scholarly journals Spatio-temporal trends in the importance of iteroparity across Atlantic salmon populations of the northwest Atlantic

2019 ◽  
Author(s):  
X Bordeleau ◽  
S A Pardo ◽  
G Chaput ◽  
J April ◽  
B Dempson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Temporal Trends ◽  
High Variability ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Northwest Atlantic ◽  
Continental Scale ◽  
Spatio Temporal ◽  
Ecological Importance ◽  
Mixed Stock

AbstractIteroparity is a bet-hedging strategy where individuals spread the risk of reproductive failure over time. The occurrence of iteroparity (i.e. proportion of repeat spawners in annual returns) varies among Atlantic salmon (Salmo salar) populations, yet information on its ecological importance is limited. We compiled multi-decadal time series on the spawning history composition of Atlantic salmon annual returns across ten populations of the northwest Atlantic and West Greenland mixed-stock fishery landings to: (i) describe spatio-temporal patterns of iteroparity at the continental scale; (ii) quantify the reproductive contributions of repeat spawners; and (iii) test the hypothesis that iteroparity acts as a population safeguard during periods of low recruitment through repeat spawners’ contributions. Despite high variability in the representation of repeat spawners among populations and years (range: 0–24.7%; average: 5.0%), we identified broad-scale spatio-temporal shifts in iteroparity, with increases in mid-latitudinal and northern populations (from 3.1% to 7.6%) and declines in southern areas (from 4.1% to 2.7%), between the 1971–1992 and 1993–2017 periods. Our findings highlight the potential for increased prevalence of iteroparity when threats are mitigated (e.g. fishing pressure), with measurable benefits to population processes manifested by the high reproductive contributions of repeat spawners, especially in years of low maiden spawner abundance.

scholarly journals Costs and benefits of maternally inherited algal symbionts in coral larvae

2017 ◽  
Vol 284 (1857) ◽  
pp. 20170852 ◽  
Author(s):  
Valérie F. Chamberland ◽  
Kelly R. W. Latijnhouwers ◽  
Jef Huisman ◽  
Aaron C. Hartmann ◽  
Mark J. A. Vermeij
Keyword(s):  
Marine Invertebrates ◽  
Costs And Benefits ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Coral Larvae ◽  
Stony Coral ◽  
Algal Symbionts ◽  
Settlement Success ◽  
Spatio Temporal ◽  
Endosymbiotic Algae

Many marine invertebrates provide their offspring with symbionts. Yet the consequences of maternally inherited symbionts on larval fitness remain largely unexplored. In the stony coral Favia fragum (Esper 1797), mothers produce larvae with highly variable amounts of endosymbiotic algae, and we examined the implications of this variation in symbiont density on the performance of F. fragum larvae under different environmental scenarios. High symbiont densities prolonged the period that larvae actively swam and searched for suitable settlement habitats. Thermal stress reduced survival and settlement success in F. fragum larvae, whereby larvae with high symbiont densities suffered more from non-lethal stress and were five times more likely to die compared with larvae with low symbiont densities. These results show that maternally inherited algal symbionts can be either beneficial or harmful to coral larvae depending on the environmental conditions at hand, and suggest that F. fragum mothers use a bet-hedging strategy to minimize risks associated with spatio-temporal variability in their offspring's environment.

scholarly journals Provision of catch advice taking account of non-stationarity in productivity of Atlantic salmon (Salmo salar L.) in the Northwest Atlantic

2005 ◽  
Vol 62 (1) ◽  
pp. 131-143 ◽  
Author(s):  
G. Chaput ◽  
C.M. Legault ◽  
D.G. Reddin ◽  
F. Caron ◽  
P.G. Amiro
Keyword(s):  
Population Dynamics ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Model Prediction ◽  
Northwest Atlantic ◽  
Atlantic Salmon Salmo Salar ◽  
Parsimonious Models ◽  
Rate Of Decline ◽  
Management Advice ◽  
Mixed Stock

