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dc.contributor.authorSchulze, Joshua C.
dc.date.accessioned2021-02-01T19:31:05Z
dc.date.available2021-02-01T19:31:05Z
dc.date.issued2017-05
dc.identifier.urihttp://digital.library.wisc.edu/1793/81106
dc.description.abstractLake sturgeon Acipenser fulvescens populations have declined dramatically over the last two centuries due to overharvest, water pollution, and habitat fragmentation. Lake sturgeon are now listed as endangered, threatened, or a species of concern in many waters where they occur, including many portions of the Great Lakes. While management practices and environmental regulations have curtailed overharvest and improved water quality, most Great Lakes tributaries remain fragmented by hydroelectric dams. Dams have been identified as the largest remaining obstacle to lake sturgeon recovery in the Great Lakes as they prevent lake sturgeon from accessing historic spawning and rearing habitat. Dam removal is not generally considered an option because most hydroelectric dams are actively producing energy. Therefore, an alternative solution is required. Capturing lake sturgeon downstream of hydroelectric dams and releasing them upriver is a potential method of providing lake sturgeon access to upriver habitat. While conceptually sound, this management strategy has not been studied with sufficient rigor to determine if the approach is successful in meeting management or restoration objectives. The Menominee River that borders the states of Wisconsin and Michigan supports the largest naturally-reproducing stock of lake sturgeon in Lake Michigan, but juvenile habitat available downstream of the lowest dam (i.e., Menominee Dam) is considered poor and better habitat is available upstream (Daugherty et al. 2009). Construction of a fish elevator in Menominee Dam provided the means to capture lake sturgeon for passage upstream of the lowest two dams to a section of river where better habitat exists. However, information on the behavior of lake sturgeon after passage was needed to determine if this strategy might be effective for augmenting lake sturgeon recruitment in the Menominee River and if these fish returned to the lower Menominee River. Consequently, my research objectives were to determine if: 1) adult lake sturgeon passed upstream have the opportunity to spawn at least once upstream of Park Mill Dam; 2) opportunity to spawn is related to sex, length of fish, and season of passage; 3) adult lake sturgeon passed upstream return downstream to the lower Menominee River; and 4) downstream passage rate and timing at Park Mill and Menominee dams are related to season of passage, time elapsed since passage occurred, river flow, or water temperature. Adult lake sturgeon (n = 113) were captured from the lower Menominee River using the elevator and electrofishing and were transported and released upstream of the two lowest dams into a 31-km section of river (between Grand Rapids and Park Mill dams). Lake sturgeon were released in Fall 2014, Spring 2015, Fall 2015, and Spring 2016. Sex and maturity stage were initially determined via portable ultrasound. The majority (88%; 100 of 113) of fish selected for passage were expected to spawn that spring (spring passage) or the following spring (fall passage; i.e., F4 or M2 stage fish). All lake sturgeon passed upriver were measured for total length, received a PIT tag, and a fin clip was removed for genetic stock assignment. A subset of 50 male, 46 female, and 4 lake sturgeon of unknown sex (total n = 100) were implanted with 10- year acoustic transmitters. Movements of acoustically transmittered lake sturgeon were monitored with stationary receivers positioned at numerous locations throughout the study area. After release 86% (86 of 100) of lake sturgeon moved upstream to within 1 km of Grand Rapids Dam (i.e., upstream extent of USF). Eighty three percent (73 of 88 fish) of ready-to-spawn fish of known sex that were implanted with acoustic transmitters remained upstream of Park Mill Dam for at least one spawning opportunity. No significant difference existed between the percentage of males (82%; 40 of 49) and females (85%; 33 of 39) with at least one spawning opportunity upstream, and spawning opportunity did not differ between lake sturgeon passed upstream during spring (82%; 40 of 49) or fall (85%; 33 of 39). Similarly, no significant difference existed between percent of small (< 152 cm TL) vs. large (≥ 152 cm TL) female lake sturgeon with at least one spawning opportunity upstream of Park Mill Dam (95% and 75%, respectively) or between percent of small (< 136 cm TL) vs. large (≥ 136 cm TL) male lake sturgeon (87% and 77%, respectively). Lake sturgeon exhibited a 17% probability of passing downstream of Park Mill Dam in spring (March, April, May) and an 8% probability in both summer (June, July, August) and fall (September, October, November) each month after passage. No lake sturgeon passed downstream of either dam in winter (December, January, and February). Probabilities of downstream passage at Menominee Dam were 36, 42, and 33% for spring, summer, and fall. Overall, 37 of the acoustically transmittered fish were still upstream of both dams as of 31 August 2016 (16 male, 19 female, 2 unknown; 27 spring-passed, 10 fall-passed), 6 were between the dams (1 male, 4 female, 1 unknown; 3 spring-passed, 3 fall-passed), and 57 were downstream of both dams (33 male, 23 female, 1 unknown; 27 spring-passed, 30 fall-passed). A downstream bypass structure at Park Mill Dam was used by 10% (6 of 63) of lake sturgeon to pass Park Mill Dam; 57 passed through spill gates. The downstream bypass structure at Menominee Dam was not operational so the 57 lake sturgeon that moved downstream passed Menominee Dam did so through open spill gates. Mean time spent upstream of Park Mill Dam was 5.9 months (range = 0 – 18.7 months), while average time spent between Park Mill and Menominee dams was 2.1 months (range = 0 – 18.8 months). The average time before lake sturgeon returned to the lower Menominee River was 8.8 months (range = 0.1 – 19.3 months). Genetic techniques assigned 110 lake sturgeon to the Menominee River, 1 to the Fox River, 1 lake sturgeon was of undetermined origin, and 1 lake sturgeon was not genotyped. Lake sturgeon passed upstream generally remained upstream of Park Mill Dam in a 31 km stretch of river for at least one spawning opportunity, regardless of sex or the season when passage occurred (spring vs. fall). This is important because if fish did not remain upstream to spawn, passage efforts would not be effective for increasing lake sturgeon recruitment within the Menominee River. Although the assessment of downstream passage is not complete as 37 lake sturgeon were still upstream and the Menominee Dam downstream bypass was not operational during this study, my results suggest that the majority of fish eventually return to the lower Menominee River over time. This finding suggests passage of lake sturgeon on an annual basis would be needed to augment levels of recruitment upriver. Additionally, my initial monitoring suggests that upstream passage may not represent a net loss of mature lake sturgeon from the Lake Michigan population (i.e., fish return to lower Menominee River), which would likely offset efforts to increase recruitment. My initial assessment also suggests that making downstream passage available to lake sturgeon during April and May and to a lesser extent in October will be critical to ensuring lake sturgeon can move back downstream after passage. Future research is needed to determine if fish passed upstream are producing recruits and if these recruits eventually make it downstream to contribute to the Lake Michigan lake sturgeon population. Continued monitoring of lake sturgeon will provide greater insight on downstream movements and lake sturgeon use of downstream passage facilities. Nearly all lake sturgeon captured downstream of Menominee Dam genetically assign to the Menominee River which is important for determining if upstream passage might lead to mixing of genetically distinct stocks from Lake Michigan.en_US
dc.description.sponsorshipGreat Lake Fish and Wildlife Restoration Act, and WE Energies Mitigation and Enhancement Funden_US
dc.language.isoen_USen_US
dc.publisherUniversity of Wisconsin-Stevens Point, College of Natural Resourcesen_US
dc.titleLake Sturgeon Movement After Upstream Passage of Two Hydroelectric Dams on the Menominee River, Wisconsin-Michiganen_US
dc.typeThesisen_US


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