Spawning Stock Abundance And Larval Production Of Lake Sturgeon Acipenser Fulvescens Rafinesque In Black Lake Michigan

Author : Stefan Tucker
Publisher :
ISBN 13 :
Total Pages : 176 pages
Book Rating : 4.:/5 (119 download)

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Download or read book Lake Sturgeon Spawning Behavior, Larval Production and Juvenile Habitat Use Within the Lower Fox River, Wisconsin written by Stefan Tucker and published by . This book was released on 2020 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.