The Effects of Starvation and Subsequent Feeding on Survival and Growth of Fulton Channel Sockeye Salmon Fry (Oncorhynchus nerka)

1973 ◽  
Vol 30 (1) ◽  
pp. 1-5 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
River Channel ◽  
Salmon Fry ◽  
Survival And Growth ◽  
Ad Libitum

In the laboratory 8 groups of Fulton River channel fry were starved for periods ranging from 1 to 7 weeks, then offered food ad libitum for 8 weeks. Fry withstood up to 4-weeks starvation with less than 10% mortality; beyond this point mortality increased sharply to 90% at 7-weeks starvation. At 5-weeks starvation both fry length and weight decreased significantly. Mortality continued when fish were offered food ad libitum after being starved. Among fish starved for 1 and 2 weeks, mortalities continued to be low, 0 and 6.6%, respectively; but, among fish starved from 3 to 5 weeks, mortalities rose considerably, ranging from 42 to 99%.

Effects of Starvation, Feeding, and Light Period on Circulus Formation on Scales of Young Sockeye Salmon (Oncorhynchus nerka)

1971 ◽  
Vol 28 (11) ◽  
pp. 1749-1755 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Light Period ◽  
Starvation Period ◽  
Scale Growth ◽  
Ad Libitum

Young sockeye salmon (Oncorhynchus nerka) survived a starvation period of 20 weeks with no change in their mean length and weight and with no record of this starvation period on their scales. Fish offered an ad libitum diet for more than 4 weeks in the 20-week period had significant increases in body and scale growth. The number of checks on their scales was correlated with the number of weeks fish were offered an ad libitum diet and not with the number of weeks they were starved. Thus, a significant increase in food induced the formation of a check. Light period appeared to have some influence on body and scale growth.

Daily Growth Rings in the Otoliths of Juvenile Sockeye Salmon (Oncorhynchus nerka)

1980 ◽  
Vol 37 (10) ◽  
pp. 1495-1498 ◽  
Author(s):  
K. H. Wilson ◽  
P. A. Larkin
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Growth Rings ◽  
Daily Growth ◽  
Salmon Fry

Sockeye salmon fry were collected from the Fulton River spawning channel at Babine Lake, British Columbia, in May 1978. The fish were reared for 26 d in enclosures in the spawning channel and were sampled every 7 to 10 d. The sagittae were removed from 25 fish from each sample, and the growth rings in one otolith from each fish were counted. A regression of the number of rings on the number of days since capture showed that these rings are, on average, formed daily, beginning at the time of emergence. A number of possible technical and biological causes of variation in ring counts within and between samples are considered.Key words: otolith, sagittae, daily growth rings, sockeye salmon fry

Quantifying cutthroat trout (Oncorhynchus clarki) predation on sockeye salmon (Oncorhynchus nerka) fry using a bioenergetics approach

1998 ◽  
Vol 55 (5) ◽  
pp. 1285-1295 ◽  
Author(s):  
Margaret A Cartwright ◽  
David A Beauchamp ◽  
Mason D Bryant
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Cutthroat Trout ◽  
Oncorhynchus Clarki ◽  
Field Sampling ◽  
Total Consumption ◽  
Model Simulations ◽  
Salmon Fry ◽  
Survey Results ◽  
Hydroacoustic Survey

Although some sockeye salmon (Oncorhynchus nerka) enhancement programs achieve production goals in Alaskan lakes, others like the Margaret Lake project fall well below expected levels. We used bioenergetics model simulations, coupled with field sampling of predator diet and distribution, to quantify the intensity of cutthroat trout (Oncorhynchus clarki) predation on stocked sockeye salmon fry in Margaret Lake during 1993 and 1994. Model results indicated that, by September, cutthroat trout consumed an estimated 34-51 and 32-100% of the 200 000 and 100 000 sockeye salmon fry stocked in May 1993 and 1994, respectively. September hydroacoustic survey results estimated a 82-87% decline of fry in 1993 and 90-93% in 1994. Stomach fullness and evacuation estimates of total consumption were 59% of model estimates after the first fry release in 1994 and 120% of the model estimates after the second release. All approaches to estimating cutthroat trout predation on stocked fry suggested that piscivores played a substantial role in the decline of sockeye salmon fry in Margaret Lake. The ability to estimate consumption is valuable in isolating predator influence on food web dynamics, especially in manipulated systems.

Behaviour and Ecology of Sockeye Salmon Fry in the Babine River

1967 ◽  
Vol 24 (2) ◽  
pp. 375-428 ◽  
Author(s):  
P. McCart
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Diel Pattern ◽  
Low Velocity ◽  
Migrant Populations ◽  
Salmon Fry

In the Upper and Lower Babine rivers the fry of sockeye salmon (Oncorhynchus nerka) emerge and move downstream, predominately at night, before reaching low-velocity areas along the stream margins. After a period of days or weeks these fry migrate upstream, close inshore, during the day. The diel pattern of upstream movement appears to be bimodal. The seasonal periodicities of both downstream and upstream movement are related to water temperatures.Upstream migrants were larger than downstream migrants in the Upper Babine River but not in the Lower Babine River. Upper River upstream migrants were similar in length to Lower River upstream migrants during 1964 but not in 1965. In both years Upper River fry weighed proportionately more than Lower River fry, and in both rivers 1964 fry weighed proportionately less than 1965 fry. Some possible explanations of these observations are discussed.Early in the season, fry tend to disperse alongshore after entering the lake. Later they leave these inshore areas and become entirely pelagic.The principal foods of fry both in the river and in the lake were copepod and cladoceran plankters.Both fish and birds were found to be preying on sockeye salmon fry. Fry appear to be more vulnerable to predation in the river than in the lake.The upstream movement of fry in the Babine River does not appear to differ appreciably from upstream movements in other areas. A comparison of fry movements in the Babine River and the Fulton River, where fry move only downstream, suggests that the differences in behaviour are genetically rather than environmentally induced.It is suggested that, because of high mortalities in the prepelagic period, upstream-migrant populations will only develop where the environment of both the river and the rearing lake are especially favourable.