Abstract The paper presents the data, the models, and the approach for the provision of management advice for a high seas mixed stock fishery on Atlantic salmon (Salmo salar L.). The approach incorporates observation errors, model uncertainty, and considers a possible shift in the productivity of Atlantic salmon. The risk analysis framework further incorporates uncertainty in the fishery harvest characteristics and presents the catch advice as probabilities of meeting or exceeding the conservation objectives relative to catch options. There is very strong evidence from the analyses that there has been a phase shift in productivity of Atlantic salmon of North American origin in the Northwest Atlantic. The change in productivity likely resulted from a change in marine survival which occurred in the early 1990s and has persisted to date. When the uncertainties in the input data are considered, the most parsimonious models suggest that there has been a shift in absolute abundance independent of variations in the spawner index contributing to the recruitment. There continues to be a large amount of uncertainty in the measures of abundance and population dynamics of Atlantic salmon. Uncertainty in the understanding of population dynamics does not necessarily equate to uncertainty in management advice. If model results suggest that spawning objectives are unattainable even when harvest rates are zero, then any harvest level will either accelerate the rate of decline if the model prediction is correct or diminish the probability of recovery if the model prediction is wrong.

scholarly journals Genetic mixed stock analysis of an interceptory Atlantic salmon fishery in the Northwest Atlantic

2016 ◽  
Vol 174 ◽  
pp. 234-244 ◽  
Author(s):  
Ian R. Bradbury ◽  
Lorraine C. Hamilton ◽  
Gerald Chaput ◽  
Martha J. Robertson ◽  
Herlé Goraguer ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Northwest Atlantic ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock ◽  
Salmon Fishery

scholarly journals Mate choice for major histocompatibility complex genetic divergence as a bet-hedging strategy in the Atlantic salmon ( Salmo salar )

2011 ◽  
Vol 279 (1727) ◽  
pp. 379-386 ◽  
Author(s):  
Melissa L. Evans ◽  
Mélanie Dionne ◽  
Kristina M. Miller ◽  
Louis Bernatchez
Keyword(s):  
Major Histocompatibility Complex ◽  
Reproductive Success ◽  
Mate Choice ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Offspring Survival ◽  
Major Histocompatibility ◽  
Bet Hedging ◽  
Hedging Strategy ◽  
Histocompatibility Complex

Major histocompatibility complex (MHC)-dependent mating preferences have been observed across vertebrate taxa and these preferences are expected to promote offspring disease resistance and ultimately, viability. However, little empirical evidence linking MHC-dependent mate choice and fitness is available, particularly in wild populations. Here, we explore the adaptive potential of previously observed patterns of MHC-dependent mate choice in a wild population of Atlantic salmon ( Salmo salar ) in Québec, Canada, by examining the relationship between MHC genetic variation and adult reproductive success and offspring survival over 3 years of study. While Atlantic salmon choose their mates in order to increase MHC diversity in offspring, adult reproductive success was in fact maximized between pairs exhibiting an intermediate level of MHC dissimilarity. Moreover, patterns of offspring survival between years 0+ and 1+, and 1+ and 2+ and population genetic structure at the MHC locus relative to microsatellite loci indicate that strong temporal variation in selection is likely to be operating on the MHC. We interpret MHC-dependent mate choice for diversity as a likely bet-hedging strategy that maximizes parental fitness in the face of temporally variable and unpredictable natural selection pressures.

Genetic evidence of local exploitation of Atlantic salmon in a coastal subsistence fishery in the Northwest Atlantic

2015 ◽  
Vol 72 (1) ◽  
pp. 83-95 ◽  
Author(s):  
Ian R. Bradbury ◽  
Lorraine C. Hamilton ◽  
Sara Rafferty ◽  
David Meerburg ◽  
Rebecca Poole ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Genetic Analysis ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Northwest Atlantic ◽  
Western Atlantic ◽  
Individual Assignment ◽  
Salmon Fisheries ◽  
Mixed Stock ◽  
Migration Pathways

