The Behaviour of Chum, Pink and Coho Salmon in Relation to their Seaward Migration

1951 ◽  
Vol 8b (4) ◽  
pp. 241-263 ◽  
Author(s):  
William S. Hoar
Keyword(s):  
Fresh Water ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Water Levels ◽  
Salmon Fry ◽  
Seaward Migration ◽  
Active Swimming ◽  
Increased Activity ◽  
Downstream Movement ◽  
Marked Tendency

In fresh water, chum and pink salmon fry form schools or mills, are constantly active both day and night, show positive rheotaxis and move into fast water. This activity takes them into the swiftest currents. At night loss of visual and contact stimuli reduces the intensity of the rheotactic response and results in downstream movement. An active swimming downstream occurs only with unusually high temperatures. Coho salmon fry occupy and defend territory, maintain definite positions in relation to particular objects in their environment, show a less marked tendency to move into fast water and are quiet at night. They are thus displaced downstream to a much lesser degree. Coho smolts, in contrast to the fry, demonstrate a lowered threshold for stimulation both day and night, a tendency to aggregate and a lessening in territory behaviour. During the day smolts group in deeper water or under cover. At night they rise to the surface and manifest increased activity which, in swift water, will result in displacement seaward. Pronounced changes in temperature modify these reactions. Sudden elevation of water levels hastens the downstream displacement.

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

Notes on the Seaward Migration of Pink and Chum Salmon Fry

1955 ◽  
Vol 12 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Ferris Neave
Keyword(s):  
Vertical Distribution ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Strong Light ◽  
Salmon Fry ◽  
Seaward Migration ◽  
Schooling Behaviour ◽  
And Migration ◽  
A Current ◽  
Downstream Movement

The seaward migration of pink and chum salmon fry takes place at night. Strong light is avoided. In pink salmon negative rheotaxis (swimming with a current) is strongly developed and migration is not primarily effected by random swimming and passive displacement. Downstream movement is mainly at or close to the surface. In slack water vertical distribution is more uniform. In the shortest streams examined, each night's migrants appeared to reach the sea before daybreak. In a longer stream, fry were seen to bury themselves at the onset of daylight. After being held in fresh water for an undetermined period, fry show positive rheotaxis and schooling behaviour and no longer avoid light. Behaviour of fry after reaching the sea also differs from that shown during actual migration. Changes in behaviour may coincide with commencement of feeding.

THE THYROID GLAND IN RELATION TO THE SEAWARD MIGRATION OF PACIFIC SALMON

1950 ◽  
Vol 28d (3) ◽  
pp. 126-136 ◽  
Author(s):  
William S. Hoar ◽  
G. Mary Bell
Keyword(s):  
Fresh Water ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
River Estuary ◽  
Salt Balance ◽  
Thyroid Activity ◽  
Salmon Fry ◽  
Thyroid Glands ◽  
Seaward Migration

Histological examination of the thyroid glands from chum salmon fry taken in the river, estuary, or sea shows the organ to be in a quiescent condition at the time of migration. If, however, this species is retained in fresh water for two or three months the gland becomes extremely hyperplastic. The pink salmon thyroid behaves in essentially the same way as that of the chum, but migrating pink fry taken at great distances from the sea have active glands. The thyroids of yearling coho and sockeye moving into the sea display heightened activity. Thyroid activity is apparently greater in coho migrants taken later in the season from the headwaters of rivers. In part, the heightened thyroid activity seen in these migrating Pacific salmon is probably a spring-time seasonal change. It seems, however, to be more particularly related to the increased metabolic work of osmotic regulation and salt balance in a fish physiologically prepared for life in the sea. In general, this study suggests that the increased thyroid activity seen in young migrating salmonoids is largely due to increased demands for thyroid hormone in the metabolism of a fish no longer completely adjusted physiologically to fresh water.

