Recruitment as a driver of production dynamics in stream-resident brown trout (Salmo trutta)
TL;DR: The functional relationships between recruitment and the population attributes elucidated in this study appear to provide a useful tool for management applications, including forecasting population status.
Abstract: Summary
1. The objective was to assess the role of recruitment as a determinant of the production dynamics of stream-resident brown trout (Salmo trutta) across replicate habitats of contrasting quality and population attributes. A total of 128-year-classes (YC) at 12 stream sites were examined along four tributaries of the Rio Esva drainage (northwestern Spain).
2. A meta-comparison revealed that growth, density, mortality and production were essentially site-specific. However, when all data were pooled, recruitment (as a delayed density-dependent process) affected both growth and mortality in a way such that individuals in YC with high recruitment grew less and had higher mortality.
3. The value of total YC production recorded covered the global range of variation in the production of stream salmonids reported in the literature. Linear regressions of log-transformed data revealed that 89.0%, 58.9% and 70.7% of the variation in YC density, biomass and production, respectively, were explained by variations in recruitment.
4. The inclusion of growth and mortality, together with recruitment, into a multiple regression increased the variance explained of the total YC production by 13.3%, from 70.7% to 84.0%.
5. The functional relationships between recruitment and the population attributes elucidated in this study appear to provide a useful tool for management applications, including forecasting population status.
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Book•
22 Aug 2011
TL;DR: The nature of Droughts and their assessment can be found in this article, where the authors discuss water bodies, catchments, and the abiotic effects of drought, as well as the human-induced exacerbation of Drought Effects on Aquatic Ecosystems.
Abstract: Acknowledgements. 1. Introduction: The Nature of Droughts. 2. Types of Drought and their Assessment. 3. The Perturbation of Hydrological Drought. 4. Droughts of the Past: Dendrochronology and Lake Sediments. 5. Water bodies, catchments and the abiotic effects of drought. 6. Drought and Temporary Waters. 7. Drought, Floodplain Rivers and Wetland Complexes . 8. Drought and Perennial Aquatic Systems: Plants and Invertebrates. 9. Drought and Fish of Standing and Flowing Waters. 10. Estuaries and Drought. 11. Human-induced exacerbation of Drought Effects on Aquatic Ecosystems. 12. Conclusions. References. Index.
205 citations
TL;DR: Results suggest that restoration measures attempting to increase population abundance through stocking, increased breeding dispersion or cohort survival may reduce the performance of both the enhanced and competing cohorts, which may lead populations occurring at low carrying capacities to extinction.
56 citations
TL;DR: This study highlights the need to understand more fully the mechanism behind the rapid decline in chinook salmon numbers in the wild that has occurred over the past 50 years.
Abstract: YOICHIRO KANNO*, KASEY C. PREGLER*, NATHANIEL P. HITT , BENJAMIN H. LETCHER , DANIEL J . HOCKING AND JOHN E. B. WOFFORD *Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC, U.S.A. Leetown Science Center, United States Geological Survey, Kearneysville, WV, U.S.A. Silvio O. Conte Anadromous Fish Research Branch, Leetown Science Center, United States Geological Survey, Turners Falls, MA, U.S.A. Shenandoah National Park, Luray, VA, U.S.A.
47 citations
TL;DR: In this paper, the authors examined the explanatory power of density dependence, flow and water temperature on the per capita rate of change and growth (annual mean total length) for the whole population, adults, 1+ and young-of-the-year (YOY) brook trout (Salvelinus fontinalis) in Hunt Creek, Michigan, USA, between 1951 and 2001.
Abstract: Summary
1. Fisheries models generally are based on the concept that strong density dependence exists in fish populations. Nonetheless, there are few examples of long-term density dependence in fish populations.
2. Using an information theoretical approach (AIC) with regression analyses, we examined the explanatory power of density dependence, flow and water temperature on the per capita rate of change and growth (annual mean total length) for the whole population, adults, 1+ and young-of-the-year (YOY) brook trout (Salvelinus fontinalis) in Hunt Creek, Michigan, USA, between 1951 and 2001. This time series represents one of the longest quantitative population data sets for fishes.
3. Our analysis included four data sets: (i) Pooled (1951–2001), (ii) Fished (1951–65), (iii) Unfished (1966–2001) and (iv) Temperature (1982–2001).
4. Principle component analyses of winter flow data identified a gradient between years with high mean daily winter flows, high daily maximum and minimum flows and frequent high flow events, and years with an opposite set of flow characteristics. Flows were lower during the Fished Period than during the Unfished Period. Winter temperature analyses elucidated a gradient between warm mean, warm minimum and maximum daily stream temperatures and a high number of minimum daily temperatures >6.1 °C, and years with the opposite characteristics. Summer temperature analyses contrasted years with warm summer stream temperatures vs years with cool summer stream temperatures.
5. Both YOY and adult densities varied several-fold during the study. Regression analysis did not detect a significant linear or nonlinear stock–recruitment relationship. AIC analysis indicated that density dependence was present in 15 of 16 cases (four population segments × four data sets) for both per capita rate of increase (wi values 0.46–1.00) and growth data (wi values 0.28–0.99). The almost ubiquitous presence of density dependence in both population and growth data is concordant with results from other trout populations and other studies in Michigan.
46 citations
TL;DR: There was no evidence that density‐dependent effects were restricted to a particular habitat type or geographic region, and most salmonid species showed evidence of density‐dependence in growth; however, few studies examined density‐ dependent effects on fecundity or recruitment, and further study is needed on these phenomena.
