EFFECTS OF CHLORINATED BIPHENYLS AND PETROLEUM HYDROCARBONS ON THE ACTIVITY OF HEPATIC ARYL HYDROCARBON HYDROXYLASE OF COHO SALMON (Oncorhynchus kisutch) AND CHINOOK SALMON (O. tshawytscha)

1977 ◽  
pp. 323-331 ◽  
Author(s):  
Edward H. Gruger ◽  
Marleen M. Wekell ◽  
Paul A. Robisch
Keyword(s):  
Chinook Salmon ◽  
Petroleum Hydrocarbons ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Aryl Hydrocarbon Hydroxylase ◽  
Aryl Hydrocarbon

Effects of Early Rearing Environment on Stress Response, Immune Function, and Disease Resistance in Juvenile Coho (Oncorhynchus kisutch) and Chinook Salmon (O.tshawytscha)

1993 ◽  
Vol 50 (4) ◽  
pp. 759-766 ◽  
Author(s):  
Kira Salonius ◽  
George K. Iwama
Keyword(s):  
Disease Resistance ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Vibrio Anguillarum ◽  
Oncorhynchus Kisutch ◽  
Significant Rise ◽  
Wild Fish ◽  
Handling Stress ◽  
Hatchery Fish ◽  
Natural Water Body

Coho (Oncorhynchus kisutch) and chinook salmon (0. tshawytscha) from aquaculture and wild environments were subjected to handling (30–60 s of netting and aerial emersion) and disease challenges. Plasma cortisol concentrations ([cortisol]pl) in both coho and chinook salmon from wild environments were significantly elevated 4 h after handling. Colonized coho salmon (hatchery-reared fish, transported into a natural water body as fry) responded in a similar fashion to wild fish, while those reared entirely in the hatchery showed no significant rise in [cortisol]pl. The responses to handling stress were retained in wild and colonized coho salmon after 7 mo of hatchery rearing. A transient increase in the leukocyte to red blood cell ratio in both wild and hatchery-reared chinook salmon occurred 4 h after handling. Handling signficantly decreased the antibody-producing cell (APC) number in wild fish and elevated their [cortisol]plrelative to hatchery fish. Wild fish had the highest APC number among the three groups before the handling. No difference in resistance to Vibrio anguillarum was apparent in coho and chinook salmon among the different rearing environments, although chinook salmon were generally more susceptible; disease resistance was reduced in wild coho salmon after 7 mo of rearing in a hatchery.

Phoma herbarum, a Fungal Plant Saprophyte, as a Fish Pathogen

1975 ◽  
Vol 32 (9) ◽  
pp. 1648-1652 ◽  
Author(s):  
A. J. Ross ◽  
W. T. Yasutake ◽  
Steve Leek
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Histopathological Examination ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Fish Pathogen ◽  
Experimental Infections ◽  
Phoma Herbarum ◽  
Low Incidence

Phoma herbarum, a fungal plant saprophyte, was isolated from diseased hatchery-reared coho salmon (Oncorhynchus kisutch), chinook salmon (O. tshawytscha), and rainbow trout (Salmo gairdneri). The disease was observed at 10 national fish hatcheries in Washington and Oregon, but the low incidence of experimental infections indicate that it is only weakly contagious. Histopathological examination suggests that the air bladder is one of the primary organs infected. The visceral organs are also affected in both natural and experimental infections.

The Harmful Phytoplankter Chaetoceros concavicornis Causes High Mortalities and Leucopenia in Chinook Salmon (Oncorhynchus tshawytscha) and Coho Salmon (O. kisutch)

1994 ◽  
Vol 51 (11) ◽  
pp. 2493-2500 ◽  
Author(s):  
C. Z. Yang ◽  
L. J. Albright
Keyword(s):  
Immune System ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Goblet Cells ◽  
Mortality Rates

Chaetoceros concavicornis is a harmful phytoplankter that occurs in many temperate coastal seawaters and can cause fin fish mortalities when present at concentrations as low as 5 cells∙mL−1. At even lower concentrations, this diatom can stress salmonids to such an extent that they may express a disease to which they are most prone at the time of C. concavicornis exposure. We report mortality rates of coho salmon (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha) exposed to different concentrations of C. concavicornis. Our data indicate that in the presence of harmful concentrations of C. concavicornis, blood hematocrit and erythrocyte, glucose, and lactate concentrations of yearling chinook salmon (O. tshawytscha) increase. The microridges of the primary lamellae decreased in prominence in the presence of harmful concentrations of this phytoplankter, while the goblet cells became more prominent and more numerous. Neutrophil, lymphocyte, and thrombocyte concentrations in the blood became depleted. These data suggest that suppression of a portion of the Chinook's immune system is occurring which may partially explain the earlier observation that salmonids cultured in the presence of harmful C. concavicornis phytoplankton became more susceptible to disease, including Vibrio infections.

