Master of Science, University of Toledo, 2023, Biology (Ecology)

Lake Sturgeon (Acipenser fulvescens) have suffered large populations declines in the last century due to overexploitation, habitat degradation, and pollution. These anthropogenic stressors have extirpated Lake Sturgeon from the Maumee River (Toledo, OH). A reintroduction effort began in 2018 utilizing two different rearing strategies (streamside and traditional hatchery methods), aiming to reestablish a naturally reproducing population (1500 adults) within the Maumee River. However, Lake Sturgeon are not expected to return to rivers to spawn until they are 12-18 years old, making program assessment difficult in a reasonable time frame. Consequently, in order to determine the success of the reintroduction some Lake Sturgeon were implanted with acoustic telemetry tags. Our specific objectives were to: 1 – estimate post stocking survival, 2 – analyze both movement and habitat use post-release, and 3 – determine if differences occurred between rearing strategies. Monthly survival estimates ranged from 87% to 97% in all 3 release years (2018, 2019, and 2021) with no differences between Lake Sturgeon raised in Maumee River water (Toledo Zoo) or at the Genoa National Fish Hatchery (Wisconsin, USA). We found no differences in post-stocking movement or habitat use. In each release year, we found that juvenile Lake Sturgeon exited the river (detected between 3 and 47 days) and remained in the lake for the duration of the track/deployment/tag life up to one-year post-release. Movement patterns and detection locations indicate that the juveniles are primarily utilizing the southern near shore of the west basin and rocky reef complexes. Furthermore, we found that the addition of nearshore receivers in 2019 greatly enhanced our ability to detect juveniles post-release. The success of this work informs us of the ecology of juvenile Lake Sturgeon within the Maumee River and can be used to guide future management strategies pertaining to the reintroduction of Lake Sturgeon within La (open full item for complete abstract)

Committee: William Hintz (Committee Chair); Justin Chiotti (Committee Member); Jonathan Bossenbroek (Committee Member); Christopher Vandergoot (Committee Member); Christine Mayer (Committee Member); Richard Kraus (Committee Member) Subjects: Biology; Ecology; Environmental Science

Doctor of Philosophy, University of Toledo, 2018, Biology (Ecology)

Biodiversity and ecological function are increasingly threatened by human impacts including fragmented systems, modified water and sediment flow, pollution, habitat degradation and alteration, overexploitation of species, and invasive species introduction. These impacts necessitate the need for conservation and restoration practices to protect natural resources and biodiversity. This dissertation outlines the development and implementation of habitat suitability index (HSI) models as tools to support species reintroduction efforts and monitor populations of imperiled species. Lake sturgeon (Acipenser fulvescens), a state listed species in Ohio, are a candidate for reintroduction in the Maumee River, Ohio, where they were historically abundant, but are now functionally extirpated. The goal of my dissertation was to determine if current habitat quantity and quality in the Maumee River are sufficient to support lake sturgeon reintroduction using habitat suitability index models for two important life stages: spawning adult and age-0 fish. The models I developed, using substrate, water velocity, and water depth, indicated that habitat quality, quantity, and connectivity for both spawning adult and age-0 lake sturgeon would support efforts to reintroduce this species. The results of these HSI models were used in the development of a reintroduction plan to summarize important elements for successful reintroduction efforts. The reintroduction plan provided a comprehensive outline incorporating biological, managerial, and societal perspectives, to identify potential barriers to lake sturgeon reintroduction and highlight direct actions to increase success. HSI models are valuable tools for reinforcing species restoration plans and improve conservation monitoring. After the development of the lake sturgeon HSI models for the Maumee River, I wanted to further investigate if the model structure and habitat data could be utilized for other species in the Maumee River. I tested m (open full item for complete abstract)

Committee: Jonathan Bossenbroek PhD (Committee Chair); Christine Mayer PhD (Committee Member); Daryl Moorhead PhD (Committee Member); Todd Crail PhD (Committee Member); Christopher Vandergoot PhD (Committee Member) Subjects: Conservation; Freshwater Ecology