External Morphology of the Pink Salmon, Oncorhynchus gorbuscha, Introduced into Lake Superior

1979 ◽  
Vol 36 (10) ◽  
pp. 1283-1287 ◽  
Author(s):  
Richard E. Berg
Keyword(s):  
Key Words ◽  
Lake Superior ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Morphometric Measurements ◽  
Male Fish ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
The Pacific ◽  
Male Head ◽  
Degree Of Differentiation

Meristic and morphometric measurements were taken from 33 male and 44 female mature pink salmon, Oncorhynchus gorbuscha, collected in three Lake Superior tributaries in Marquette County, Michigan. Significant sexual differences were found for eight characteristics in males and two in females. The male fish had a greater degree of differentiation in the head and hump regions; females had larger and longer anal fins. The Lake Superior fish were found to have shorter bodies, larger and longer fins, and more exaggerated development in the male head and hump than has been reported for the Pacific populations. Key words: pink salmon, salmonids, exotic species, Lake Superior, morphology

First Evidence for Even-Year Spawning Pink Salmon, Oncorhynchus gorbuscha, in Lake Superior

1978 ◽  
Vol 35 (10) ◽  
pp. 1373-1376 ◽  
Author(s):  
Wen-hwa Kwain ◽  
J. A. Chappel
Keyword(s):  
Great Lakes ◽  
Key Words ◽  
Lake Superior ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha

Nine even-year spawning pink salmon, Oncorhynchus gorbuscha, were taken in Steel River, Lake Superior, Ontario, in 1976. The possible origin of these fish was from unknown plantings or spawning of 3-yr-old, odd-year spawning pink salmon. Key words: Great Lakes, distribution, salmon maturation, spawning age, introduced salmon

Migratory dynamics and characteristics of breeding pink salmon (Oncorhynchus gorbuscha) from the Carp River, eastern Lake Superior

1990 ◽  
Vol 68 (4) ◽  
pp. 684-693 ◽  
Author(s):  
Douglas B. Noltie
Keyword(s):  
Lake Superior ◽  
Pink Salmon ◽  
Life Cycles ◽  
Oncorhynchus Gorbuscha ◽  
Gonad Maturation ◽  
Breeding Ecology ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Light Levels ◽  
Breeding Migration ◽  
Fish Remains

The pink salmon (Oncorhynchus gorbuscha) inhabiting the Great Lakes are unique to their species, the completion of their life cycles occurring entirely in fresh water. This report describes the breeding migration and characteristics of spawners from the Carp River, an eastern Lake Superior tributary 70 km north of Sault Ste. Marie, Ontario. Movement into the stream began at dusk each evening in 1983, seemingly in response to decreasing light levels. Nightly catch numbers varied through the 1983, 1984, and 1985 runs with date, river discharge, wind-generated turbulence, and water temperatures, although the influence of these factors differed with sex and season. Spawners varied in size through the runs each year but not in the same fashion. Spawner size and condition varied yearly in apparent response to prey abundance. Gonad maturation was complete on stream entry more often in males than in females, though this difference was less pronounced further upstream or after time spent in the river. Degree of secondary sexual character development, complete on stream entry in both sexes, differed in even- and odd-year spawners in relation to condition. The recovery rates of spawned-out males and females did not differ. Tagged fish wandered from the Carp River at a rate of at least 7%, many to spawn in adjacent streams. Despite between-year differences in some parameters, much of the breeding ecology of these fish remains comparable to that of anadromous pink salmon.

Use of the stratified-Petersen estimator in fisheries management: estimating the number of pink salmon (Oncorhynchus gorbuscha) spawners in the Fraser River

1998 ◽  
Vol 55 (2) ◽  
pp. 281-296 ◽  
Author(s):  
Carl James Schwarz ◽  
Carolyn Gail Taylor
Keyword(s):  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Fraser River ◽  
Differential Migration ◽  
Mark Recapture ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
The Pacific ◽  
Recent Developments

