Population Biology Commons^™

Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction As A Mitigation Strategy, Douglass Keiser

Biology Graduate Theses

Over the past several decades, cold- and cool-water fish populations across the Upper Midwest, including Minnesota and Wisconsin, have shown troubling signs of decline. Among the most affected is the walleye/Ogaa (Sander vitreus), a species deeply embedded in the ecological balance, cultural identity, and economic vitality of the region, and central to the lifeways, treaty-reserved rights, and resource stewardship of Tribal Nations, including Ojibwe communities across the Upper Midwest. Despite ongoing stocking efforts and harvest regulations, many lake systems have experienced persistent declines in natural recruitment, prompting resource agencies to investigate the underlying causes. One such system is …

Fisheries Management Paper No.312: Discussion Paper On Management And Licensing Options For The Charter Industry - Statewide Strategic Review Of Western Australia’S Charter Fishing Sector, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

This consultation paper has been prepared to support the statewide strategic review of Western Australia’s (WA) charter fishing sector, which was initiated as a government commitment.

The paper details issues and proposals relating to the management and licensing framework, development opportunities and representation model for the charter fishing industry. The proposals have been developed in consultation with the Charter Review Working Group. The Department of Primary Industries and Regional Development (DPIRD) now seeks comment from relevant stakeholders on the issues and proposals outlined within this paper.

Comments provided will assist in providing advice and recommendations to the Minister for Fisheries …

Teeth That Tell Time: Elemental Analysis From Shark Teeth, Gisele-Elizabeth Perez

Posters - 2026

Sharks (Chondrichthyes) have hunted in the oceans for over 400 million years, their teeth leaving history behind, constantly becoming a part of the fossilization process (Worm et al. 2013). Their survival throughout 5 major extinctions is due to their ability to adapt easily with slow metabolism, a wide range of diet, and an efficient physiology. Shark teeth are vital to the hunting and consumption of their prey, making it a point for scientists to study them. Their tooth minerals contain fluorapatite in their enameloid, and dentin in the “root” of the tooth, with extinct species containing dentin and hydroxyapatite in …

Emerald Bowfin Amia Ocellicauda Ecology In Three Minnesota Lakes: Abundance, Age Analysis, Diet Composition, And Stable Isotope Food Web, Griffin Blegen

Biology Graduate Theses

The Emerald Bowfin Amia ocellicauda is a predatory fish species native to Minnesota that has often been discriminated against. This research expands ecological knowledge of Bowfin in Minnesota and provides population data to guide future management. Bowfin were sampled in the spring of 2024 and 2025 and a multi-census mark–recapture model was used to estimate abundance in three lakes. Estimated populations were 196 individuals in Little Toad Lake (95% CI: 116, 242) or 4.4 fish/littoral ha (95% CI: 2.7,5.7), 657 in Lake Sarah (95% CI: 436, 1014) or 4.2 fish/littoral ha (95% CI: 3.0, 6.7), and 612 in Gun Lake …

Trophic Structure And Mercury Bioaccumulation In Walleye And Yellow Perch In The Upper And Lower Red Lake Basins, Marissa Pribyl

Biology Graduate Theses

Mercury is a persistent global contaminant that biomagnifies through aquatic food webs, with dietary and environmental factors serving as the primary drivers of accumulation in fishes. Trophic structure and methylmercury dynamics in Walleye (ogaa; Sander vitreus) and Yellow Perch (asaawens; Perca flavescens) were investigated in the Upper and Lower Red Lake basins in Red Lake, Minnesota, during 2024-2025. Diets of Walleye and Yellow Perch were assessed through stomach dissections, and tissue samples from both species were analyzed for total mercury concentrations. Additional analyses included shiners (gigoozens; Notropis spp., Hudsonius spp.) along with a variety of freshwater fish and …

Relationship Between Ratio Of Hybrid Sunfish To Their Parent Species And Latitude, Maxwell Kattner

Journal of Earth and Life Science

Hybrid sunfish of the Lepomis genus make up a generally small but notable portion of the population of sunfish in Minnesota lakes. Hybrid sunfish play a significant role in freshwater ecosystems across the United States. They are both morphologically and behaviorally distinct in some ways and similar in other ways to their parent species, causing them to both fill and compete with their parent species for niches occupied by multiple Lepomis species. Despite this, the ratio of hybrid sunfish to their parent species has never been properly explored. This study observed if the ratio of hybrid sunfish to their parent …