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.

Transmission of Myxobolus arcticus Pugachev and Khokhlov, 1979, a myxosporean parasite of Pacific salmon, via a triactinomyxon from the aquatic oligochaete Stylodrilus heringianus (Lumbriculidae)

1993 ◽  
Vol 71 (6) ◽  
pp. 1207-1211 ◽  
Author(s):  
M. L. Kent ◽  
D. J. Whitaker ◽  
L. Margolis
Keyword(s):  
Life Cycle ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Well Water ◽  
Experimental Fish ◽  
Salmon Fry ◽  
Myxosporean Parasite ◽  
Transmission Studies ◽  
The Brain

Laboratory transmission studies were conducted on Myxobolus arcticus, a myxosporean that infects the brain of Pacific salmon (Oncorhynchus spp.). Attempts at transmission from fish to fish with spores of M. arcticus from sockeye salmon (Oncorhynchus nerka), including experiments with spores aged for up to 9 months in sterilized mud, were unsuccessful. Transmission was achieved when hatchery-reared (in well water) sockeye salmon fry were exposed to the oligochaete Stylodrilus heringianus collected from a lake where M. arcticus infections are common in this fish. All experimental fish exhibited the infection when examined 3 –4 months after exposure. Of 23 sockeye salmon fry exposed to triactinomyxon spores collected from naturally infected S. heringianus, 21 were found to be infected with M. arcticus spores when examined after 3 months. Thus, the life cycle of M. arcticus involves transformation into a triactinomyxon stage in S. heringianus. Alternate development of myxosporeans in aquatic oligochaetes has been established or implicated for nine other species of myxosporeans belonging to three families, but this is the first report of alternate development in a lumbriculid worm.

A Natural Epizootic of Infectious Hematopoietic Necrosis in Fry of Sockeye Salmon (Oncorhynchus nerka) at Chilko Lake, British Columbia

1976 ◽  
Vol 33 (7) ◽  
pp. 1564-1567 ◽  
Author(s):  
Ian V. Williams ◽  
Donald F. Amend
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Virus Disease ◽  
Oncorhynchus Nerka ◽  
Infectious Hematopoietic Necrosis Virus ◽  
Normal Range ◽  
Necrosis Virus ◽  
Natural Conditions ◽  
Salmon Fry ◽  
Infectious Hematopoietic Necrosis

The first confirmed epizootic of infectious hematopoietic necrosis virus disease under natural conditions is reported for sockeye salmon, Oncorhynchus nerka, in Chilko Lake, British Columbia. The outbreak occurred among fish of the 1972 brood during the spring of 1973. An estimated 825.6 million eggs were deposited in the Chilko River in 1972, and the production of 31.4 million fry that migrated into the lake in 1973 was significantly lower than the 55.1 million fry expected. The egg-to-fry survival of 3.8% was the lowest ever recorded at Chilko Lake (1949–73). The estimated fry-to-smolt survival of 57.1%, however, was well within the normal range for this lake. Apparently IHN severely reduced the survival of the 1972 brood of sockeye salmon fry at Chilko Lake, and all or nearly all of the reduction occurred during the egg-to-fry stage of the life cycle.

Effect of Temperature and Feeding Regime on the Specific Growth Rate of Sockeye Salmon Fry (Oncorhynchus nerka), with a Consideration of Size Effect

1973 ◽  
Vol 30 (8) ◽  
pp. 1191-1194 ◽  
Author(s):  
J. E. Shelbourn ◽  
J. R. Brett ◽  
S. Shirahata
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Sockeye Salmon ◽  
Specific Growth ◽  
Oncorhynchus Nerka ◽  
Effect Of Temperature ◽  
Salmon Fry ◽  
Wet Weight ◽  
Continuous Feeding ◽  
Specific Growth Rates

Specific growth rates were obtained for sockeye fry (Oncorhynchus nerka) acclimated to four temperatures and fed excess ration over a 36-day period, starting at an initial weight of 0.4 g. The rates were 2.2 (5 C), 5.1 (10 C), 6.5 (15 C), and 6.1 (20 C)% wet weight/day. Continuous feeding for 15 hr/day at 20 C produced a significantly greater growth rate than feeding to satiation three times daily (P < 0.05). The growth rates are compared to those obtained for larger sockeye, determined in earlier experiments.

Observations on the Migration of Sockeye Salmon Fry (Oncorhynchus nerka) in the Lower Babine River

1972 ◽  
Vol 29 (2) ◽  
pp. 151-159 ◽  
Author(s):  
W. Craig Clarke ◽  
H. D. Smith
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Behavioral Characteristics ◽  
Behavioral Differences ◽  
Spawning Grounds ◽  
Nursery Areas ◽  
Salmon Fry

No distinct length, weight, or behavioral differences associated with place of capture in the river were observed, indicating that all fry are susceptible to downstream displacement. A minimum of 7.5 million (18%) of the fry produced passed through a counting fence below the spawning grounds. Others reached quiet waters inshore, where they progressively developed behavioral characteristics that enabled them to ascend the river and reach lake nursery areas above. Two million fry ascended an improvised ladder spanning an area of turbulence at the base of the fence. Construction of leads and baffles at strategic places below the fence could help fry reach shore sooner and increase numbers reaching the lake.

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