Pacific Salmon Environmental and Life History Models: Advancing Science for Sustainable Salmon in the Future

2009 ◽  
Keyword(s):  
Life History ◽  
Simulation Model ◽  
Fishery Management ◽  
Management Practices ◽  
Oncorhynchus Tshawytscha ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Pacific Salmon ◽  
Ricker Model ◽  
Marine Environmental

<em>Abstract.</em>—This study demonstrates an application of a life history simulation model to evaluate robustness of a spawner-recruit model and fishery management practices. A Chinook salmon <em>Oncorhynchus tshawytscha </em>life history simulation model was constructed with inclusion of various density-dependent conditions, marine environmental changes, and marine derived nutrients (MDN). The simulation model was run for 200 years. At the 101st year, a fishery was introduced at harvest rates of 25, 50, or 75%. The Ricker spawner-recruit model was fit to data from pre-fishery (1–100th) and post-fishery (181–200th) years. The Ricker model parameters (<em>α</em>, <em>β</em>), equilibrium spawner size (<em>S<sub>k</sub></em>), and spawner population size that provides the maximum sustainable yield (<em>S<sub>msy</sub></em>) were estimated, and compared between pre-fishery and post-fishery. In addition, “true” <em>S<sub>k</sub> </em>and <em>S<sub>msy</sub> </em>were calculated directly from the life history model and were compared with those estimated by the Ricker-model. Results showed that: 1) the pre-fishery Ricker model <em>S<sub>msy</sub> </em>estimates tended to be about the same or higher than the “true” <em>S<sub>msy</sub></em>, but lower than those with MDN effects, 2) the post-fishery Ricker model <em>S<sub>msy</sub> </em>estimates tended to be lower than the pre-fishery ones and “true” <em>S<sub>msy</sub></em>, especially at the 50% and 75% harvest rates, and 3) the above results did not differ largely with inclusion of marine environmental variability in the model. These results suggest that the Ricker model is sufficiently robust to fit and estimate <em>S<sub>msy</sub> </em>for various populations except for those with MDN effects, and only when it was fit to pre-fishery (unexploited) and/or low harvest rate data. However, for populations with high harvest rates, the Ricker model tends to underestimate <em>S<sub>k</sub> </em>and <em>S<sub>msy</sub></em>.

Pacific Salmon Environmental and Life History Models: Advancing Science for Sustainable Salmon in the Future

2009 ◽  
Keyword(s):  
Life History ◽  
Iterative Process ◽  
Human Population ◽  
Habitat Restoration ◽  
Oncorhynchus Tshawytscha ◽  
Habitat Degradation ◽  
Pacific Salmon ◽  
Puget Sound ◽  
Habitat Conditions ◽  
Restoration And Protection

<em>Abstract.</em>—The Washington Department of Fish and Wildlife and Tribal co-managers are using the Ecosystem Diagnosis and Treatment (EDT) model to identify the spatial and temporal habitat limits of salmon populations and predict the effects of proposed habitat restoration projects for ESA-listed Chinook salmon <em>Oncorhynchus tshawytscha </em>in two Puget Sound watersheds. The collaborative, iterative process focused on habitat-based population models for the Dungeness and Dosewallips watersheds. Workshops were held to develop quantitative characteristics of current, historic, hypothetical properly functioning, and future habitat conditions. The model predicted salmon populations in the watersheds for each set of habitat conditions. Recovery targets were based on the predicted populations for historic and hypothetical properly functioning conditions. Future populations were modeled using projected habitat conditions with individual habitat restoration and protection actions already proposed and combinations of these actions. Populations resulting from further habitat degradation were estimated using the effects of projected human population growth on habitat.

Rates of straying by hatchery-produced Pacific salmon (Oncorhynchus spp.) and steelhead (Oncorhynchus mykiss) differ among species, life history types, and populations

2013 ◽  
Vol 70 (5) ◽  
pp. 735-746 ◽  
Author(s):  
Peter A.H. Westley ◽  
Thomas P. Quinn ◽  
Andrew H. Dittman
Keyword(s):  
Life History ◽  
Oncorhynchus Mykiss ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Upstream Migration ◽  
Endocrine Factors ◽  
Species Specific ◽  
Stream Type