The simple-Petersen estimator is a well-known mark-recapture method to estimate animal abundance. Two key assumptions are equal catchability in both samples and complete mixing of tagged and untagged animals. If these are violated, severe bias can occur. The stratified-Petersen estimator can be used to account for some of the heterogeneity in catchability or mixing. In this paper, we first review recent developments in the stratified-Petersen experiment for fisheries audiences and demonstrate some of the practical problems that can occur that have not been discussed in the theoretical literature. Second, we present a case study to estimate the gross escapement of Fraser River pink salmon (Oncorhynchus gorbuscha) in 1991. The motivation for this study is a discrepancy of over 5 million fish between the estimates as derived by the Pacific Salmon Commission (PSC) (7.5 million fish based on a hydroacoustic method) and the Department of Fisheries and Oceans (DFO), Canada (13.0 million fish based on a mark-recapture method). One hypothesis put forward was that the discrepancy may be due to the use of a pooled-Petersen estimator when there is differential migration over time. The stratified-Petersen model suggests that little of this discrepancy can be explained by differential migration.

Differences in breeding Lake Superior pink salmon (Oncorhynchus gorbuscha (Walbaum)) associated with variation in thyroid hyperplasia

1988 ◽  
Vol 66 (12) ◽  
pp. 2688-2694 ◽  
Author(s):  
Douglas B. Noltie
Keyword(s):  
Lake Superior ◽  
Pink Salmon ◽  
Lesion Size ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Wide Range ◽  
Post Spawning ◽  
Delayed Maturation ◽  
Thyroid Hyperplasia ◽  
Lesion Severity

Pink salmon (Oncorhynchus gorbuscha (Walbaum)) from eastern Lake Superior exhibit various degrees of thyroid hyperplasia. A link between goitrogenesis and growth is suggested by the increased prevalence of large lesions among large fish of both sexes. Despite males being larger than females, however, lesion prevalence did not differ between the sexes. More large lesions occurred among late migrants, especially males, indicating a seasonal increase in hyperplasticity. Delayed stream entry occurred in overtly lesioned fish of both sexes, evidence of a possible inhibition of maturation. Males and females differed in condition (weight-at-length) with lesion severity. Females with overt lesions showed reduced secondary sexual character development, more so than males. The pre- and post-spawning testis characteristics of males generally did not differ with lesion size, although the testes of spawned-out males with large lesions did have higher water contents. In females, the reduced water content of eggs in severely lesioned individuals was evidence of delayed maturation. Enlarged livers occurred in badly lesioned females, but not in males. In neither sex did severely lesioned fish exhibit shorter breeding life-spans. In overview, this study demonstrates that a wide range of effects is associated with differences in the severity of thyroid hyperplasia exhibited by Lake Superior pink salmon, these also being mediated by apparent differences in physiology between the sexes.

Occurrence of Pink Salmon (Oncorhynchus gorbuscha) in Lake Huron

1975 ◽  
Vol 32 (3) ◽  
pp. 402-404 ◽  
Author(s):  
John J. Collins
Keyword(s):  
Lake Superior ◽  
Pink Salmon ◽  
Lake Huron ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha

Pink salmon (Oncorhynchus gorbuscha), which were introduced into Lake Superior in 1956 and have produced eight natural generations there, have now appeared in Lake Huron. The first pink salmon was taken in Ontario waters of Lake Huron in 1971. Successful spawning was observed in one tributary in 1973, indicating that pink salmon could become established in Lake Huron.

Intrapopulation Variation in the Breeding of Male Pink Salmon (Oncorhynchus gorbuscha) from a Lake Superior Tributary

1990 ◽  
Vol 47 (1) ◽  
pp. 174-179 ◽  
Author(s):  
Douglas B. Noltie
Keyword(s):  
Lake Superior ◽  
Pink Salmon ◽  
Life History Strategies ◽  
Oncorhynchus Gorbuscha ◽  
Breeding Ground ◽  
Spawning Ground ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Intrapopulation Variation ◽  
Morphological Studies ◽  
Proximate Factors

Studies of breeding pink salmon (Oncorhynchus gorbuscha) from the Carp River, eastern Lake Superior, indicate that males seek fertilizations using two behavioural tactics. In 1985, a large run resulted in high breeding ground densities. During this run, males that resembled females were seen seeking fertilizations by sneaking rather than by competing for proximity to females. Morphological studies in 1985 confirmed the presence of males resembling females, their secondary sexual characters (hump height) being relatively less developed than in typical males. Although in poorer condition, such female-like males were reproductively mature, had returned to spawn at ages typical for this population, and had committed biomass to gonad no differently than had typical males. Furthermore, their spawning performance did not differ from typical males, as assessed both by the amount of gonad they retained unspawned at death and by their spawning ground life expectancies. In contrast, males attempting to sneak fertilizations were not observed during the small 1984 run when densities were low and males were generally in better condition than in 1985. Together, these results indicate that male pink salmon exhibit alternative breeding tactics. However, the demonstration of these tactics appears linked more to proximate factors (density and condition) than to divergent life history strategies as in other salmonid species.

