Sublethal Responses of Coho Salmon (Oncorhynchus kisutch) to Suspended Sediments

1992 ◽  
Vol 49 (7) ◽  
pp. 1389-1395 ◽  
Author(s):  
James A. Servizi ◽  
Dennis W. Martens

Underyearling coho salmon (Oncorhynchus kisutch) were exposed to sublethal concentrations of Fraser River suspended sediments (SS) in the laboratory. Comparisons with other rivers indicated that Fraser River sediments caused the lowest turbidity for a given SS value. Blood sugar levels (y) were elevated and directly proportional to SS exposure (x) according to y = 5.79 + 4.23(x). Published blood sugar data for adult sockeye salmon (O. nerka) exposed to Fraser River SS were in agreement with the linear relationship for underyearling coho. Cough frequency was elevated approximately eightfold over control levels at 0.24 g SS∙L−1. No increase in cough frequency was observed at 0.02 g SS∙L−1. Avoidance was defined by movement to the surface to escape higher SS at depth. Mean avoidance (y) was related to SS by y = 0.077 + 4.457(x) − 1.547(x2) + 0.202(x3). Mean avoidance was less than 5% up to the inflection point at 2.55 g SS∙L−1 but rose to approximately 25% at 7.0 g SS∙L−1. Laboratory results indicated that sublethal responses could be expected at naturally occurring SS levels in the Fraser River.

1991 ◽  
Vol 48 (3) ◽  
pp. 493-497 ◽  
Author(s):  
James A. Servizi ◽  
Dennis W. Martens

Tolerance of underyearling coho salmon (Oncorhynchus kisutch) to Fraser River suspended sediments (SS) at 7 °C was independent of season of the year. However, coho of 0.52 g (4.0 cm) possessed only 35% of the tolerance of larger specimens. Tolerance to SS was temperature dependent, with 96-h LC50 at 1 and 18 °C being 47 and 33%, respectively, of the value at 7 °C. Tolerance was further reduced among underyearling coho which were later found to have a viral kidney infection. Cough reflex, oxygen transfer, oxygen saturation levels, metabolic rates, and capacity to do work all probably affect the relationship between SS tolerance and temperature.


1985 ◽  
Vol 42 (12) ◽  
pp. 2020-2028 ◽  
Author(s):  
Eric B. Taylor ◽  
J. D. McPhail

Ten populations of juvenile coho salmon, Oncorhynchus kisutch, from streams tributary to the upper Fraser River, the lower Fraser River, and the Strait of Georgia region were morphologically compared. Juveniles from coastal streams (Fraser River below Hell's Gate and the Strait of Georgia) were more robust (deeper bodies and caudal peduncles, shorter heads, and larger median fins) than interior Juveniles. Discriminant function analysis indicated that juvenile coho could be identified as to river of origin with 71% accuracy. Juvenile coho from coastal streams were less successfully classified as to stream of origin; however, juveniles could be successfully identified as either coastal or interior with 93% accuracy. Juvenile coho from north coastal British Columbia, Alaska, and the upper Columbia system also fitted this coastal and interior grouping. This suggests that a coastwide coastal–interior dichotomy in juvenile body form exists. Three populations (one interior and two coastal) were studied in more detail. In these populations the coastal versus interior morphology was consistent over successive years, and was also displayed in individuals reared from eggs in the laboratory. Adult coho salmon also showed some of the coastal–interior morphological differences exhibited by juveniles. We concluded that the morphological differences between coastal and interior coho salmon are at least partially inherited.


1973 ◽  
Vol 30 (6) ◽  
pp. 831-834 ◽  
Author(s):  
Gary Wedemeyer

A rapid (3 min) but sublethal temperature increase from 10 to 20 imposed a greater stress on juvenile coho salmon (Oncorhynchus kisutch) than on juvenile steelhead trout (Salmo gairdneri). Both species suffered hyperglycemia, hypocholesterolemia, increased blood hemoglobin, and decreased blood sugar regulatory precision, but the steelhead recovered more quickly. Acid–base equilibrium was essentially unaffected, and only the coho suffered any significant interrenal vitamin C depletion. Vitamin C normalization required about 24 hr.