Here we ask whether straying differs among species, life history types, and populations of adult hatchery-produced Pacific salmon (Oncorhynchus spp.) and steelhead (Oncorhynchus mykiss) in the Columbia River basin. Previous estimates of straying have been confounded by various factors influencing the probability of individuals returning to non-natal sites (e.g., off-station releases), whereas analyses undertaken here of nearly a quarter million coded-wire tag recoveries control for these factors. Our results revealed large and generally consistent differences in the propensity to stray among species, life history types within species, and populations. Paired releases indicated that (i) Chinook salmon (Oncorhynchus tshawytscha) strayed more (mean population range 0.11%–34.6%) than coho salmon (Oncorhynchus kisutch) (0.08%–0.94%); (ii) ocean-type Chinook (5.2%–18.6%) strayed more than stream-type Chinook (0.11%–10%); and Chinook salmon (0.90%–54.9%) strayed more than steelhead (0.30%–2.3%). We conclude these patterns are largely the result of species-specific behavioral and endocrine factors during the juvenile life stages, but analyses also suggest that environmental factors can influence straying during the adult upstream migration.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals Life history, climate and biogeography interactively affect worldwide genetic diversity of plant and animal populations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
H. De Kort ◽  
J. G. Prunier ◽  
S. Ducatez ◽  
O. Honnay ◽  
M. Baguette ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Life History ◽  
Evolutionary Dynamics ◽  
Environmental Changes ◽  
Peripheral Populations ◽  
Plant Dispersal ◽  
Weak Support ◽  
Animal Populations ◽  
Plant Groups ◽  
Conservation Genetic

AbstractUnderstanding how biological and environmental factors interactively shape the global distribution of plant and animal genetic diversity is fundamental to biodiversity conservation. Genetic diversity measured in local populations (GDP) is correspondingly assumed representative for population fitness and eco-evolutionary dynamics. For 8356 populations across the globe, we report that plants systematically display much lower GDP than animals, and that life history traits shape GDP patterns both directly (animal longevity and size), and indirectly by mediating core-periphery patterns (animal fecundity and plant dispersal). Particularly in some plant groups, peripheral populations can sustain similar GDP as core populations, emphasizing their potential conservation value. We further find surprisingly weak support for general latitudinal GDP trends. Finally, contemporary rather than past climate contributes to the spatial distribution of GDP, suggesting that contemporary environmental changes affect global patterns of GDP. Our findings generate new perspectives for the conservation of genetic resources at worldwide and taxonomic-wide scales.

Play it Again Sam — an Essay on Salmon Enhancement

1974 ◽  
Vol 31 (8) ◽  
pp. 1433-1456 ◽  
Author(s):  
P. A. Larkin
Keyword(s):  
Management Practices ◽  
Pacific Salmon ◽  
Point Of View ◽  
Provincial Government ◽  
Research Information ◽  
Control Programs ◽  
Successful Program ◽  
The Pacific ◽  
Management And Development ◽  
Economic Worth

For more than 100 years efforts have been made to increase the abundance of the various species of Pacific salmon. The success of these ventures is largely a matter of conjecture because the scale of natural fluctuations is sufficient to mask the effect of human intervention. No well-defined program for salmon enhancement has yet been developed for British Columbia as a whole. This is mainly attributable to the pressures for providing protection for the existing stocks in the circumstances of an intensive fishery and increasing effects of other resource uses.From a social point of view, salmon enhancement is a highly desirable activity. Salmon occupy a special place in the culture of residents of the Pacific coast. Salmon arc economically valuable and salmon fishing provides a rich source of employment. Recreational fisheries are valuable but their true economic worth is difficult to judge. Benefit:cost ratios for salmon enhancement should be calculated for whole programs rather than for individual projects to obtain an approach consistent with the desirable strategy of development.From a biological point of view, salmon enhancement is feasible. There is potential in the ocean for growing more salmon; many historic runs can be rebuilt and there are many opportunities for colonizing watersheds that are currently inaccessible to salmon. Harvesting of increased stocks of salmon could pose risks for natural stocks that are relatively unproductive. More effective management and development of new strains of salmon may be required in these circumstances. Predator-control programs may in some instances be useful adjuncts to salmon-enhancement projects.The types of enhancement activity that will most likely be rewarding are those that interfere least with the natural life history. Removal of obstructions, regulation of stream flow, construction of artificial spawning channels, are typical simple measures that involve less research information and less risk than rearing hatcheries.Priorities for different salmon-enhancement projects involve consideration of the regional economic and social conditions as well as appreciation of the biological and physical problems. Regardless of priorities it is essential to a successful program that there be a commitment to continuity. Additionally, the total administrative complex for salmon enhancement should involve research components.The execution of a successful salmon-enhancement program depends on the establishment of an agency with the single responsibility of salmon enhancement. The financing of a successful program should depend partly on revenues generated from the resource users, such as a tax on commercially caught salmon, a license for saltwater angling. Special grants from federal and provincial governments would also be appropriate. Regardless of the administrative arrangements, it is urgently necessary that provincial government involvement be more substantial than it is at present. With their control over resource management practices, the provincial government is in a vital position for maintenance of freshwater environments.An investment of at least $100 million, and probably twice that amount, could be undertaken in a salmon-enhancement program that could be executed within 10 years. There are compelling reasons for starting on this enhancement program immediately.

