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

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.

1976 ◽  
Vol 33 (12) ◽  
pp. 2699-2702 ◽  
Author(s):  
Gary A. Wedemeyer

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.


1981 ◽  
Vol 38 (7) ◽  
pp. 772-778 ◽  
Author(s):  
Desmond J. Maynard ◽  
Douglas D. Weber

Presmolt coho salmon (Oncorhynchus kisutch) tested in a Y-maze avoided a mixture of monocyclic aromatic hydrocarbons at concentrations of 3–4 mg/L while smolting coho salmon avoided concentrations of less than 2 mg/L. Three components (benzene, toluene, o-xylene) of the mixture were tested individually with presmolt salmon and each was avoided at a lower concentration than when compared with the total hydrocarbon concentration of the mixture; o-xylene was most repellent, causing statistically significant avoidance at a concentration of 0.2 mg/L. Electrophysiological recordings from the olfactory bulb indicated that short-term exposure of juvenile coho salmon to monocyclic aromatic hydrocarbons at 4 mg/L did not disrupt this chemosensory modality; the olfactory system was stimulated by an aromatic hydrocarbon mixture at concentrations correlating with observed avoidance behavior.Key words: salmon, behavior, avoidance, monocyclic aromatic hydrocarbons, Oncorhynchus, olfactory EEG


1989 ◽  
Vol 46 (8) ◽  
pp. 1383-1391 ◽  
Author(s):  
John F. Thedinga ◽  
Michael L. Murphy ◽  
Jonathan Heifetz ◽  
K V. Koski ◽  
Scott W. Johnson

Short-term effects of logging on age composition and size of juvenile coho salmon (Oncorhynchus kisutch) were studied in 18 streams in Southeast Alaska in 1982 and 1983; studies were in old-growth and clear-cut reaches with or without buffer strips. The number of fry (age 0) in summer and winter was proportionately higher in buffered and clear-cut reaches than in old-growth reaches, and all treatments averaged a 20% decrease in fry from summer to winter. Fry length and condition factor were greater for buffered and clear-cut reaches than for old-growth reaches, whereas parr (age 1 and older) size did not differ among treatments. Fry and parr were larger in the southern than in the northern regions and their length and weight were directly related to peripbyton biomass and benthos density. A higher percentage of large [Formula: see text] fry remained in buffered reaches than in clear-cut and old-growth reaches; therefore, the density of fry that were potentially large enough to become smolts the next spring (presmolts) was greater in buffered reaches. The larger fry in buffered and clear-cut reaches compared with old-growth reaches was probably due to earlier fry emergence that resulted from increased water temperature.


Cryobiology ◽  
2020 ◽  
Vol 95 ◽  
pp. 44-50 ◽  
Author(s):  
Osvaldo Merino ◽  
Kelly Dumorné ◽  
Sandoval-Vargas Leidy ◽  
Elías Figueroa ◽  
Iván Valdebenito ◽  
...  

2014 ◽  
Vol 71 (1) ◽  
pp. 56-69 ◽  
Author(s):  
Brian C. Spence ◽  
E.J. Dick

The environmental cues that regulate smoltification and trigger downstream movement by salmon should vary across space in response to differences in the predictability of favorable conditions for migration and ocean entry. To examine this, we modeled the short-term outmigration probability of four coho salmon (Oncorhynchus kisutch) populations in three distinct geographic regions in relation to photoperiod, temperature, streamflow, lunar phase, and interactions among these variables. For smolts in Deer and Flynn creeks, Oregon (1960–1972), migration probability was influenced by numerous factors, including photoperiod, temperature (absolute and change), flow (absolute and change), and lunar phase, with certain factors interacting. Smolts from Carnation Creek, British Columbia (1972–1986) responded to a similarly diverse suite of factors (excluding lunar phase), though in somewhat different ways. In contrast, migration timing of smolts in Sashin Creek, Alaska (1959–1969) was best explained by a model that included only photoperiod, temperature, and the interaction between these terms. These population differences suggest fundamental differences across regions in the selection processes operating in both marine and freshwater environments.


Author(s):  
Shem Unger ◽  
Reuben R Goforth ◽  
Olin E Rhodes ◽  
Thomas Floyd

Freshwater ecosystems are increasingly impacted by anthropogenic elevated levels of suspended sediment that may negatively affect aquatic organisms, including salamanders. While increasing fine sediment in streams has been suggested as a reason for population declines, to date no study has empirically assessed the effect of suspended sediment on gilled larval Eastern Hellbenders (Cryptobranchus alleganiensis Daudin, 1803), a critical life history stage and species of conservation concern. We used custom respirometers to elucidate effects of suspended sediments on larval Hellbender oxygen uptake in trials conducted in situ in Georgia streams. Mean oxygen uptake increased and was significantly higher in trials when larval salamanders were exposed to suspended sediment (mean = 5.06 O2 mg/L, 800 mg/L sediment treatment vs 2.25 O2 mg/L, 0.00 mg/L sediment control). This may indicate elevated physiological stress in response to short term exposure to suspended sediments. Qualitatively, individuals in both groups exhibited rocking behavior in response to low oxygen (hypoxia), albeit at different frequencies (sediment exposure = 7.6 rocks per minute and control = 2.1 rocks per minute). Larval salamanders may be able to temporarily compensate for low oxygen through increased rocking behavior when high suspended sediment loads are present, with future respirometry research needed.


1995 ◽  
Vol 14 (8) ◽  
pp. 1419-1423 ◽  
Author(s):  
Raymond D. Semlitsch ◽  
Massimiliano Foglia ◽  
Alexandra Mueller ◽  
Isabelle Steiner ◽  
Ennio Fioramonti ◽  
...  

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