AUTHORS: Steven J. Herrington, The Nature Conservancy, MN-ND-SD; Tyler Winter, Native Fish For Tomorrow; Solomon R. David, The University of Minnesota Matthew L. Miller, The Nature Conservancy, Science Communications
ABSTRACT: North America has the highest diversity of freshwater fishes of any temperate region worldwide. These species face numerous threats to their long-term conservation. Fisheries management is amongst the tools that governments, Tribes, and other interested parties can use to ensure this biodiversity sustainably persists and thrives into the future. “Rough fish” is a pejorative term often used by resource managers and anglers to group a large number of native fishes – including gars and numerous sucker species – that are perceived to have little fisheries or cultural value, and thus are often poorly managed and exploited. In 2024, the State of Minnesota passed the first law in the U.S. affording fisheries management protections for 26 native fishes now recognized by the state as “native rough fish”. This action sets a precedent for recognizing the inherent, cultural, and fisheries importance of these species that can be replicated or adapted by other states nationwide. This presentation will provide an historical perspective of “rough fish” regulations, recommendations for their future conservation management, and applicability to states in the Midwest.
AUTHORS: Samantha A. Embersits, Wisconsin Cooperative Fishery Research Unit; Daniel A. Isermann, U.S. Geological Survey, Wisconsin Cooperative Fishery Research Unit; Daniel J. Dembkowski, Wisconsin Cooperative Fishery Research Unit; Margaret H. Stadig, Wisconsin Department of Natural Resources
ABSTRACT: The Lake Winnebago System (LWS) population in east-central Wisconsin represents one of the largest self-sustaining populations of lake sturgeon Acipenscer fulvescens in North America that supports an annual spearing fishery each February. Lake sturgeon spawn at more than 70 locations within tributaries to the LWS, but the extent and timing of spawning that occurs at many sites remains unknown. Understanding lake sturgeon use of spawning locations is important in allocating sampling effort needed to mark fish and obtain population estimates used in setting safe harvest levels for the fishery. Furthermore, some spawning sites represent habitat improvement efforts implemented by the Wisconsin Department of Natural Resources and little to no evaluation has been performed at these sites to determine relative use and potential for successful hatching. Our objectives were to describe lake sturgeon use, measure egg deposition rates and survival, and verify whether hatching is occurring at selected spawning locations in the Wolf River drainage, including sites where habitat improvements have occurred. Spawning sites were or will be visited repeatedly during the 2024 and 2025 spawning seasons and lake sturgeon are visually counted along defined transects. Eggs are collected with a manual transfer pump and D-frame drift nets are used to collect larvae. We will present results from our first sampling season. The information from our research may help the Wisconsin Department of Natural Resources strategically allocate spring sampling effort so that more sites can be sampled and could provide guidance regarding future habitat improvement projects.
AUTHORS: Juliana Kaloczi, Iowa State University; Michael J Moore, U.S Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit and Iowa State University; Martin Hamel, University of Georgia; Gene Jones, Iowa Department of Natural Resources; Ryan Hupfeld, Iowa Department of Natural Resources, Rebecca Krogman, Iowa Department of Natural Resources.
ABSTRACT: Globally, sturgeon populations have declined due to overharvest for caviar and habitat fragmentation due to dam construction that impairs water quality and disrupts spawning migrations. North American species have had harvest restrictions enacted to recover populations. While similar life history characteristics make Shovelnose Sturgeon vulnerable to many of these same stressors, populations in the Mississippi River basin still support limited commercial and recreational fisheries for roe and meat - conferring the species’ economic, recreational, and cultural importance. Enacting harvest regulations, such as minimum length limits, ensures sustainable harvest and requires knowledge of dynamic rates such as age-specific growth rates. However, the Shovelnose Sturgeon’s long life span and slow growth make estimating these parameters notoriously difficult with traditional methods that rely on annuli counts on bony structures. As a result, there is a lack of reliable growth rates for this species across its range. Therefore, we used an 18-year mark-recapture dataset for Shovelnose Sturgeon collected by the Iowa Department of Natural Resources in the Cedar River at Palisades-Kepler State Park to evaluate incremental growth models for Shovelnose Sturgeon. The Fabens modification of the Von Bertalanffy growth function was used within a Bayesian framework to determine how growth rates vary within the population. Additionally, bomb-radiocarbon age estimates were used to inform a second model within the Bayesian framework to assess how the incorporation of previous knowledge may improve the model. Age estimates and growth rates can be used in population simulations to evaluate sensitivity to harvest under harvest regulations and can inform management across the species’ range.
