Demographic and Life History Characteristics of Remnant Lake Sturgeon Populations in the Upper Great Lakes Basin PDF Download
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Author: Patrick William DeHaan
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 206
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Author: Patrick William DeHaan
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 206
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Author: David Carl Caroffino
Publisher:
ISBN:
Category : Lake sturgeon
Languages : en
Pages : 256
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"Populations of lake sturgeon Acipenser fulvescens in the Laurentian Great Lakes have not recovered after dramatic declines in the late 1800s despite the implementation of numerous recovery plans. Although extensive lake sturgeon research has and continues to occur, critical knowledge gaps remain. Recruitment of lake sturgeon is variable, but the extent of that variation, its limiting factors, and mortality rates experienced by early life stages are unclear. The purpose of this study was to increase our understanding of lake sturgeon early life stages by examining characteristics of a remnant population in the Peshtigo River, Wisconsin. Specifically, this research sought to empirically estimate rates of early life stage mortality, describe the vertical distribution of drifting larvae, evaluate the impacts of predation on recruitment, and describe patterns in movement and abundance of age-0 juveniles. Extensive sampling of lake sturgeon eggs, larvae, age-0 juveniles, and potential predators occurred during 2006 and 2007. Although drifting lake juveniles potential during sturgeon larvae were captured in all parts of the water column, more were found near the Surface than the substrate. After drifting to nursery areas, individuals exhibited variable movement patterns. Some fish were never recaptured more than 10 m from the initial capture site, while other individuals moved more than 9 km. Even though absolute abundance of juveniles differed by an order of magnitude between 2006 and 2007, a pattern of steady decline during the summer months was similar during both years. This downstream movement may have resulted in emigration from the Peshtigo River, as there was no evidence of predation on this life stage. Overall mortality from the egg to age-0 juvenile life stage exceeded 99.9% in both study years. Predation on eggs was extensive by both crayfish and fish (white sucker Catostomus commersonii), but was minimal on other life stages. These results suggest that recruitment can vary significantly, and predation is likely only limiting at the egg life stage. These results will allow more effective monitoring and management of lake sturgeon early life stages, thereby promoting population recovery"--Leaves iii-iv.
Author: Amy Beth Welsh
Publisher:
ISBN:
Category :
Languages : en
Pages : 266
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Author: Amy M. Schueller
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 350
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Author:
Publisher:
ISBN:
Category : Aquatic sciences
Languages : en
Pages : 774
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Author: Kristin Janet Bott
Publisher:
ISBN:
Category : Endangered species
Languages : en
Pages : 238
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Author:
Publisher:
ISBN:
Category : Fisheries
Languages : en
Pages : 24
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Author: James Andrew Crossman
Publisher:
ISBN:
Category : Fish stocking
Languages : en
Pages : 388
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Author: Stefan Tucker
Publisher:
ISBN:
Category : Lake sturgeon
Languages : en
Pages : 176
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Lake Sturgeon (Acipenser fulvescens) populations have experienced declines throughout much of the Great Lakes and are currently a target for restoration. The Lower Fox River is a highly modified river system that hosts a small remnant Lake Sturgeon population. Previous work confirms annual spawning and some natural reproduction but inconsistent monitoring yields little understanding to current status and sustainability of this population. Chapter 1 describes the biological attributes of the spawning adult stock during 2017-2019 and the environmental conditions surrounding these annual events. In addition to a demographic description of adults, spawning habitat quantity and quality were evaluated to showcase reproductive potential of Lake Sturgeon below the De Pere Dam in the Lower Fox River, Wisconsin. Our description of adult demographics suggest adequate population structure exists to support reproductive success and spawning occurs during favorable seasonal conditions; therefore this population should be capable of significantly higher levels of larval production. Examinations of spawning substrates, incubation habitats and egg predation identified several factors influencing the reproductive success of this population. Locations of spawning activity are problematic on this system due to temporal desiccation events, algae colonization and egg/larval dislodgment which may severely restrict egg and larval survival. Consistent monitoring of spawning adults and larval production would continue to describe the stability of this population. Improvements to habitat quality and quantity should become priority restoration actions to ensure reproductive success. The ability to improve egg and larval survival would provide the opportunity to assign restoration targets and assess the effectiveness of restoration strategies for this population. Chapter 2 continues to evaluate Lake Sturgeon habitat availability in the Lower Fox River by investigating the riverine use of juveniles. Expanding knowledge pertaining to early life stage habitats and movement patterns are listed as a critical need for management. Documented low levels of production within this river system make it uncertain if wild juveniles are present and to what extent nursery habitats exist. Previous habitat models suggest ample juvenile habitat is present, however a legacy of pollution and recent restoration actives to remove contained sediments and improve river condition, make it uncertain if the river is utilized as a nursery area. Age-0 Lake Sturgeon were implanted with hydro-acoustic transmitters and tracked for 40 days during late summer in 2018 and 2019 to document movement patterns and areas of occupancy in the Lower Fox River. Results demonstrate that juvenile Lake Sturgeon will reside in the river system for extended periods of time and congregate into focal habitat areas. Six core habitat areas were identified in the upper river section suggesting the presence of functional nursery habitat. This is the first documentation of juvenile Lake Sturgeon habitat use following restoration activities in the Lower Fox River and will serve to help guide future habitat improvements and further knowledge of juvenile life stage ecology in this river system. The information gathered in this study provides a greater understanding to the reproductive limitations of this population and early life history needs as well as assign restoration targets to improve Lake Sturgeon sustainability in the Lower Fox River.
Author: Gordon R. Priegel
Publisher:
ISBN:
Category : Lake sturgeon
Languages : en
Pages : 20
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