Potential Usefulness of Chlorine for Controlling Pacific Salmon Leeches, Piscicola salmositica, in Hatcheries

1985 ◽  
Vol 42 (12) ◽  
pp. 1986-1993 ◽  
Author(s):  
S. M. Bower ◽  
L. Margolis ◽  
R. J. MacKay
Keyword(s):  
Logistic Regression Model ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Juvenile Fish ◽  
Gill Tissue ◽  
Residual Chlorine ◽  
Lethal Effects ◽  
Small Juvenile ◽  
Wide Range ◽  
Low Levels

Susceptibility to the lethal effects of low levels of total residual chlorine (TRC) differed between juvenile coho salmon (Oncorhynchus kisutch) and the salmon leech (Piscicola salmositica), the vector for the haemoflagellate salmonid pathogen Cryptobia salmositica. There was no salmon mortality at concentrations below approximately 50 μg TRC/L for the maximum exposure time of 24 h. Some damage to gill tissue (hypertrophy, fusion, oedema, and some necrosis), was observed at the highest concentrations of TRC that did not kill any of the fish (approximately 50 μg/L for 24 h, and approximately 100 μg/L for 8 h). This damage was repaired by the fish within 4 d of exposure, although evidence of past irritation was noted in 6 of 12 fish. All small juvenile leeches exposed to 44 μg TRC/L for 24 h died, and over half of such leeches exposed to 44 μg/L for 8 h and 21 μg/L for 24 h died. Below TRC concentrations that were lethal to the fish (approximately 50 μg/L), contours of constant leech mortality derived from a logistic regression model fitted to the data offered a wide range of concentrations and exposure times that would result in high mortality of juvenile leeches. Larger subadult and adult leeches were more resistant to chlorine than the smaller leeches but were more sensitive than the juvenile fish. Thus, chlorine may prove useful for controlling P. salmositica in salmonid hatcheries.

Selection for Adult Size in Female Coho Salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 43 (10) ◽  
pp. 1946-1959 ◽  
Author(s):  
L B. Holtby ◽  
M. C. Healey
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Selective Advantage ◽  
Evolutionary Stable Strategy ◽  
Relative Fitness ◽  
Female Size ◽  
Adult Size ◽  
Stable Strategy ◽  
Wide Range

Several recent studies have presented evidence that large size confers a selective advantage to female Pacific salmon. Nevertheless, a wide range of female sizes is normally present in any spawning population. Two possible explanations exist for the observed range in female size. First, average female size might be determined by an optimizing process with variation around the optimum size due to individual differences in success at obtaining food. Second, various sizes of females might coexist as a mixed evolutionary stable strategy. Under the first explanation, females of sizes other than the optimum would display lower fitness whereas, under the second explanation, females of all sizes would be equally fit. We investigated factors affecting survival of eggs, fry, and smolts of coho salmon (Oncorhynchus kisutch) in Carnation Creek on Vancouver Island with a view to determining the relative fitness of different sized females. Egg-to-fry mortality was best explained by a model that included only the effects of stream bed scour and gravel quality. Including an effect of female size, expressed through depth of egg burying, worsened the model's predictive capability. We could find no evidence that the eggs of large females consistently survived better during incubation than those of small females. In fact, we observed three instances in which it appeared that the eggs of small females survived better. In Carnation Creek, large 1- and 2-yr-old smolts did not consistently survive better in the marine environment than small smolts. Thus, we were unable to demonstrate that the reproductive success of large females was consistently higher than that of small females, contrary to the hypothesis that female size is the result of an optimizing process. In Carnation Creek the observed range of female sizes probably represents an evolutionary stable strategy in which all sizes have equal fitness. We propose a model that predicts female size and variance in size based on the conflicting selective effects of gravel quality, scour, and competition for nest sites.

scholarly journals Genetically enhanced growth causes increased mortality in hypoxic environments

2007 ◽  
Vol 3 (2) ◽  
pp. 165-168 ◽  
Author(s):  
L Sundt-Hansen ◽  
L.F Sundström ◽  
S Einum ◽  
K Hindar ◽  
I.A Fleming ◽  
...  
Keyword(s):  
Larval Stage ◽  
Rapid Growth ◽  
Coho Salmon ◽  
Survival Rates ◽  
Limiting Factor ◽  
Low Oxygen ◽  
Wide Range ◽  
Survival And Development ◽  
Survival And Growth ◽  
Low Levels

Rapid growth and development are associated with several fitness-related benefits. Yet, organisms usually grow more slowly than their physiological maximum, suggesting that rapid growth may carry costs. Here we use coho salmon ( Oncorhynchus kisutch ) eggs of wild and transgenic genotypes to test whether rapid growth causes reduced tolerance to low levels of oxygen (hypoxia). Eggs were exposed to four different durations of hypoxia, and survival and growth were recorded until the end of the larval stage. Survival rates decreased with increasing duration of hypoxia, but this decrease was most pronounced for the transgenic group. Larval mass was also negatively affected by hypoxia; however, transgenic genotypes were significantly larger than wild genotypes at the end of the larval stage. Oxygen can be a limiting factor for survival and development in a wide range of organisms, particularly during the egg stage. Thus, the reduced ability of fast-growing genotypes to cope with low oxygen levels identified in the present study may represent a general constraint on evolution of rapid growth across taxa.

