concentration for L-serine was between 10−6 and 10−7 M in salmon. Olfactory responses of rainbow trout were always several times larger than those of salmon.Pretreatment of nasal cavity with 10−4 M solutions of HgCl2 or CuSO4 (27 or 16 mg/liter, respectively) for 10 sec completely blocked the olfactory responses in all fish species studied. The effect was reversible; the responses returned to their original level by rinsing. Exposure of fish to 0.1 mg/liter HgCl2 for up to 3 days reduced the olfactory responses to 40–10% of those of normal fish. CuSO4 was the more toxic.

Sublethal Toxicity of Cyanide to Rainbow Trout (Salmo gairdneri) at Different Temperatures

1982 ◽  
Vol 39 (10) ◽  
pp. 1389-1395 ◽  
Author(s):  
Tibor G. Kovacs ◽  
Gérard Leduc
Keyword(s):  
Rainbow Trout ◽  
Growth Rates ◽  
Swimming Performance ◽  
Dry Weight ◽  
Liver Glycogen ◽  
Salmo Gairdneri ◽  
Sublethal Toxicity ◽  
Different Temperatures ◽  
Wet Weight ◽  
Flow Through

At sublethal levels cyanide was more potent at lower temperatures. This was verified in 20-d laboratory growth experiments carried out on juvenile rainbow trout (Salmo gairdneri) in flow-through aquaria maintained at 6, 12, and 18 °C. Cyanide concentrations in the range of 0.005–0.045 mg∙L−1 HCN significantly reduced growth rates (wet weight, dry weight, and fat), the effective concentrations increasing with temperature. Some adaptation to cyanide seemed to occur as manifested by faster growth rates. Liver glycogen and lactic acid monitored for 20 d in rainbow trout exposed to 0.015 mg∙L−1 HCN showed an initial shift towards glycolysis, followed by a return to aerobic respiration. This response, however, varied with temperatures. Previous exposure to cyanide markedly reduced swimming performance of the fish tested at their acclimation temperatures, but in the absence of the toxicant. The effect also increased with decreasing temperatures.Key words: cyanide, sublethal toxicity, rainbow trout, temperature, growth, swimming, liver metabolites

Sign in / Sign up

Export Citation Format

Share Document