Density, growth, and change in density of coho salmon and rainbow trout in three Lake Michigan tributaries

1983 ◽  
Vol 61 (5) ◽  
pp. 1120-1127 ◽  
Author(s):  
L. M. Carl
Keyword(s):  
Rainbow Trout ◽  
Growth Rates ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Daily Growth ◽  
Salmon Fry ◽  
Daily Change ◽  
Early Fall ◽  
Growth And Change ◽  
Downstream Movement

Coho salmon spawning peaked in the late fall. Spawning densities ranged from fewer than 5 coho salmon per hectare up to 90 fish per hectare. Subyearling coho salmon densities ranged from 10 to 60 fish per 100 m2 in June and dropped to 5–20 fish by early fall. Coho salmon fry increased in length from 40 mm in early May, to over 120 mm by smolt out-migration in the following April. Coho salmon instantaneous daily change in density coefficients ranged from 0.004 to 0.019 and were dependent on initial coho density. Daily coho salmon growth rates ranged from 0.38 to 0.60 mm per day and were not dependent on initial coho salmon density. Downstream movement of rainbow trout fry began in May, and continued into July. In the spring 10–20 yearlings and one to five 2-year-olds per 100 m2 were present. Most fry emerged in June at a size of 25 mm and grew to 85 mm by fall. Daily growth rates varied from 0.23 to 0.45 mm per day for yearling rainbow trout and were not correlated with rainbow trout density.

Toxicity and Avoidance Tests with Prudhoe Bay Oil and Pink Salmon Fry

1973 ◽  
Vol 1973 (1) ◽  
pp. 667-670 ◽  
Author(s):  
Stanley D. Rice
Keyword(s):  
Fresh Water ◽  
Oil Pollution ◽  
Pink Salmon ◽  
Marine Resources ◽  
Migration Behavior ◽  
Salmon Fry ◽  
Avoidance Tests ◽  
Oil Toxicity ◽  
National Marine Fisheries Service ◽  
Prudhoe Bay

ABSTRACT With the potential of oil pollution harming Alaska's marine resources, experiments were conducted at the National Marine Fisheries Service, Auke Bay Fisheries Laboratory to determine the concentrations of Prudhoe Bay crude oil that are acutely toxic to pink salmon fry in fresh water and seawater and also the concentrations of this oil that the fry would avoid. Observed 96-hour TLM values were 88 mg of oil/liter of water in fresh water and 213 mg/liter in seawater in June and 110 mg/liter in seawater in August. Among fry held in seawater, older fry were more susceptible to oil toxicity than younger fry and older fry were also more sensitive in their detection and avoidance of oil; older fry in seawater avoided oil concentrations as low as 1.6 mg of oil/liter of water. The avoidance of oil by salmon fry was quite apparent and suggests that there is potential for oil pollution to change their migration behavior.

Toxicity of Various Formulations of 2,4-D to Salmonids in Southeast Alaska

1974 ◽  
Vol 31 (4) ◽  
pp. 480-485 ◽  
Author(s):  
William R. Meehan ◽  
Logan A. Norris ◽  
Howard S. Sears
Keyword(s):  
Sockeye Salmon ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Butyl Ester ◽  
Southeast Alaska ◽  
Dolly Varden Char ◽  
Salmon Fry ◽  
Percent Mortality ◽  
The Mean ◽  
Made In

To determine acute toxicity to juvenile (1) pink, chum, coho, and sockeye salmon, (2) Dolly Varden char, and (3) rainbow trout, 2,4-D acid, butyl and isooctyl esters were tested in southeast Alaska. A comparable test was made in Oregon using coho salmon fingerlings. The mean percent mortality after 96 h and the highest concentration of herbicide that did not produce any mortality were determined for each formulation tested.At less than 50 ppm 2,4-D acid produced no mortality except in pink salmon fry. The butyl ester was most toxic causing nearly complete mortality in all species at concentrations > 1.0 ppm and the isooctyl ester least toxic of the ester formulations. Alaskan and Oregon coho fingerlings were similar in their responses to 2,4-D acid, butyl and isooctyl esters. The toxicities of three different formulations of isooctyl ester, a PGBE ester, and butyl ester to Alaskan coho fingerlings were also determined. There were few or no differences in toxicity among isooctyl ester formulations. The butyl and PGBE esters were similar in toxicity.