Evaluation of visual survey methods for monitoring Pacific salmon (Oncorhynchus spp.) escapement in relation to conservation guidelines

2008 ◽  
Vol 65 (2) ◽  
pp. 212-226 ◽  
Author(s):  
Kendra R Holt ◽  
Sean P Cox
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Survey Methods ◽  
Effective Means ◽  
Area Under The Curve ◽  
Cost Effective ◽  
Trend Detection ◽  
Conservation Units ◽  
Visual Survey ◽  
Wide Range

Canada’s Wild Salmon Policy requires that biological status of conservation units of Pacific salmon (Oncorhynchus spp.) be assessed regularly in relation to abundance-based benchmarks. Visual survey methods, in which periodic counts of spawning fish are made throughout a season, will likely be used for this purpose because they provide a cost-effective means of monitoring interannual trends in escapement. Trend detection performance for visual survey methods depends mainly upon consistency in (i) the ability of observers to detect fish and (ii) the annual timing of fish presence in the survey area. We developed a Monte Carlo simulation procedure to evaluate the ability of four visual survey methods (peak count, mean count, trapezoidal area-under-the-curve (AUC), and likelihood AUC) to detect 30% declines in coho salmon (Oncorhynchus kisutch) escapement over 10 years (i.e., the magnitude of trend that would warrant listing a coho population as threatened using the listing criteria of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC)) given realistic levels of variability in these two factors. The mean count outperformed all other approaches across a wide range of scenarios about true population dynamics and survey designs, suggesting that a simple mean count method is suitable for monitoring coho escapements in relation to COSEWIC guidelines.

Assessing developmental errors in branchiostegal rays as indicators of chronic stress in two species of Pacific salmon

2003 ◽  
Vol 81 (11) ◽  
pp. 1876-1884 ◽  
Author(s):  
W Bruce Campbell
Keyword(s):  
Kidney Disease ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Linear Models ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Ambient Temperatures ◽  
Bacterial Kidney Disease ◽  
Significant Difference ◽  
Low Levels

Stress during ontogeny reduces homeostasis, increasing the formation of developmental errors. Fused and partial branchiostegal rays were assessed as indicators of stress throughout embryogenesis in coho salmon (Oncorhy nchus kisutch Walbaum) and chinook salmon (Oncorhynchus tshawytscha Walbaum). Error frequencies and the proportion of fish possessing them should increase when development is stressed. Coho parr were examined from reciprocal crosses between two hatchery stocks experiencing artificially fluctuated (between 7 and 12 °C) or ambient (natural) temperatures throughout embryogenesis. Temperature means and ranges were equivalent between treatments, allowing patterns of thermal variance to be compared. Chinook presmolts, having high versus low levels of infection with bacterial kidney disease owing to similar levels of parental infection, also were examined. Sampled fish were cleared and stained and the errors analyzed using categorical linear models and observations of positional distributions. Although partial rays in coho were genetically influenced, fusion frequency increased significantly under fluctuating (551) versus ambient temperatures (163), as did the number of fish with fusions (207 versus 104, respectively). No significant difference between bacterial kidney disease groups was observed, indicating the disease had little influence over error development. Positional distributions of fused rays were bimodal in both species, showing anterior and posterior zones of weaker developmental control. Partial rays occurred at initial and terminal positions in the series, suggesting evolutionary vestigialization in both species. Branchiostegal ray fusions are shown to be useful traits for further investigation of thermal stress during embryogenesis in salmon.

scholarly journals Acceptance threshold theory can explain occurrence of homosexual behaviour

2015 ◽  
Vol 11 (1) ◽  
pp. 20140603 ◽  
Author(s):  
Katharina C. Engel ◽  
Lisa Männer ◽  
Manfred Ayasse ◽  
Sandra Steiger
Keyword(s):  
Animal Species ◽  
Reproductive Potential ◽  
Search Time ◽  
Same Sex ◽  
Burying Beetles ◽  
Acceptance Threshold ◽  
Threshold Theory ◽  
Wide Range ◽  
Low Levels ◽  
Perceived Costs

Same-sex sexual behaviour (SSB) has been documented in a wide range of animals, but its evolutionary causes are not well understood. Here, we investigated SSB in the light of Reeve's acceptance threshold theory. When recognition is not error-proof, the acceptance threshold used by males to recognize potential mating partners should be flexibly adjusted to maximize the fitness pay-off between the costs of erroneously accepting males and the benefits of accepting females. By manipulating male burying beetles' search time for females and their reproductive potential, we influenced their perceived costs of making an acceptance or rejection error. As predicted, when the costs of rejecting females increased, males exhibited more permissive discrimination decisions and showed high levels of SSB; when the costs of accepting males increased, males were more restrictive and showed low levels of SSB. Our results support the idea that in animal species, in which the recognition cues of females and males overlap to a certain degree, SSB is a consequence of an adaptive discrimination strategy to avoid the costs of making rejection errors.