Epizootics of thyroid hyperplasia in Lake Superior and Lake Erie pink salmon (Oncorhynchus gorbuscha (Walbaum))

1988 ◽  
Vol 66 (12) ◽  
pp. 2676-2687 ◽  
Author(s):  
Douglas B. Noltie ◽  
John F. Leatherland ◽  
Miles H. A. Keenleyside
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Great Lakes ◽  
Lake Erie ◽  
Lake Superior ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Negative Effects ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Thyroid Hyperplasia

All Lake Superior and Lake Erie pink salmon (Oncorhynchus gorbuscha (Walbaum)) collected exhibited thyroid hyperplasia. Samples from British Columbia, however, were unaffected. In fish from Lake Superior, lesion sizes increased through a graded series and were correlated with increased body size. In contrast, almost all Lake Erie fish exhibited extreme hyperplasia regardless of body size. Pink salmon lesion histopathology differed markedly from that shown by Great Lakes coho (Oncorhynchus kisutch (Walbaum)) and chinook (Oncorhynchus ishawytscha (Walbaum)) salmon. Among Great Lakes populations, males and females were equally afflicted. Greater proportions of females entered their spawning streams with immature gonads in Lake Erie, where fish exhibited larger lesions. Indications are that males showed poorer secondary sexual character development there as well. Gonad weights in Lake Erie males were proportionally smaller than in Lake Superior males, and liver weights in Lake Superior fish were smaller than in British Columbia specimens. Thyroid hormone levels and lesion sizes were negatively correlated, providing evidence of hypothyroidism. These findings warn of potential water quality problems in Lake Superior, and suggest a useful means of assessing the goitrogenic potential of Great Lakes systems. Despite its negative effects, however, thyroid hyperplasia has not prevented the increase of pink salmon numbers and distribution in the Great Lakes.

Survival of pink salmon (Oncorhynchus gorbuscha) fry to adulthood following a 10-day exposure to the aromatic hydrocarbon water-soluble fraction of crude oil and release to the Pacific Ocean

1999 ◽  
Vol 56 (11) ◽  
pp. 2087-2098 ◽  
Author(s):  
I K Birtwell ◽  
R Fink ◽  
D Brand ◽  
R Alexander ◽  
C D McAllister
Keyword(s):  
Pacific Ocean ◽  
Crude Oil ◽  
Soluble Fraction ◽  
Pink Salmon ◽  
Water Soluble ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Water Soluble Fraction ◽  
The Pacific ◽  
The Pacific Ocean

Saltwater-acclimated, coded-wire tagged, and adipose fin clipped pink salmon (Oncorhynchus gorbuscha) fry were exposed for 10 days to seawater (control) or 25-54 μg·L-1 (low dose) or 178-349 μg·L-1 (high dose) of the water-soluble fraction (WSF) of North Slope crude oil. The WSF was composed primarily of monoaromatics and was acutely lethal to the fry: 96-h LC50 ranged from 1 to 2.8 mg·L-1. After exposure the fry (30 000 per treatment) were released into the Pacific Ocean to complete their life cycle. The experiment was replicated in 1990, 1991, and 1992. There was no consistent significant dose-dependent effect of the 10-day exposure to the crude oil WSF on growth of the pink salmon prior to their release. Adult pink salmon from this experiment were captured in fisheries and also recovered from their natal Quinsam River, British Columbia. Pink salmon from each treatment group were recovered in similar numbers. Exposure of populations of fry to the WSF of crude oil and release to the Pacfic Ocean did not result in a detectable effect on their survival to maturity. Fry from all treatment groups incurred typically high mortality following release, and there were no discernible effects on survival that were attributable to exposure to the WSF of crude oil.

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