Effect of Changes in Streamflow on the Microhabitat Use and Movements of Sympatric Juvenile Coho Salmon (Oncorhynchus kisutch) and Chinook Salmon (O. tshawytscha) in a Natural Stream

1994 ◽  
Vol 51 (7) ◽  
pp. 1644-1652 ◽  
Author(s):  
C. S. Shirvell
Keyword(s):  
Chinook Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Microhabitat Use ◽  
Net Energy ◽  
Optimal Position ◽  
Juvenile Chinook Salmon ◽  
Natural Stream ◽  
Juvenile Chinook ◽  
Seasonal Streamflow

The microhabitats at positions selected by juvenile coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha) following a change in streamflow differed from microhabitats occupied at normal streamflows. At drought streamflow (37% mean seasonal streamflow (MSF)), juvenile coho salmon selected slower, darker, and higher sites above the streambed (P < 0.05) than sites selected at normal (75% MSF) or flood (159% MSF) flows. Juvenile chinook salmon microhabitat use changed similarly with changes in streamflow, but the differences were not significant. Up to one fifth of the fish chose positions with faster water velocities than those available either 30 cm above or 30 cm lateral to them. These fish chose positions inconsistent with the hypothesis of optimal position selection based on maximizing net energy gain. On average, fish moved 6.8 m following a change in streamflow. Juvenile coho salmon generally moved upstream in response to decreasing streamflows and downstream in response to increasing streamflows. Juvenile chinook salmon tended to move offshore and downstream in response to all streamflow changes. These results show that juvenile coho and chinook salmon will move to find suitable microhabitat following a change in streamflow and that the microhabitats are not the same at all streamflows.

Somatolactin, a novel pituitary protein: purification and plasma levels during reproductive maturation of coho salmon

1992 ◽  
Vol 133 (3) ◽  
pp. 393-403 ◽  
Author(s):  
M. Rand-Weaver ◽  
P. Swanson ◽  
H. Kawauchi ◽  
W. W. Dickhoff
Keyword(s):  
Salmo Salar ◽  
Chinook Salmon ◽  
Plasma Levels ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Cross Reactivity ◽  
Standard Curve ◽  
Reproductive Maturation ◽  
Final Maturation ◽  
Highly Correlated

ABSTRACT Somatolactin (SL), a newly discovered fish pituitary protein belonging to the GH/prolactin family, was isolated from coho salmon (Oncorhynchus kisutch). Antibodies were raised to purified coho SL, and a homologous radioimmunoassay was developed and validated. The assay was specific for SL as indicated by the absence of cross-reactivity with coho salmon GH, gonadotrophins I and II and less than 0·2% cross-reaction to prolactin. Serial dilutions of plasma and pituitary extracts from Oncorhynchus species including coho salmon, chinook salmon and rainbow trout were parallel to the coho salmon SL standard curve. Displacement curves for dilutions of Atlantic salmon (Salmo salar) plasma, but not pituitary extract were parallel to the standards. Plasma levels of SL were measured in coho salmon throughout the final year of reproductive maturation. During the period of gonadal growth, plasma SL levels increased and were highly correlated to oestradiol levels in females and 11-ketotestosterone levels in males. Peak levels of SL were observed at the time of final maturation and spawning in both sexes. It is hypothesized that SL may regulate some physiological aspect of reproduction. Journal of Endocrinology (1992) 133, 393–403

Relation of Water Temperature to Flexibacter columnaris Infection in Steelhead Trout (Salmo gairdneri), Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon

1975 ◽  
Vol 32 (9) ◽  
pp. 1553-1559 ◽  
Author(s):  
R. A. Holt ◽  
J. E. Sanders ◽  
J. L. Zinn ◽  
J. L. Fryer ◽  
K. S. Pilcher
Keyword(s):  
Water Temperature ◽  
Experimental Infection ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Disease Process ◽  
Salmo Gairdneri ◽  
Contact Method ◽  
Steelhead Trout ◽  
Time To Death

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.

Endohelminths of salmonids from two localities in eastern Lake Michigan, with emphasis on Echinorhynchus salmonis

1989 ◽  
Vol 67 (6) ◽  
pp. 1604-1607 ◽  
Author(s):  
Patrick M. Muzzall
Keyword(s):  
Chinook Salmon ◽  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salvelinus Namaycush ◽  
Salmo Gairdneri ◽  
Brown Trout Salmo Trutta

Adult salmonids (101 chinook salmon, Oncorhynchus tshawytscha; 7 coho salmon, Oncorhynchus kisutch; 56 lake trout, Salvelinus namaycush; 6 steelhead, Salmo gairdneri; and 2 brown trout, Salmo trutta) were collected from eastern Lake Michigan (Ludington and Manistee, Michigan) in July–September 1986, and examined for helminths. Eight species (three Cestoda, three Nematoda, two Acanthocephala) were found in the digestive tract and other viscera. Echinorhynchus salmonis and Eubothrium salvelini were the most common helminths found. The intensity of E. salmonis significantly increased as chinook salmon became older and longer.

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