Coho Salmon (Oncorhynchus Kisutch) Response To Habitat Restoration Through Space And Time: Monitoring Growth, Survival, And Movement In A Restored Habitat Network, Carter Perez Adamson

Cal Poly Humboldt theses and projects

Despite the decline of coho salmon (Oncorhynchus kisutch), Prairie Creek, a tributary of Redwood Creek in northern California, remains a coho salmon stronghold. The restoration of juvenile coho rearing habitat was identified as a recovery objective in this watershed by the National Marine Fisheries Service. Among the restoration projects addressing this objective are an ongoing project on Prairie Creek and its tributary Skunk Cabbage Creek, and a prior effort on Strawberry Creek (a tributary of Redwood Creek’s estuary). Standard monitoring methods for assessing project success have limitations and may be improved by measuring salmon use of restored habitats …

Fisheries Research Report No. 359: Metropolitan Monitoring Program 2025, Alissa Tate, Claire B. Smallwood, Karina L. Ryan, Troy Matthews

Fisheries Research Reports

Ongoing monitoring of recreational fisheries in the Perth Metropolitan zone is essential to ensure the sustainable use of fisheries resources. Surveys of shore- and boatbased recreational fishers within the Metropolitan zone of the West Coast bioregion provide information on human dimensions and catch-per-fisher as well as mean length and weight of key recreationally caught species. For shore-based fishers, estimates of fishing effort, catch and harvest are also presented for key nearshore species. This information is used to support ongoing assessments for key nearshore species and the development and evaluation of harvest strategies and other management actions, such as for Australian …

Effectiveness Of Walleye Stocking In Winter Kill Lakes, Tyler Haus

Journal of Earth and Life Science

Winter kill events, marked by extensive fish mortality due to hypoxic conditions under the ice, are a common phenomenon in shallow eutrophic lakes, especially in the northern lakes in the northern United States. These events can drastically alter fish communities and often result in the elimination of top predators. Though these lakes will typically slowly bounce back to what they were in a couple of years. This study evaluates the effectiveness of walleye, Sander vitreus, stocking in lakes after a winter kill. For this study, four known winter kill lakes that are consistently stocked with walleye were studied. Pre- …

Size Structure Comparison Of Bluegill In Lakes With And Without Special Regulations, Jenna Lawin

Journal of Earth and Life Science

Lots of individuals have mixed feelings about special regulations for all sorts of game fish species such as northern pike Esox lucius, crappie Pomoxis spp., sunfish Lepomis spp., and so on. One species commonly sought after by many is bluegill Lepomis macrochirus. Bluegill are often deemed easy to find, catch, and clean. This study looks at three different categories of lakes (all lakes contain bluegill populations). The three categories are lakes with a five sunfish limit, lakes with a ten sunfish limit, and lakes without any special regulations. This study provides valuable insight into the size …

A Re-Evaluation Of Atlantic Bluefin Tuna (Thunnus Thynnus) Spawning Distribution In The Western Atlantic Ocean, David E. Richardson, Katrin E. Marancik, Malgorzata Adamus, Elizabeth A. Broughton, Robert K. Cowen, Trika Gerard, Christina M. Hernández, John J. Hoey, Joel K. Llopiz, Molly E. Lutcavage, Estrella Malca, Debra L. Palka, Lourdes Vásquez-Yeomans, Harvey J. Walsh, C. Michelle Willis, Glenn A. Zapfe

Biological Sciences Faculty Publications

There is currently a lack of consensus on the spatial, seasonal and decadal-scale patterns of Atlantic bluefin tuna (Thunnus thynnus) spawning in the western Atlantic Ocean. We compiled ichthyoplankton and reproductive data to characterize bluefin spawning patterns and the uncertainty in these patterns. Ichthyoplankton data indicates that bluefin spawn in the Gulf of America/Gulf of Mexico, northwest Caribbean Sea, north of the Bahamas, along the inshore edge of the Florida Current off the Carolinas and in the western Slope Sea. Reproductive studies identified these same spawning areas, as well as the Windward Passage and waters east of the …

Using Genetic Analysis To Infer Familial Relationships Of Westslope Cutthroat Trout In The Lower Priest River, Idaho, Kolby Emtman

EWU Masters Thesis Collection

The Westslope Cutthroat Trout (Oncorhynchus lewisi) is a native species of salmonid that holds both cultural and ecological significance in the Idaho Panhandle region of the United States. Within this region, the Priest River is a major contributor of migrant Westslope Cutthroat Trout to the Clark Fork Pend Oreille basin. This study aimed to estimate the proportion of juveniles that have at least one migrant parent, illustrate gene flow using juvenile half sibling relationships, and showcase varying levels of spawning success using juvenile full sibling relationships. Sampling of juvenile individuals occurred in 11 tributaries of the Priest River over …

