Male Coho Salmon Research Articles

Acutely Lethal Levels of Cadmium, Copper, and Zinc to Adult Male Coho Salmon and Steelhead

Flow-through acute toxicity tests of cadmium, copper, and zinc were conducted with adult male coho salmon (Oncorhynchus kisutch) and adult male steelhead (Salmo gairdneri). The 96-h LC50 values for copper were 46 and 57 μg/liter, and for zinc were 905 and 1,755 μg/liter, for coho salmon and steelhead, respectively. Mortality induced by cadmium was slow in onset, but 50% mortality occurred after more than a week at 3.7 μg/liter for coho salmon and 5.2 μg/liter for steelhead. Hardness and alkalinity of the water supply were higher during the toxicity tests with steelhead, complicating direct comparisons between the two species.

Primary and Secondary Effects of Stress in Fish: Some New Data with a General Review

Handling in fish induces perturbations of various biological parameters which have been investigated or reviewed in an attempt to analyse and quantify the resulting stress. Endocrine changes, being early consequences of stress, are referred to as primary effects. Original data obtained on coho (Oncorhynchus kisutch), sockeye (O. nerka), and chinook (O. tshawytscha) salmon show that all types of stress result in an increase in circulating catecholamines, mainly adrenaline. There is no quantitative difference in response intensity between the species studied but large individual variations exist. In mature male coho salmon, struggling and hypoxia also resulted in an increase of plasmatic corticosteroids. Secondary effects occur as a result of these endocrine changes. Metabolic disturbances include a pronounced increase in blood glucose, and either a decrease or an increase of plasmatic free fatty acid (FFA) according to the species. These metabolic disturbances brought about by stress of short duration are shown to be of relatively long duration. Recent advances in the understanding of osmoregulatory processes show that the action of catecholamines on gill permeability may explain the stress-induced water imbibition of fish in fresh water and the dehydration of fish in seawater. Beyond some practical considerations, the results reported open up the possibility for genetic selection of varieties of high or low response to stress.

THE METABOLISM OF INOSITOL IN SALMON: I. THE DISTRIBUTION OF RADIOACTIVITY IN ACID-SOLUBLE EXTRACTS OF COHO SALMON FOLLOWING INTRAPERITONEAL AND INTRA-ARTERIAL INJECTIONS OF 2-C14-MYOINOSITOL

Male coho salmon held in captivity for only a few days were injected intra-peritoneally and intra-arterially with 2-C14-myoinositol. Several hours later the cohoes were anesthetized and frozen in dry ice. After overnight storage, perchloric extracts were made of the major organs and tissues and the relative C14content of the extracts was determined. Most of the radioactivity of the extracts was not adsorbed by charcoal. Only the liver and to a lesser extent the flesh and kidney contained radioactivity in the nucleotide fraction. Of the material not adsorbed to charcoal, most of the radioactivity of the kidney, milt, and gut extracts were not held by Dowex-1-formate while that of the head and liver extracts was about equally divided between the water and formic acid eluants of the column. The two methods of injection resulted in no major differences in the relative amounts of C14labelling in the various tissue components.

THE METABOLISM OF INOSITOL IN SALMON: I. THE DISTRIBUTION OF RADIOACTIVITY IN ACID-SOLUBLE EXTRACTS OF COHO SALMON FOLLOWING INTRAPERITONEAL AND INTRA-ARTERIAL INJECTIONS OF 2-C14-MYOINOSITOL

Male coho salmon held in captivity for only a few days were injected intra-peritoneally and intra-arterially with 2-C14-myoinositol. Several hours later the cohoes were anesthetized and frozen in dry ice. After overnight storage, perchloric extracts were made of the major organs and tissues and the relative C14content of the extracts was determined. Most of the radioactivity of the extracts was not adsorbed by charcoal. Only the liver and to a lesser extent the flesh and kidney contained radioactivity in the nucleotide fraction. Of the material not adsorbed to charcoal, most of the radioactivity of the kidney, milt, and gut extracts were not held by Dowex-1-formate while that of the head and liver extracts was about equally divided between the water and formic acid eluants of the column. The two methods of injection resulted in no major differences in the relative amounts of C14labelling in the various tissue components.