Allen F. Evans
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Publications 31
#1Quinn PaytonH-Index: 2
#2Nathan J. Hostetter (UW: University of Washington)H-Index: 2
Last. Allen F. EvansH-Index: 14
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Identifying where, when, and how many animals live and die over time is principal to understanding factors that influence population dynamics. Capture–recapture–recovery (CRR) models are widely used to estimate animal survival and, in many cases, quantify specific causes of mortality (e.g., harvest, predation, starvation). However, the restrictive CRR framework can inhibit the consideration and inclusion of some types of recovery data. We developed an extension to the CRR framework to allow for ...
1 CitationsSource
#1Nathan J. Hostetter (NCSU: North Carolina State University)H-Index: 2
#2Beth Gardner (UW: University of Washington)H-Index: 26
Last. Daniel D. Roby (USGS: United States Geological Survey)H-Index: 30
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We developed a state-space mark–recapture–recovery model that incorporates multiple recovery types and state uncertainty to estimate survival of an anadromous fish species. We apply the model to a dataset of outmigrating juvenile steelhead trout (Oncorhynchus mykiss (Walbaum, 1792)) tagged with passive integrated transponders, recaptured during outmigration, and recovered on bird colonies in the Columbia River basin (2008–2014). Recoveries on bird colonies are often ignored in survival studies b...
2 CitationsSource
#1Allen F. EvansH-Index: 14
#2Bradley M. CramerH-Index: 3
Last. Peter J. LoschlH-Index: 6
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#1Allen F. EvansH-Index: 14
#2David A. HewittH-Index: 6
Last. Daniel D. Roby (USGS: United States Geological Survey)H-Index: 30
view all 6 authors...
AbstractWe evaluated predation on Lost River Suckers Deltistes luxatus and Shortnose Suckers Chasmistes brevirostris by American white pelicans Pelecanus erythrorhynchos and double-crested cormorants Phalacrocorax auritus nesting at mixed-species colonies in the Upper Klamath Basin of Oregon and California during 2009–2014. Predation was evaluated by recovering (detecting) PIT tags from tagged fish on bird colonies and calculating minimum predation rates, as the percentage of available suckers c...
3 CitationsSource
AbstractWe evaluated the impact of predation on juvenile steelhead Oncorhynchus mykiss and yearling and subyearling Chinook Salmon O. tshawytscha by piscivorous waterbirds from 11 different breeding colonies in the Columbia River basin during 2012 and 2014. Fish were tagged with both acoustic tags and PIT tags and were tracked via a network of hydrophone arrays to estimate total smolt mortality (1 – survival) at various spatial and temporal scales during out-migration. Recoveries of PIT tags on ...
9 CitationsSource
AbstractTrait-selective mortality is of considerable management and conservation interest, especially when trends are similar across multiple species of conservation concern. In the Columbia River basin, thousands of juvenile Pacific salmonids Oncorhynchus spp. are collected each year and are tagged at juvenile bypass system (JBS) facilities located at hydroelectric dams, thus allowing the tracking of population-level performance metrics (e.g., juvenile survival and juvenile-to-adult survival). ...
2 CitationsSource
AbstractAccurate assessment of specific mortality factors is vital to prioritize recovery actions for threatened and endangered species. For decades, tag recovery methods have been used to estimate fish mortality due to avian predation. Predation probabilities derived from fish tag recoveries on piscivorous waterbird colonies typically reflect minimum estimates of predation due to an unknown and unaccounted-for fraction of tags that are consumed but not deposited on-colony (i.e., deposition prob...
14 CitationsSource
#1Allen F. EvansH-Index: 14
#2Quinn PaytonH-Index: 2
Last. Daniel D. RobyH-Index: 30
view all 6 authors...
1 Citations
#1Jessica Y. Adkins (OSU: Oregon State University)H-Index: 5
#2Donald E. Lyons (OSU: Oregon State University)H-Index: 14
Last. Nathan J. HostetterH-Index: 5
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We investigated colony size, productivity, and limiting factors for five piscivorous waterbird species nesting at 18 locations on the Columbia Plateau (Washington) during 2004–2010 with emphasis on species with a history of salmonid (Oncorhynchus spp.) depredation. Numbers of nesting Caspian terns (Hydroprogne caspia) and double-crested cormorants (Phalacrocorax auritus) were stable at about 700–1,000 breeding pairs at five colonies and about 1,200–1,500 breeding pairs at four colonies, respecti...
5 CitationsSource