Violencia en el hogar contra mujeres adultas durante el confinamiento por la pandemia de Covid-19 en México

2021 ◽  
Vol 63 (6, Nov-Dic) ◽  
pp. 782-788
Author(s):  
Rosario Valdez-Santiago ◽  
Aremis Litai Villalobos-Hernández ◽  
Luz Arenas-Monreal ◽  
Karla Flores ◽  
Luciana Ramos-Lira
Keyword(s):  
Domestic Violence ◽  
Logistic Regression ◽  
Associated Factors ◽  
Logistic Regression Model ◽  
Well Being ◽  
Adult Women ◽  
Nutrition Survey ◽  
Health And Nutrition ◽  
National Representation ◽  
Low Levels

Objective. To analyze the prevalence of domestic violence in adult women during confinement derived from the Co­vid-19 pandemic and individual, familiar and communitarian associated factors. Materials and methods. A second­ary analysis was carried out the 2020 National Health and Nutrition Survey on Covid-19, with national representation. A logistic regression model adjusted for the variables of interest was performed. Results. The prevalence was 5.8%. The most reported acts were shouting, insults or threats (4.3%). Most of the women who reported some type of violence in the home had already experienced it before the confinement. Low levels of well-being (OR= 1.96, 95%CI: 1.28,2.99), and living in a home where job was lost due to contingency (OR= 1.96, 95%CI: 1.41,2.73) were associated factors. Conclusions. In care interventions, it is necessary to take into account factors that deepen the vulnerability of women, such as pre-existing violence and loss of employment.

MUSCLE PROTEINS OF PACIFIC SALMON (ONCORHYNCHUS): II. AN INVESTIGATION OF MUSCLE PROTEIN AND OTHER SUBSTANCES SOLUBLE IN SALT SOLUTIONS OF LOW IONIC STRENGTH BY COLUMN CHROMATOGRAPHY

1962 ◽  
Vol 40 (7) ◽  
pp. 919-927 ◽  
Author(s):  
H. Tsuyuki ◽  
E. Roberts ◽  
R. E. A. Gadd
Keyword(s):  
Sockeye Salmon ◽  
Moving Boundary ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Muscle Protein ◽  
Deae Cellulose ◽  
Ophiodon Elongatus ◽  
The Pacific ◽  
Other Substances ◽  
Low Ionic Strength

The muscle myogens and other components of the spring salmon (O. tshawytscha), chum salmon (O. keta), coho salmon (O. kisutch), and sockeye salmon (O. nerka), as well as the lingcod (Ophiodon elongatus), were separated by the use of diethylaminoethyl (DEAE) cellulose columns. Significant amounts of slowly dialyzable inosine and inosinic acid which may lead to spurious peaks in moving-boundary electrophoretic separations have been shown to be present in the muscle myogen preparations. The basic differences in the muscle myogen components of the Pacific salmon and the lingcod are compared.

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.

Inhibitory effects of catecholamines in canine cardiac Purkinje fibers

1976 ◽  
Vol 231 (5) ◽  
pp. 1415-1420 ◽  
Author(s):  
P Posner ◽  
EL Farrar ◽  
CR Lambert
Keyword(s):  
Negative Response ◽  
Chronotropic Effect ◽  
Inhibitory Effects ◽  
Purkinje Fibers ◽  
Spontaneous Rate ◽  
Negative Chronotropic Effect ◽  
Cardiac Purkinje Fibers ◽  
Wide Range ◽  
Low Levels

The effect of catecholamines over a wide range of concentrations was studied on 42K uptake and efflux, as well as on spontaneous rate in canine cardiac Purkinje fibers. Low levels of catecholamines (less than 10(-10) M epinephrine; less than 10(-9) M norepinephrine) decreased automaticity. This negative chronotropic effect was blocked by phentolamine and mimicked by phenylephrine. These low levels of epinephrine and norepinephrine also inhibited 42K uptake by Purkinje fibers but had no effect on 42K efflux. The inhibition of 42K uptake was blocked by phentolamine and verapamil and mimicked by phenylephrine. The data indicate an alpha-receptor-mediated negative response of rate and 42K uptake to low levels of catecholamine. The end result is discussed in terms of a competitive increase in the influx of Ca2+ rather than Na+ and an indirect inhibition of the Na+-K+ pump.

Breeding and Mating Systems of Australian Proteaceae

1998 ◽  
Vol 46 (4) ◽  
pp. 421 ◽  
Author(s):  
Ross L. Goldingay ◽  
Susan M. Carthew
Keyword(s):  
Fruit Development ◽  
Mating Systems ◽  
Pollen Deposition ◽  
Genetic Studies ◽  
The Past ◽  
Wide Range ◽  
The Family ◽  
Self Compatibility ◽  
Low Levels ◽  
Key Events

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.

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