A multidimensional density dependent matrix population model for assessing risk of stressors to fish populations

2020 ◽  
Vol 201 ◽  
pp. 110786
Author(s):  
David H. Miller ◽  
Bryan W. Clark ◽  
Diane E. Nacci
Keyword(s):  
Population Model ◽  
Fish Populations ◽  
Matrix Population Model ◽  
Density Dependent

Stability and return times of Leslie matrices with density-dependent survival: applications to fish populations

1980 ◽  
Vol 8 ◽  
pp. 149-163 ◽  
Author(s):  
D.L. Deangelis ◽  
L.J. Svoboda ◽  
S.W. Christensen ◽  
D.S. Vaughan
Keyword(s):  
Fish Populations ◽  
Density Dependent ◽  
Return Times ◽  
Leslie Matrices

scholarly journals An integrated population model for estimating the relative effects of natural and anthropogenic factors on a threatened population of Pacific trout

2019 ◽  
Author(s):  
Mark D. Scheuerell ◽  
Casey P. Ruff ◽  
Joseph H. Anderson ◽  
Eric M. Beamer
Keyword(s):  
At Risk ◽  
Population Model ◽  
Habitat Restoration ◽  
Negative Relationship ◽  
Anthropogenic Factors ◽  
List Type ◽  
Population Demographics ◽  
Density Dependent ◽  
Integrated Population Model ◽  
The North

SummaryAssessing the degree to which at-risk species are regulated by density dependent versus density independent factors is often complicated by incomplete or biased information. If not addressed in an appropriate manner, errors in the data can affect estimates of population demographics, which may obfuscate the anticipated response of the population to a specific action.We developed a Bayesian integrated population model that accounts explicitly for interannual variability in the number of reproducing adults and their age structure, harvest, and environmental conditions. We apply the model to 41 years of data for a population of threatened steelhead troutOncorhynchus mykissusing freshwater flows, ocean indices, and releases of hatchery-born conspecifics as covariates.We found compelling evidence that the population is under strong density dependence, despite being well below its historical population size. In the freshwater portion of the lifecycle, we found a negative relationship between productivity (offspring per parent) and peak winter flows, and a positive relationship with summer flows. We also found a negative relationship between productivity and releases of hatchery conspecifics. In the marine portion of the lifecycle, we found a positive correlation between productivity and the North Pacific Gyre Oscillation. Furthermore, harvest rates on wild fish have been sufficiently low to ensure very little risk of overfishing.Synthesis and applications.The evidence for density dependent population regulation, combined with the substantial loss of juvenile rearing habitat in this river basin, suggests that habitat restoration could benefit this population of at-risk steelhead. Our results also imply that hatchery programs for steelhead need to be considered carefully with respect to habitat availability and recovery goals for wild steelhead. If releases of hatchery steelhead have indeed limited the production potential of wild steelhead, there are likely significant tradeoffs between providing harvest opportunities via hatchery steelhead production, and achieving wild steelhead recovery goals.

Rapid growth and large body size in annual fish populations are compromised by density‐dependent regulation

2019 ◽  
Vol 95 (2) ◽  
pp. 673-678 ◽  
Author(s):  
Milan Vrtílek ◽  
Jakub Žák ◽  
Matej Polačik ◽  
Radim Blažek ◽  
Martin Reichard
Keyword(s):  
Body Size ◽  
Rapid Growth ◽  
Large Body ◽  
Fish Populations ◽  
Large Body Size ◽  
Annual Fish ◽  
Density Dependent ◽  
Density Dependent Regulation
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