AUTHORS: Andrew Briggs, Michigan Department of Natural Resources; Justin Chiotti, U.S. Fish and Wildlife Service; James Boase, U.S. Fish and Wildlife Service; Jan-Michael Hessenauer, Michigan Department of Natural Resources; Jeannette Kanefsky, Michigan State University; Brad Utrup, Michigan Department of Natural Resources; Todd Wills, Michigan Department of Natural Resources
ABSTRACT: The Michigan Department of Natural Resources (MDNR) and U.S. Fish and Wildlife Service (USFWS) have been conducting Lake Sturgeon surveys in the St. Clair – Detroit River System (SCDRS) since 1996. Over this period determining sex of Lake Sturgeon has been difficult as the primary method to determine sex has been expulsion of gametes, which rarely occurs (particularly for females). Recent advances in genetic methods have shown that sex of Lake Sturgeon can be determined from a tissue sample or fin clip through molecular sexing. MDNR and USFWS have collected pectoral fin rays from Lake Sturgeon for aging purposes since their surveys began and have stored them over the years, allowing for a portion of these fin samples to be clipped and used for molecular sexing. MDNR and USFWS combined to provide over 2,700 tissue samples to Michigan State University for molecular sexing with 53% of the Lake Sturgeon being classified as female. This presentation will examine if sex ratios differed by location within the SCDRS, how sex ratios change by length, and sex-specific growth rates of Lake Sturgeon.
AUTHORS: Justin Sturtz, South Dakota State University; Benjamin J. Schall, South Dakota Department of Game, Fish and Parks; Matthew J. Ward, South Dakota Department of Game, Fish and Parks; Cody E. Treft, South Dakota Department of Game, Fish and Parks; Christopher Cheek, South Dakota State University
ABSTRACT: Determining the natal origins of fish can provide critical information for fisheries management and conservation efforts. Recirculating Aquaculture Systems (RAS) are advanced, fish-rearing setups that filter and recycle water within the system, significantly reducing the need for fresh water and allowing for high-density rearing of fish under efficient growth conditions. In contrast, traditional fish stocking often involves rearing fish in raceways or outdoor ponds. Differences in forage between RAS (pellet-fed) and pond (natural forage) reared fish may result in unique isotopic signatures in the fish tissue. Historically archived isotope signatures in fish eye lenses may be useful in differentiating rearing sources, providing an additional tool for delineating stock contribution. This study investigates the feasibility of using isotopic composition of fish eye lenses to discern the known rearing environment (RAS vs. pond vs. wild) of fall, advanced fingerling age-0 Walleye (Sander vitreus). We collected 10 RAS-reared, pellet-fed walleye from Cleghorn fish hatchery in Rapid City SD (mean = 159mm), 10 pond-reared natural source-fed walleye from Blue Dog hatchery in Waubay SD (mean = 179mm), and 10 wild- caught walleye from Clear Lake in Sioux Falls SD (mean = 170mm). Eye lens layers were delaminated to remove ~300 µm for each layer, resulting in 3 to 4 layers per fish including the core. Eye lens layers were sent for carbon (δ13C) and nitrogen (δ15N) isotope analysis, and whole eye lenses from the second eye were sent for δ13C, δ15N, and sulfur (δ34S) analysis. Preliminary δ13C and δ15N results illustrated unique signatures among stocking sources, high signature precision for the pellet-fed RAS fish, and shifting signatures with known changes in diet for pond-reared fish. The results of this study could be used by managers who are focusing on identifying the stock contribution of RAS and pond-reared fishes.
ABSTRACT: The beginning of formal fish culture in North America dates back to the 1800s when some of the first references to hatcheries being used for population mitigation purposes surfaced. While the early efforts were focused on the actual science of fish culture, the need to support culture efforts with facilities specifically designed to aid production soon followed. The design of coolwater, warmwater and coldwater fish production facilities ranges from simple repairs at existing facilities to full scale renovations or brand new state of the art hatcheries that can meet the needs of conservation based fish culture. This talk will outline the history of facilities in North America and highlight design features utilized for sportfish and conservation focused facilities.
ABSTRACT: The origin of fish propagation for population recovery dates back to the mid-1800s. Throughout the centuries to follow, fish hatcheries have been designed to focus on mass production. While previous criticisms of such mass production were founded on the basis of environmental harm – including nutrient pollution from fish waste, extirpation of native species by hatchery fish, disease, and the introduction of invasive species – fish hatchery management has entered a new era. Fish hatcheries are now shifting the production focus to enhance conservation and recovery programs of native fishes, in addition to sport fish production. HDR has constructed a tool to help guide management decisions for designing facilities surrounding such programs. Fish hatchery biological programming (“bioprogramming”) is a tool used to analyze biological questions and anticipate the fish rearing environments necessary to answer these questions. The process references fish culture specifications obtained from recognized fish culture manuals, established fish rearing facilities, and fish production managers. The modeling process anticipates fish growth, desired rearing space, and required flow and oxygen demands to produce healthy fish, making it a valuable tool for managing challenges and conflicts in fish hatchery design. It has been used to model and support recovery strategies for several fish species across North America, including Gila trout in Arizona, Pacific salmon species in Washington, coolwater fish in the Midwest, and salmonid species in Canada.
