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Andrew T. Mueller

Publications and source records attributed to Andrew T. Mueller.

6 recordsLinked to original sources
USGS2026

Beyond barriers: Fish assemblage recovery following dam removal on the Cuyahoga River, a Lake Erie tributary

Dam removals are increasing globally, yet ecological outcomes vary widely because biological recovery depends on post-removal connectivity and access to source populations. We evaluated how multiple dam removals and remaining fragmentation influenced fish assemblage recovery in the Cuyahoga River (OH, United States), a historically polluted Great Lakes tributary now undergoing extensive remediation and restoration. Using fish assemblage data collected from 1984 to 2024 across reaches downstream, within, and upstream of the Gorge Plant Dam (GPD), an 18-m barrier slated for removal, we quantified spatial and temporal change with ordination, trajectory, and distance-based redundancy analyses. Downstream assemblages showed a clear shift through time and gained 15 newly detected taxa after the 2020 Brecksville Dam removal increased longitudinal connectivity to Lake Erie by 39 river kilometers, more than doubling free-flowing habitat below GPD. In contrast, assemblages upstream of GPD exhibited limited change and patterns consistent with redistribution of resident species rather than colonization-driven turnover. Across the full time series, site position relative to GPD and the rate of dam removal were the strongest predictors of assemblage variation, with habitat gradients (e.g. depth, velocity, turbidity, and canopy cover) further differentiating reaches. Together, these results show that connectivity and barrier position shape assemblage recovery following dam removal. Most newly detected taxa downstream were native, though three were nonnative, indicating trade-offs between recolonization and nonnative spread.

Ohio↗
USGS2026

Restoration in motion: Expanded migration and distribution of silver redhorse Moxostoma anisurum and shorthead redhorse M. macrolepidotum

Habitat fragmentation poses a significant threat to migratory species. Dams are a common form of fragmentation, and recent restoration efforts around the Great Lakes have prioritized dam removal. We used acoustic telemetry to describe migratory movements of two redhorse species in the Sandusky and Cuyahoga rivers, Ohio, USA in relationship to habitat reconnection. Shorthead redhorse ( Moxostoma macrolepidotum ) typically migrated from both rivers into Lake Erie between May and July, moving 40–248 km straight-line distance from the river before returning the following spring. We recorded individual cumulative distances up to 809 km between spawning seasons. Shorthead redhorse demonstrated tributary fidelity, but individuals from both rivers co-occurred along southern Lake Erie. Silver redhorse ( M. anisurum ) largely remained in their tagging tributary watersheds year-round. Cuyahoga River silver redhorse moved upstream from March to April 28.8 km on average and passed upstream of the historical Brecksville Dam (removed in 2020), occasionally reaching the next upstream dam. Telemetry data revealed redhorse use of newly available habitat upstream of dam removals and previously undescribed long-range adfluvial migration by shorthead redhorse.

Ohio↗
USGS2025

Long-term surgery survival, body condition effects, and incision healing of Silver Carp and buffalo species comparing sedation methods across seasons

Objective Internal tagging for telemetry studies requires invasive surgery procedures, necessitating sufficient sedation to support animal welfare. Challenges with existing chemical sedatives have resulted in technological alternatives, including electrosedation, with these newer methods less extensively studied. Our primary objective was to understand long-term survival, body-condition effects, and incision healing after surgical implantation of an imitation telemetry transmitter under three different sedation techniques. Methods We collected Silver Carp Hypophthalmichthys molitrix and buffalo Ictiobus spp. from the Missouri River watershed in 2022 and 2023, during each of the four seasons. One of three sedation techniques was applied: electric fish handling gloves, tricaine methanesulfonate (MS-222), and eugenol. Additionally, we observed a group of fish that were unsedated but subjected to handling similar to that experienced during surgery. Fish were monitored to determine the effects of treatment, individual characteristics, surgery characteristics, and time-varying environmental factors on survival, body condition, and incision healing over 69- to 85-d holding periods. Results Long-term survival was higher for buffalo (86%) than Silver Carp (57%), with the fewest mortalities during the winter trial and most in summer, but sedation treatment did not affect survival. Smaller fish had a greater risk of mortality but better incision healing. Incision healing scores improved in warmer temperatures. Conclusions Difference in seasonal effects on survival and healing indicate a need to consider trade-offs when scheduling tagging for projects. However, a lack of difference in survival among treatments, including the group that was handled but did not undergo surgery, suggests no advantage of one sedative over another, but handling impacts may require more consideration.

Transactions of the American Fishery Society↗
USGS2025

Fish-assemblage evaluation in the lower Sandusky River, Ohio, following dam removal

The Sandusky River, Ohio, USA, has experienced more than a century of alterations, including dam implementation and removal, causing a cascade of habitat changes. The physical changes in the river led to establishment of several invasive species. Ten hoop-net sampling sites, spaced about 500 m apart were established in the river to monitor fish assemblage and their habitat preferences. Four 10-d sampling events were completed from April through October 2021. Ordination analyses were used to assess fish-assemblage structure seasonably, species-habitat relationships, and life-history strategies of 31 species. Generalized linear mixed-effects models were used to assess temporal factors that may drive diversity and community assemblage. Models indicated increased species richness after removal of the dam. Presence and proportion of catch data were compared to Ohio Environmental Protection Agency 2009 pre-dam-removal data to further assess changes in fish assemblage. Several species, especially catostomids, have begun to use the habitat downstream of the former dam, altering fish assemblage throughout the river. We expect shifts in assemblage structure to persist, making continued monitoring essential for understanding how non-native and recreationally important species continue to respond to dam removal.

Ohio↗
USGS2019

Semiautomated process for enumeration of fishes from recreational-grade side-scan sonar imagery

The use of hydroacoustic techniques is increasing as scientists search for less invasive ways to monitor fish populations, and using recreational side‐scan sonar (SSS) imagery for monitoring has become more common in aquatic resource management over the last 15 years due in part to its low cost and user‐friendly interface. The time‐consuming nature of manually counting fish targets has limited the use of the data that is collected by these systems in research or management contexts. To reduce the time and effort that is required to enumerate acoustic targets that are presumed to be fish, we developed a semiautomated process that rapidly quantifies targets from recreational SSS imagery by using an open‐source image processing software. Perceived fish targets were enumerated using a set of macroinstructions that performed similarly to manual enumeration by three experienced assessors. This method reduced variation that arises from individual assessors and eliminated the prohibitive time constraints that are associated with manual processing. Herein, we describe how our semiautomated process could be used in fisheries management contexts after further research and development of sampling methods. Future research will focus on field validation, quantifying relative abundance, testing across a broader range of environmental conditions, and exploring other applications for fisheries management.N

North American Journal of Fisheries Management↗