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Facilitation of fisheries by natural predators
Facilitation of fisheries by natural predators

... prey (subdivided into two populations to be able to vary the overlap in resource use). We assume that resource productivity is constant and hence independent of resource density (Supplementary material Appendix 1 Table A1.3). Resource densities decrease following consumption, which, in turn, decreas ...
The road toward sympatric speciation in whitefish.
The road toward sympatric speciation in whitefish.

... For almost every organism there are large gaps in our knowledge about the processes that leads to speciation. The changes an organism undergoes before divergence has occurred have remained a mystery, as it is difficult to say whether or not a species is going to diverge and when. To investigate this ...
Ten Steps to Responsible Inland Fisheries
Ten Steps to Responsible Inland Fisheries

... »» Establish fishery and water management plans that include maintenance of an adequate and diverse supply of nutrient rich aquatic products. ...
Mechanistic Approaches to Community Ecology
Mechanistic Approaches to Community Ecology

... which interpret community ecology almost strictly in terms of "megaparameters." Mechanistic approaches can be divided into those which use population dynamics as a major component of the theory and those which do not; examples of the two are about equally common. The first approach sacrifices a high ...
garter snake population dynamics from a 16
garter snake population dynamics from a 16

... cators for certain environmental toxins (Stafford et al. 1976, Olendorf 1988). However, in order to use snake populations as metrics of ecological trends, we need to better understand how sampling effort and design can impact our ability to derive appropriate and precise demographic models. Much of ...
RESEARCH REPORT Synopsis of 50 Years of Warmwater Fish STATE OF MICHIGAN
RESEARCH REPORT Synopsis of 50 Years of Warmwater Fish STATE OF MICHIGAN

... probably occurred through increased recruitment of small fish to the populations, but there is no measure of that. Population studies on the slow-growing bluegill began in 1957 (Patriarche 1968). Estimates of all important species were made by size groups in 1958 (Patriarche 1961b) and are believed ...
Determining selection across heterogeneous
Determining selection across heterogeneous

... reaction-diffusion dynamics. The approach rests on the assumption in adaptive dynamics that single mutations have small phenotypic effects. Hence, the selection gradient is essentially describing first order, or weak, selection. This is not in itself a new approach (especially for matrix models, see ...
Multispecies advice
Multispecies advice

... Figure 8.3.3.2 presents the main results of the SMS model updated and reviewed at the ICES Workshop on Baltic Multispecies (WKMULTBAL) in 2012 (ICES, 2012a) and presented in WKBALT in 2013 with updates of data from the benchmark. For more specific model settings please look at WKBALT 2013 (ICES, 201 ...
Vancouver Island Marmot Population and Habitat Viability
Vancouver Island Marmot Population and Habitat Viability

... The Vancouver Island marmot (Marmota vancouverensis) is the rarest of the six species of marmot found in North America and is limited to the more mountainous regions of Vancouver Island, British Columbia, Canada. Its closest relatives are the Olympic marmot (M. olympus) of the Olympic Peninsula, Uni ...
Larval ecology of an ascidian tropical population in a Mediterranean
Larval ecology of an ascidian tropical population in a Mediterranean

... Salinity was constant between 39 and 40%0and the only parameter that behaved somewhat irregularly was water temperature, which dropped below 22°C during July (Fig. 3 ) . The granulometric study and the organic material content showed that the edges along the bottom are composed mainly of coarse sand ...
Population dynamics in a cyclic environment: consequences of
Population dynamics in a cyclic environment: consequences of

... 1. Understanding which factors regulate population dynamics may help us to understand how a population would respond to environmental change, and why some populations are declining. 2. In southern Finland, vole abundance shows a three-phased cycle of low, increase and decrease phases, but these have ...
Density dependence in mule deer
Density dependence in mule deer

... the major differences between different theoretical population growth models are often manifest when populations are below carrying capacity, with each model having a different set of ecological circumstances under which it is most useful, any single mathematical function is of nominal consequence to t ...
Fisheries Ecology
Fisheries Ecology

... concepts and quantitative models needed to successfully reviews in fish biolgy and fisheries, wiley marine fisheries ecology simon jennings michel - preface ix acknowledgements xii 1 marine fisheries ecology an introduction 1 1 1 introduction 1 1 2 fisheries of the world 1 1 2 1 history of fisheries ...
CBD
CBD

... flexible Integral Population Model approach (see the book by Kery and Schaub, Bayesian Population Analysis Using WinBugs). In 2016, the first empirical results from the Daphnia experimental system set up by Professor Sigurd Einum appeared. This system is excellent for parameterizing models describin ...
Exploring the Status of Population Genetics: The Role of Ecology
Exploring the Status of Population Genetics: The Role of Ecology

... Sheppard (1950, 1954), and the studies of Panaxia dominula (scarlet tiger moth) by Fisher and Ford (1947). However, there are a number of other, equally wellknown studies during this time period that are not part of the Fordian tradition but that fit Ford’s characterization of ecological genetics. T ...
The Northern Abalone
The Northern Abalone