AUTHORS: Steven Gratz, The Ohio State University; Jacob Bentley, The Ohio State University; Stuart Ludsin, The Ohio State University
ABSTRACT: Fatty acids are vital for human health and affect overall well-being while reducing disease risk. Fish tissue contains a plethora of fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two essential omega-3 fatty acids, which are primarily found in fish and help the human body to function properly. Little research has been conducted studying the fatty acid composition of freshwater fishes with a majority of research focusing on saltwater fishes. However, it is important to understand the fatty acid composition among freshwater fishes that support locally sourced food. We sought to understand species, size, and seasonal variation of saturated and unsaturated fatty acids in Blue Catfish (Ictalurus furcatus) and Channel Catfish (I. punctatus) within two central Ohio Reservoirs to help locavores make informed decisions on which type of fish to consume. Belly fillets with skin attached were collected from Blue Catfish (n=37) and Channel Catfish (n=39) in the summer and fall of 2022 from Hoover Reservoir and Channel Catfish were also collected from Alum Creek Reservoir in the summer of 2022 using short-term gill net sets. We hypothesized that beneficial fatty acid concentrations would vary with environmental seasonal changes (e.g., water temperature) and fish size and species due to differences in feeding ecology. We also expected to observe increasing concentrations of EPA and DHA with an increase in fish size. While understanding the fatty acid composition of different fishes can help locavores make informed decisions, it is dually important to conduct a risk-benefit assessment to ensure that fish have adequate levels of fatty acids while also following fish consumption guidelines to maintain a safe level of contaminant exposure.
AUTHORS: Shasta Kamara, Program of Ecology, Evolution, and Conservation Biology, University of Illinois Urbana-Champaign; Jackson Glomb, Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign; Cory Suski, Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign
ABSTRACT: American Paddlefish (Polyodon spathula) have important commercial and recreational fisheries throughout their range, which covers a wide latitudinal gradient. Seasons for Paddlefish angling and harvest are broad and often set by dates, and, as a result Paddlefish can experience capture and release across a range of temperatures. Currently, the impact of thermal variation on Paddlefish response to capture stressors has not been defined, precluding us from making informed management decisions regarding the timing and duration of angling and harvest seasons. Therefore, the objective of this study was to quantify the response of Paddlefish to simulated capture and release across a range of temperatures using two experimental approaches. In the first study, juvenile Paddlefish were acclimated to 13, 17.5, and 22° C. Fish from each of these temperatures were subjected to a simulated angling experience and recovered for 30 minutes, 4 hours, or 8 hours; a second group of fish were given a critical thermal maximum test (CTmax) to quantify heat tolerance. The second study sought to quantify post-release behavior of adult Paddlefish after simulated commercial capture at different temperatures using tri-axial accelerometers. Results from the first study showed that Paddlefish acclimated to 13°C recovered from exercise within 4 hours, while fish acclimated to 22°C did not recover, even after 8 hours. The 17.5°C and 22.0°C treatments had higher CTmax than the 13.0°C treatment suggesting an upper limit to thermal tolerance. Results thus far indicate that Paddlefish experiencing warmer temperatures have reduced performance relative to cooler fish, suggesting that temperatures over 20 degrees may be stressful for released Paddlefish after exercise. Together, these projects can help inform how Paddlefish respond to capture stressors across a range of temperatures and inform future management options to minimize impacts on individuals.
AUTHORS: Israt Jahan, Samodha Fernando, Chris Chizinski, Mark Pegg
ABSTRACT: The gut microbiome plays a vital role in the health and survival of aquatic species, including the endangered Pallid Sturgeon (Scaphirhynchus albus), which is experiencing reproductive challenges due to habitat alterations. While hatchery augmentation remains a key strategy to bolster Pallid Sturgeon populations, the reduced survival rates of hatchery-raised individuals present a significant obstacle to delisting efforts. This study investigates the gut microbiomes of wild-caught Pallid Sturgeon from Platte River and hatchery-raised Pallid Sturgeon from Gavin's Point National Fish Hatchery to identify differences and their potential management implications. Fecal samples were collected from both groups, and the 16S rRNA gene was amplified to sequence and characterize the microbial communities present. Findings indicate that wild-caught sturgeon exhibit a more diverse and adapted gut microbiome than their hatchery-raised counterparts. These differences may challenge hatchery-raised individuals in adapting to natural environments post-release, potentially affecting their survival and reproductive success. Furthermore, alterations in gut microbiota composition may influence nutrient absorption, immune function, and overall health. Integrating gut microbiome dynamics into management strategies is essential for conserving endangered species, underscoring the necessity for adaptive management approaches incorporating microbial ecology principles to ensure the long-term survival of Pallid Sturgeon populations.