1976 ◽  
Vol 33 (8) ◽  
pp. 1771-1778 ◽  
Author(s):  
John Spinelli ◽  
Conrad Mahnken

The use of dogfish (Squalus acanthias) meal as a complete replacement for herring or other low mercury (Hg) content fish meal in rations intended for rearing cultured salmon introduces the risk of producing fish that exceed the current U.S. FDA tolerance level of 0.5 ppm Hg. The amount of Hg that accumulates in the muscle is related not only to the total Hg content of the fish, but is probably also related to the form in which it is present in the diet and to other constituents that may react with the Hg in the diet. Our results indicate that dogfish meal may be used as a partial (< 50%) replacement for the fish meal portion of the diet without encountering Hg values (in the muscle) that exceed 0.5 ppm Hg. No evidence was found that naturally occurring chelating agents in dehydrated orange peel or polygalacturonic acid–cellulose complexes (PG) have the ability to chelate and prevent the deposition of Hg in either the muscle or the liver of the fish. It was observed that growth is decreased in coho salmon (Oncorhynchus kisutch) fed OMP-type diets in which 50% or more of herring meal was replaced with dogfish meal.


1984 ◽  
Vol 41 (11) ◽  
pp. 1546-1551 ◽  
Author(s):  
K. J. Puckett ◽  
L. M. Dill

The relationship between oxygen consumption rate (milligrams per kilogram per hour) and sustained swimming speed (calculated from tailbeat frequency) was determined for 1.2-g juvenile coho salmon (Oncorhynchus kisutch) at 15 °C. The data are best described by the following equation: log oxygen consumption rate = 2.2 + 0.13 (body lengths-s−1). This relationship is very similar to that extrapolated for sockeye salmon (O. nerka) of the same size, thus potentially enabling researchers to utilize the extensive sockeye data base to predict metabolic rates of coho. The oxygen consumption rate during burst swimming (9 body lengths∙s−1) was also determined. The burst swimming metabolic rate (38 000 mgO2∙kg−1∙h−1) is nearly 40 times greater than the maximum sustained swimming metabolic rate.


1978 ◽  
Vol 35 (1) ◽  
pp. 8-11 ◽  
Author(s):  
J. E. Sanders ◽  
K. S. Pilcher ◽  
J. L. Fryer

Juvenile coho salmon (Oncorhynchus kisutch), sockeye salmon (O. nerka), and steelhead trout (Salmo gairdneri) were infected by intraperitoneal injection of a suspension of the causative organism of bacterial kidney disease at seven experimental temperatures from 3.9 to 20.5 °C. In coho salmon and steelhead trout percent mortality was maximal (78–100%) in the range of 6.7–12.2 °C. As the temperature increased above 12.2 °C mortality declined progressively; at 20.5 °C it was only 8–14%. The two highest temperatures had some suppressing effect on the disease, which was greatest at 20.5 °C. In sockeye salmon this was not apparent, as percent mortality was essentially 100% at all temperatures from 6.7 to 20.5 °C; this species appeared to be highly susceptible to the disease agent. Temperature also influenced the mean number of days between infection and death. This interval was shortest in all three species of salmonids at the higher temperatures, varying from 21 to 34 days at 15.0–20.5 °C. It increased progressively as temperature decreased below this range; at 6.7 °C it varied from 60 to 71 days among the three species. Key words: bacterial kidney disease, temperature, salmonids, Corynebacterium, coho salmon, sockeye salmon, steelhead trout


1994 ◽  
Vol 51 (12) ◽  
pp. 2843-2855 ◽  
Author(s):  
Richard J. Beamish ◽  
Chrys-Ellen M. Neville ◽  
Barbara L. Thomson ◽  
Paul J. Harrison ◽  
Mike St. John

We identified years of anomalously high and low discharge from the Fraser River and compared these years with indices of anomalously high and low production of Pacific salmon (Oncorhynchus spp.) and Pacific herring (Clupea pallasi). For chinook (O. tshawytscha) and coho salmon (O. kisutch), we found that brood years that went to sea in a year when the Fraser River discharge was very high compared with the previous year virtually never had an index of production that was higher than the previous year. Similarly, brood years that went to sea in a year when the Fraser River discharge was very low compared with the previous year almost never had an index of productivity that was lower than the previous year. The analysis identified a weaker association between extreme discharge anomalies and chum salmon (O. keta) production. A close association was not found between extreme discharge anomalies and pink salmon (O. gorbuscha), sockeye salmon (O. nerka), or herring production. The relationships identify a connection between annual fluctuations in river flow and production of some marine fishes and may be of use in forecasting abundance changes.


Sign in / Sign up

Export Citation Format

Share Document