Risk of predation and the feeding behavior of juvenile coho salmon (Oncorhynchus kisutch)

1984 ◽  
Vol 16 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Lawrence M. Dill ◽  
Alex H. G. Fraser
Keyword(s):  
Feeding Behavior ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Risk Of Predation

Physiological Response of Juvenile Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri) to Handling and Crowding Stress in Intensive Fish Culture

1976 ◽  
Vol 33 (12) ◽  
pp. 2699-2702 ◽  
Author(s):  
Gary A. Wedemeyer
Keyword(s):  
Rainbow Trout ◽  
Feeding Behavior ◽  
Coho Salmon ◽  
Physiological Stress ◽  
Oncorhynchus Kisutch ◽  
Fish Distribution ◽  
Salmo Gairdneri ◽  
Crowding Stress ◽  
Normal Feeding ◽  
Intensive Fish Culture

Moving 4–5-in. coho salmon (Oncorhynchus kisutch) held in soft (20 ppm CaCO3) water from the relatively light loading density of 0.5 lb/ft3 to 1, 2, or 4 lb/ft3 (density index, DI = 0.1, 0.2, 0.4, 0.8) caused significant stress as indicated by loss of feeding behavior, but only minimal physiological disturbances, as indicated by lack of hyperglycemia or hypochloremia. However, moving them to 6 or 12 lb/ft3 (DI = 1.2, 2.4) caused significant physiological stress which required at least a week for recovery. Smolting coho salmon were physiologically stressed by population densities of 1 lb/ft3 or more and a subclinical corynebacterial kidney infection was activated. Rainbow trout (Salmo gairdneri) (4–5 in.) were physiologically stressed when moved and held at 1 lb/ft3 or more but retained normal feeding behavior. This indicates that handling and crowding stress will be minimized in softwater areas if densities in fish distribution trucks or in ponds or raceways during disease treatments are held to 0.1–0.5 lb/gal.

Changes in Territorial, Gill-flaring, and Feeding Behavior in Juvenile Coho Salmon (Oncorhynchus kisutch) following Short-term Pulses of Suspended Sediment

1985 ◽  
Vol 42 (8) ◽  
pp. 1410-1417 ◽  
Author(s):  
L. Berg ◽  
T. G. Northcote
Keyword(s):  
Feeding Behavior ◽  
Suspended Sediment ◽  
Brine Shrimp ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Turbid Water ◽  
Short Term ◽  
Dominance Hierarchies ◽  
Short Term Exposure ◽  
Laboratory Stream

The territorial, gill-flaring, and feeding behavior of juvenile coho salmon (Oncorhynchus kisutch) in a laboratory stream was disrupted by short-term exposure to suspended sediment pulses. At the higher turbidities tested (30 and 60 nephelometric turbidity units (NTU)), dominance hierarchies broke down, territories were not defended, and gill flaring occurred more frequently. Only after return to lower turbidities (0–20 NTU) was social organization reestablished. The reaction distance of the fish to adult brine shrimp decreased significantly in turbid water (30 and 60 NTU) as did capture success per strike and the percentage of prey ingested. Implications of these behavioral modifications suggest that the fitness of salmonid populations exposed to short-term pulses of suspended sediment may be impaired.

Adaptive Flexibility in the Foraging Behavior of Fishes

1983 ◽  
Vol 40 (4) ◽  
pp. 398-408 ◽  
Author(s):  
Lawrence M. Dill
Keyword(s):  
Feeding Behavior ◽  
Foraging Behavior ◽  
Food Availability ◽  
Graphical Model ◽  
Coho Salmon ◽  
Behavioral Flexibility ◽  
Rate Of Change ◽  
Natural Environments ◽  
Feeding Rates ◽  
Risk Of Predation

Flexibility is an important adaptive feature of the foraging behavior of fishes, because most natural environments vary both spatially and temporally. Fish should respond to low levels of food availability by altering their behavior in ways which ensure higher feeding rates, larger feeding territories, and broader diets. It is shown that the gastric sensation of hunger and its rate of change may act as appropriate cues to food availability, and observed hunger-motivated changes in feeding behavior can produce all of these predicted effects. Data are presented to show that juvenile coho salmon (Oncorhynchus kisutch) alter their behavior in an adaptive manner when faced with variable degrees of threat of competition from territorial intruders, and of risk of predation. A review of similar studies on other species supports the generality of these results. Learning is an important mechanism providing behavioral flexibility, and changes in fish feeding behavior with experience are summarized. A graphical model is developed to show that these changes can result in training biases and food specialization. Learning also results in increased feeding rates. The consequences of these observations for the development of refined models of foraging are discussed.

Induced ovulation in coho salmon (Oncorhynchus kisutch). I. Further studies on the use of salmon pituitary preparations

Aquaculture ◽  
1981 ◽  
Vol 26 (1-2) ◽  
pp. 117-127 ◽  
Author(s):  
George A. Hunter ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Induced Ovulation

scholarly journals Hyperbilirubinemia of Coho Salmon Oncorhynchus kisutch Infected with Erythrocytic Inclusion Body Syndrome (EIBS) Virus

1994 ◽  
Vol 60 (5) ◽  
pp. 519-521 ◽  
Author(s):  
Tadashi Sakai ◽  
Hisashi Murata ◽  
Kiyoshi Yamauchi ◽  
Kiyotaka Takahashi ◽  
Nobuaki Okamoto ◽  
...  
Keyword(s):  
Inclusion Body ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch
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