Fisheries targeting mixtures of populations risk the overutilization of minor stock constituents unless harvests are monitored and managed. We evaluated stock composition and exploitation of Atlantic salmon (Salmo salar) in a subsistence fishery in coastal Labrador, Canada, using genetic mixture analysis and individual assignment with a microsatellite baseline (15 loci, 11 829 individuals, 12 regional groups) encompassing the species’ western Atlantic range. Bayesian and maximum likelihood mixture analyses of fishery samples over 6 years (2006–2011; 1772 individuals) indicate contributions of adjacent stocks of 96%–97%. Estimates of fishery-associated exploitation were highest for Labrador salmon (4.2%–10.6% per year) and generally <1% for other regions. Individual assignment of fishery samples indicated nonlocal contributions to the fishery (e.g., Quebec, Newfoundland) were rare and primarily in southern Labrador, consistent with migration pathways utilizing the Strait of Belle Isle. This work illustrates how genetic analysis of mixed stock Atlantic salmon fisheries in the Northwest Atlantic using this new baseline can disentangle exploitation and reveal complex migratory behaviours.

Spatio-temporal trends and climatology of atmospheric chlorinated hydrocarbons over Pakistan

2021 ◽  
Vol 14 (15) ◽  
Author(s):  
Ahmad Hasnain ◽  
Yong Zha ◽  
Muhammad Zaffar Hashmi ◽  
Fatima Rahim ◽  
Yufeng He ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Chlorinated Hydrocarbons ◽  
Spatio Temporal

scholarly journals Individual reversible plasticity as a genotype‐level bet‐hedging strategy

2021 ◽  
Author(s):  
Thomas R. Haaland ◽  
Jonathan Wright ◽  
Irja I. Ratikainen
Keyword(s):  
Bet Hedging ◽  
Hedging Strategy

scholarly journals Spatio-temporal impacts of aerial adulticide applications on populations of West Nile virus vector mosquitoes

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karen M. Holcomb ◽  
Robert C. Reiner ◽  
Christopher M. Barker
Keyword(s):  
West Nile Virus ◽  
Temporal Trends ◽  
Larval Habitat ◽  
Post Treatment ◽  
Additive Models ◽  
Dispersal Ability ◽  
Stochastic Variation ◽  
West Nile ◽  
Spatial Coverage ◽  
Spatio Temporal

Abstract Background Aerial applications of insecticides that target adult mosquitoes are widely used to reduce transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of the reduction in abundance following these treatments typically focus on single events, rely on pre-defined, untreated control sites and can vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment. Methods To overcome these limitations, we developed generalized additive models fitted to mosquito surveillance data collected from CO2-baited traps in Sacramento and Yolo counties, California from 2006 to 2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex (Cx.) tarsalis and Cx. pipiens in the absence of aerial spraying. Estimates for the magnitude of deviation from baseline abundance following aerial spray events were obtained from the models. Results At 1-week post-treatment with full spatial coverage of the trapping area by pyrethroid or pyrethrin products, Cx. pipiens abundance was reduced by a mean of 52.4% (95% confidence intrval [CI] − 65.6, − 36.5%) while the use of at least one organophosphate pesticide resulted in a mean reduction of 76.2% (95% CI − 82.8, − 67.9%). For Cx. tarsalis, at 1-week post-treatment with full coverage there was a reduction in abundance of 30.7% (95% CI − 54.5, 2.5%). Pesticide class was not a significant factor contributing to the reduction. In comparison, repetition of spraying over three to four consecutive weeks resulted in similar estimates for Cx. pipiens and estimates of somewhat smaller magnitude for Cx. tarsalis. Conclusions Aerial adulticides are effective for achieving a rapid short-term reduction of the abundance of the primary West Nile virus vectors, Cx. tarsalis and Cx. pipiens. A larger magnitude of reduction was estimated in Cx. pipiens, possibly due to the species’ focal distribution. Effects of aerial sprays on Cx. tarsalis populations are likely modulated by the species’ large dispersal ability, population sizes and vast productive larval habitat present in the study area. Our modeling approach provides a new way to estimate effects of public health pesticides on vector populations using routinely collected observational data and accounting for spatio-temporal trends and contextual factors like weather and habitat. This approach does not require pre-selected control sites and expands upon past studies that have focused on the effects of individual aerial treatment events.

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