Behavioral Ecology of Chum Salmon Fry (Oncorhynchus keta) in a Small Estuary

1974 ◽  
Vol 31 (1) ◽  
pp. 83-92 ◽  
Author(s):  
J. C. Mason
Keyword(s):  
Fresh Water ◽  
Behavioral Ecology ◽  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Natural Systems ◽  
Active Selection ◽  
Resource Managers ◽  
Salmon Fry ◽  
Seaward Migration ◽  
And Behavior

Chum salmon fry (Oncorhynchus keta) in the estuary of a small coastal stream exploited fresh water, estuarine, and marine food chains and, by so doing, were exposed to marked, daily fluctuations in salinity that demanded active selection of fresh water on ebbing tides day and night. The resulting delay in seaward migration and associated behavioral observations are inadequately reflected in published accounts of the life history and behavior of chum fry in natural systems and laboratory situations, and the downstream displacement theory. The biological basis for delayed seaward migration of chum fry merits the attention of fishery researchers and resource managers alike.

Emigration and Production of Hatchery Coho Salmon (Oncorhynchus kisutch) Stocked in Streams Draining an Old-growth and a Clear-cut Watershed

1987 ◽  
Vol 44 (8) ◽  
pp. 1397-1407 ◽  
Author(s):  
Robert E. Bilby ◽  
Peter A. Bisson
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Old Growth ◽  
Trophic Conditions ◽  
Temperature Changes ◽  
Gross Photosynthesis ◽  
Clear Cut ◽  
Salmon Fry ◽  
Streamflow Change ◽  
Downstream Movement

Downstream movement of coho salmon fry (Oncorhynchus kisutch) stocked in old-growth and clear-cut watersheds occurred in three phases: (1) a brief period of heavy emigration immediately after stocking, (2) relatively little movement throughout most of the summer, and (3) intermittent heavy emigration during early autumn freshets. Coho emigrated whenever a streamflow change ≥ 3%∙d−1 occurred, but movement nearly ceased at flows above a certain level. Temperature changes were less important than discharge in triggering movement. When high densities were stocked, emigrant fry were smaller than residents. When low densities were stocked, emigration after the initial pulse of downstream movement was generally lower and there were no size differences between emigrants and residents. Production in the clear-cut was greater than in the old-growth watershed. Proportionately fewer fish emigrated from the old-growth stream, but when population densities were high, mortality in the old-growth exceeded the clear-cut. Greater emigration from the clear-cut site was possibly related to a scarcity of pools. Although the old-growth stream possessed better rearing habitat, less food may have been available, as suggested by gross photosynthesis rates 50% lower than in the clear-cut stream. Coho production therefore appeared to be most strongly influenced by trophic conditions, while volitional residency was most strongly influenced by habitat quality.

Effect of incubation temperature on the development of five species of Pacific salmon (Oncorhynchus) embryos and alevins

1988 ◽  
Vol 66 (1) ◽  
pp. 266-273 ◽  
Author(s):  
C. B. Murray ◽  
J. D. McPhail
Keyword(s):  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Embryo Survival ◽  
Salmon Fry ◽  
Incubation Temperatures

Embryo and alevin survival, time to hatching and emergence, and alevin and fry size of five species of Pacific salmon (Oncorhynchus) were observed at five incubation temperatures (2, 5, 8, 11, and 14 °C). No pink (Oncorhynchus gorbuscha) or chum (O. keta) salmon embryos survived to hatching at 2 °C. Coho (O. kisutch) and sockeye (O. nerka) salmon had higher embryo survival at 2 °C than chinook (O. tschawytscha) salmon. At 14 °C, chum, pink, and chinook salmon had higher embryo survival than coho or sockeye salmon. In all species, peaks of embryo mortality occurred at specific developmental stages (completion of epiboly, eye pigmentation, and hatching). Alevin survival to emergence was high for all species, except for coho and pink salmon at 14 °C. Hatching and emergence time varied inversely with incubation temperature, but coho salmon hatched and emerged sooner at all temperatures than the other species. Coho and sockeye salmon alevins were larger at 2 °C, pink, chum, and chinook salmon alevins were larger at 5 and 8 °C. Coho salmon fry were larger at 2 °C, chinook and chum salmon fry were larger at 5 °C, and sockeye and pink salmon fry were larger at 8 °C. High incubation temperatures reduced fry size in all species. Each species of Pacific salmon appears to be adapted to different spawning times and temperatures, and thus indirectly to specific incubation temperatures, to ensure maximum survival and size and to maintain emergence at the most favorable time each year.

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