Abstract: We reviewed 199 published data sets (21 species) to assess the relative frequency of various density‐dependent processes in salmonids. We examined studies for the presence or absence of density‐dependence: in growth, mortality, fecundity and recruitment. Based on data from all studies pooled 71% showed density‐dependence in growth, 23% found density‐dependence in mortality, 2% detected density‐dependence in fecundity and 4% displayed density‐dependence in recruitment. Most studies at the population level (e.g. changes in abundance or means of growth, mortality or fecundity) demonstrated density‐dependence; however, these studies were not common, likely because they require long time series of data (at least 3–4 times mean generation time for the species). Our review indicated there was no evidence that the probability of finding density‐dependent effects differed among the 21 species examined, but the number of studies per species varied substantially (5 [minimum for analysis] – 20+); hence, this finding should be viewed as tentative. Most salmonid species showed evidence of density‐dependence in growth; however, few studies examined density‐dependent effects on fecundity or recruitment, and further study is needed on these phenomena. There was no evidence that density‐dependent effects were restricted to a particular habitat type or geographic region.
42 citations
References
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TL;DR: Plotting net reproduction (reproductive potential of the adults obtained) against the density of stock which produced them, for a number of fish and invertebrate populations, gives a domed curve whose apex lies above the line representing replacement reproduction.
Abstract: Plotting net reproduction (reproductive potential of the adults obtained) against the density of stock which produced them, for a number of fish and invertebrate populations, gives a domed curve wh...
3,037 citations
"Recruitment as a driver of producti..." refers background in this paper
...The effect of the parental component on recruitment (Ricker, 1954) and the shape of this...
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...regulation concerns the role of the reproductive component of the population for the subsequent abundance of offspring which, in the fishery literature, is known as recruitment (Ricker, 1954), and herein is assumed to be the number of juveniles entering the population as a result of an annual...
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TL;DR: Methods for assessment of fish production in fresh waters, Methods for assessing fish production of fresh waters as discussed by the authors, Methods for assessing fish production from fresh waters in the Persian Gulf, Iran.
Abstract: Methods for assessment of fish production in fresh waters , Methods for assessment of fish production in fresh waters , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
2,191 citations
Book•
01 Jul 2005
TL;DR: The nature of predation, the influence of population interactions on community structure, and Ecological applications at the level of communities and ecosystems are examined.
Abstract: Preface.Introduction.Part 1. ORGANISMS .1. Organisms in their environments: the evolutionary backdrop.2. Conditions.3. Resources.4. Life, death and life histories.5. Intraspecific competition.6. Dispersal, dormancy and metapopulations.7. Ecological applications at the level of organisms and single-species populations Part 2. SPECIES INTERACTIONS.8. Interspecific competition.9. The nature of predation.10. The population dynamics of predation.11. Decomposers and detritivores.12. Parasitism and disease.13. Symbiosis and mutualism.14. Abundance.15. Ecological applications at the level of population interactions Part 3. COMMUNITIES AND ECOSYSTEMS .16. The nature of the community.17. The flux of energy through ecosystems.18. The flux of matter through ecosystems.19. The influence of population interactions on community structure.20. Food webs.21. Patterns in species richness.22. Ecological applications at the level of communities and ecosystems.References.Organism Index.Subject Index
1,906 citations
TL;DR: It is argued that demographic theory suggests that, except under restrictive and unlikely conditions, recruitment must influence local population density to some extent, and the question as to whether the size of a particular population is limited by recruitment is misguided.
Abstract: The majority of marine populations are demographically open; their replenishment is largely or exclusively dependent on a supply of juveniles from the plankton. In spite of much recent research, no consensus has yet been reached regarding the importance of recruitment relative to other demographic processes in determining local population densities. We argue 1. that demographic theory suggests that, except under restrictive and unlikely conditions, recruitment must influence local population density to some extent. Therefore, 2. the question as to whether the size of a particular population is limited by recruitment is misguided. Finally, 3. the effect of recruitment on population size can be difficult to detect but is nonetheless real. A major weakness of most existing studies is a lack of attention to the survival of recruits over appropriate scales of time and space. Acknowledgment of the multifactorial determination of population density should guide the design of future experimental studies of the demography of open populations.
1,290 citations
"Recruitment as a driver of producti..." refers background in this paper
...The notion that recruitment is a major determinant of adult abundance has been documented in marine (Caley et al., 1996; Bradford & Cabana, 1997) and freshwater fishes (Freeman et al....
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Book•
01 Jan 1994
TL;DR: The brown trout is a successful polytypic species and natural selection and genetic differences between brown trout populations are examined, as well as mechanisms responsible for population regulation in young brown trout.
Abstract: 1.: Introduction: the brown trout and quantitative ecology. 2.: The brown trout, a successful polytypic species. 3.: Case-study: population dynamics of migratory brown trout in Black Brows Beck, 1966-1990. 4.: Growth and energetics of brown trout. 5.: Case-study: growth and production of migratory brown trout in Black Brows Beck, 1966-1990. 6.: Ecological differences between brown trout populations. 7.: Natural selection and genetic differences between brown trout. 8.: Mechanisms responsible for population regulation in young brown trout. 9.: General conclusions. References. Author index. Subject index
978 citations
"Recruitment as a driver of producti..." refers background in this paper
...Nevertheless, as in all fish populations (Chambers, 1997), the salmonid life history is typified by high egg survival during the intra-gravel incubation followed by high mortality soon after emergence (Elliott, 1994), such that recruitment is much lower than egg deposition....
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...However, given the variety of population dynamics and life history modes exhibited by stream salmonids (Elliott, 1994; Crisp, 2000), and the variety of streams inhabited by brown trout (Pringle et al....
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