scholarly journals Climate change drives mountain butterflies towards the summits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dennis Rödder ◽  
Thomas Schmitt ◽  
Patrick Gros ◽  
Werner Ulrich ◽  
Jan Christian Habel
Keyword(s):  
Climate Change ◽  
Life History ◽  
Climate Warming ◽  
Environmental Changes ◽  
Range Shifts ◽  
Solar Irradiation ◽  
High Mountain ◽  
Detailed Knowledge ◽  
Annual Range

AbstractClimate change impacts biodiversity and is driving range shifts of species and populations across the globe. To understand the effects of climate warming on biota, long-term observations of the occurrence of species and detailed knowledge on their ecology and life-history is crucial. Mountain species particularly suffer under climate warming and often respond to environmental changes by altitudinal range shifts. We assessed long-term distribution trends of mountain butterflies across the eastern Alps and calculated species’ specific annual range shifts based on field observations and species distribution models, counterbalancing the potential drawbacks of both approaches. We also compiled details on the ecology, behaviour and life-history, and the climate niche of each species assessed. We found that the highest altitudinal maxima were observed recently in the majority of cases, while the lowest altitudes of observations were recorded before 1980. Mobile and generalist species with a broad ecological amplitude tended to move uphill more than specialist and sedentary species. As main drivers we identified climatic conditions and topographic variables, such as insolation and solar irradiation. This study provides important evidence for responses of high mountain taxa to rapid climate change. Our study underlines the advantage of combining historical surveys and museum collection data with cutting-edge analyses.

scholarly journals A Scoping Review of Organizational Responses to the COVID-19 Pandemic in Schools: A Complex Systems Perspective

2021 ◽  
Vol 11 (3) ◽  
pp. 115
Author(s):  
Puspa Khanal ◽  
Fabio Bento ◽  
Marco Tagliabue
Keyword(s):  
Scoping Review ◽  
Management Practices ◽  
Environmental Changes ◽  
Research Literature ◽  
Organizational Adaptation ◽  
Open Communication ◽  
Organizational Responses ◽  
Additional Element ◽  
Systems Perspective ◽  
School Settings

This study is a scoping review of the literature on organizational adaptation in school settings during the early stages of the COVID-19 pandemic. Dramatic and unexpected environmental changes raise questions about the capacity of schooling organizations to adapt to in response to the pandemic. Different management practices have implications for the selection of organizational behaviors, electively in school settings. The research literature on school responses is analyzed from a selectionist perspective. The aim of this study is to identify and describe three constituting elements of this perspective: variation, interaction, and selection. An additional element is considered in this analysis and comprises the mechanisms of exploration and exploitation in the context of organizational adaptation. Sixteen studies met the selection criteria of describing emergent processes in schools. The findings highlight the emergence of exploration, as teachers actively experimented with a range of strategies and methods in order to maintain educational activities in the complex and uncertain context of the COVID-19 pandemic. However, several questions are raised regarding the effects and maintenance of new practices in the post-pandemic scenario. Management practices that facilitate variation and open communication about learning processes can contribute to the process of organizational adaptation.

Climate and environmental context of the Mongol invasion of Syria and defeat at ‘Ayn Jālūt (1258–1260 CE)

Erdkunde ◽  
2021 ◽  
Vol 75 (2) ◽  
pp. 87-104
Author(s):  
Nicola Di Cosmo ◽  
Sebastian Wagner ◽  
Ulf Büntgen
Keyword(s):  
Strategic Alliances ◽  
Turning Point ◽  
Environmental Changes ◽  
Environmental Variability ◽  
State Of The Art ◽  
Eastern Mediterranean ◽  
The Caucasus ◽  
Mountainous Regions ◽  
The Past ◽  
Climate Reconstructions

After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.

scholarly journals Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Time Lag ◽  
Cyanobacteria Blooms ◽  
Environment Variables ◽  
Sampling Points ◽  
The Relationship

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

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