... The first people of Haida Gwaii have several names for abalone depending upon dialect, among them galgaahliiyaang and galguuhlkyan. In Haida legend, it is said that the northern abalone descended from the northwestern toad during the “Time of the Raven”. For thousands of years, the Haida harvested n ...
Management plan in Estonia
Management plan in Estonia

... populations and increasing of food basis for scavenger species. The biggest dangers to Estonian large carnivores are over-hunting, potentially negative public opinion and in the case of bear also disturbance. As of habitat quality, influence of decreasing roe-deer population on lynx and potential be ...
Issues of Elk Productivity for Research and
Issues of Elk Productivity for Research and

... regulation evidently was caused by intraspecific competition for food that decreased reproductive performance, increased juvenile mortality rates, and in some cases increased adult mortality rates. Density dependent changes in vital rates were most obvious in ungulates when populations are close to ...
File - Links Biology Website
File - Links Biology Website

... Describe the factors that affect population density. Identify when a population is growing or decreasing Look at a graph determine if it is exponential or logistic Describe the differences between exponential growth and logistic growth What is ecology? How much energy is lost from trophic level to t ...
Do delayed effects of overgrazing explain population cycles in voles?
Do delayed effects of overgrazing explain population cycles in voles?

... Theoretical models predict that delayed density-dependent processes with a time-lag of approximately nine months are sufficient to generate regular 3 – 5 year fluctuations in densities of northern small rodents. To examine whether this time-lag could be generated by plant-herbivore interactions, we ...
effects of ration size and temperature on moult increment and
effects of ration size and temperature on moult increment and

... metabolic parameters of 80 juvenile noble crayfish (Astacus astacus). The maximum daily consumption (Cmax) and respiration rate (R) were used to calculate the growth scope (i.e. the difference between maximum daily energy consumption and energy costs at a given temperature). The conversion of R into ...
What is an apex predator?
What is an apex predator?

... Large ‘apex’ predators influence ecosystems in profound ways, by limiting the density of their prey and controlling smaller ‘mesopredators’. The loss of apex predators from much of their range has lead to a global outbreak of mesopredators, a process known as ‘mesopredator release’ that increases pre ...
A simple predator–prey model of exploited
A simple predator–prey model of exploited

... predator. Each of these cases is discussed below. Prey is harvested, predator is not harvested. This situation was analyzed by Collie and Spencer (1994) for the case where B=1; allowing 0
Revisiting Carrying Capacity: Area-Based Indicators of Sustainability
Revisiting Carrying Capacity: Area-Based Indicators of Sustainability

... mainstream (neoclassical) models are blind to ecological structure and function, they cannot even properly address this question. The present article therefore assesses the capital stocks, physical flows, and corresponding ecosystems areas required to support the economy using "ecological footprint" ...
Exploring the Status of Population Genetics: The Role of Ecology
Exploring the Status of Population Genetics: The Role of Ecology

... required for (indeed, would be impossible to apply to) all evolutionary questions–and one can accept this while still believing that population genetics is essential to evolutionary biology as a whole. In support of the latter point, as many other authors have suggested, consideration of the import ...
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Maximum sustainable yield

In population ecology and economics, maximum sustainable yield or MSY is theoretically, the largest yield (or catch) that can be taken from a species' stock over an indefinite period. Fundamental to the notion of sustainable harvest, the concept of MSY aims to maintain the population size at the point of maximum growth rate by harvesting the individuals that would normally be added to the population, allowing the population to continue to be productive indefinitely. Under the assumption of logistic growth, resource limitation does not constrain individuals’ reproductive rates when populations are small, but because there are few individuals, the overall yield is small. At intermediate population densities, also represented by half the carrying capacity, individuals are able to breed to their maximum rate. At this point, called the maximum sustainable yield, there is a surplus of individuals that can be harvested because growth of the population is at its maximum point due to the large number of reproducing individuals. Above this point, density dependent factors increasingly limit breeding until the population reaches carrying capacity. At this point, there are no surplus individuals to be harvested and yield drops to zero. The maximum sustainable yield is usually higher than the optimum sustainable yield and maximum economic yield.MSY is extensively used for fisheries management. Unlike the logistic (Schaefer) model, MSY has been refined in most modern fisheries models and occurs at around 30% of the unexploited population size. This fraction differs among populations depending on the life history of the species and the age-specific selectivity of the fishing method.However, the approach has been widely criticized as ignoring several key factors involved in fisheries management and has led to the devastating collapse of many fisheries. As a simple calculation, it ignores the size and age of the animal being taken, its reproductive status, and it focuses solely on the species in question, ignoring the damage to the ecosystem caused by the designated level of exploitation and the issue of bycatch. Among conservation biologists it is widely regarded as dangerous and misused.
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