Linked Lives In The Riverbed: Integrating Fish Host Dynamics, Community Structure, And Demography For Freshwater Mussel Conservation., Jonathan Patrick Frommeyer

Electronic Theses and Dissertations

Freshwater mussels are long-lived benthic invertebrates that play key roles in nutrient cycling, water filtration, and habitat stability in rivers and streams. Despite their ecological importance, they are among the most imperiled faunal groups in North America, with their persistence increasingly threatened by environmental degradation and disruptions to host–parasite dynamics. This dissertation integrates host ecology, community structure, and demographic modeling to assess population viability and guide conservation priorities for mussel species in Kentucky river systems. The first chapter introduces the ecological context and conservation urgency surrounding freshwater mussels. In particular, emphasizing the need for multi-scale approaches to understand how parasitic …

Stream Fish Assemblage Dynamics And Barriers To Aquatic Connectivity In The Ichawaynochaway Creek Watershed, Georgia, Usa, Jake R. Duhé

LSU Master's Theses

Stream fishes in the southeastern United States are adapted to hydrological disturbances such as droughts. However, this region is projected to experience increasingly frequent and severe disturbances that will elevate water demands given increasing agricultural and urban development. Further, road-stream crossings (RSCs) are abundant features in these streams that can exacerbate drought-mediated stream fragmentation and impede movements by many aquatic organisms, including fishes, when poorly constructed. These compounding effects may adversely affect the diversity and abundances of resident stream fishes, but their interactions remain poorly understood, warranting rigorous testing of how droughts and RSCs influence stream fish dynamics. I assessed …

Temporal Assessment Of Fish Communities In A South Central Plains Ecoregion Watershed, Tara L. Schnelting

ATU Theses and Dissertations 2021 - Present

Among South Central Plains ecoregion fish communities, there is limited knowledge of the importance of headwaters yet this information is needed to understand their role in fish communities. I addressed this gap by assessing seasonal changes in fish communities in headwater streams of the Moro Creek watershed, Arkansas. I conducted two studies pertaining to temporal fish community assessments: (i) utilize multi-season, community occupancy models to estimate μ (species probability), Ω (community occupancy mean), and p (detection probability) and (ii) utilize beta diversity (β) analyses to address the diversity across different scales in the headwaters of the Moro Creek …

Fisheries Management Paper No.286: Western Australian Octopus Resource Harvest Strategy, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

Harvest strategies for Western Australia’s (WA) aquatic resources are formal documents developed to support decision-making processes that ensure the outcomes are consistent with the principles of Ecologically Sustainable Development (ESD; Fletcher 2002a) and Ecosystem Based Fisheries Management (EBFM; Fletcher et al. 2012). Harvest strategies are a key component of all contemporary fishery management systems and a requirement for certification under the Marine Stewardship Council (MSC). The objectives of ESD are reflected in the objectives of the Fish Resources Management Act 1994 (FRMA).

This Octopus Resource Harvest Strategy (Harvest Strategy) has been developed and revised in line with the Harvest Strategy …

Marine Protected Species Identification Guide 2025, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Occasional Publications

The Western Australian aquatic environment is home to a number of species that are protected under international agreements and national or state legislation. Many of these species occur in areas where fishing takes place, sometimes resulting in interactions between fishers and protected species. An interaction is considered to be any physical contact between a person, fishing vessel or fishing gear and a protected species, including captures, entanglements and collisions.

This guide has been developed to help you identify some common marine protected species in Western Australia that you may encounter while fishing.

It has been divided into 5 sections:

• …

Size Of Age-0 Sander Vitreus Pre And Post Dreissena Polymorpha Infestation On Brainerd And Bemidji Area Lakes, Quady Bernu

Journal of Earth and Life Science

Walleye Sander vitreus is the Minnesota state fish and a vital predator fish in lake ecology. Zebra mussels, Dreissena polymorpha were first found in Minnesota inland lakes in the 1980’s. These mussels have had huge impacts on water clarity as well as phytoplankton and zooplankton population levels which affect how age-0 fish feed, especially a low light feeding predator fish like walleye. A study took place on age-0 walleye size and it supported the conclusion that age-0 walleye were negatively impacted by zebra mussels in Minnesota’s large lakes. The goals of this study were to determine how the size of …

Microsatellites Reveal The Population Genetic Structure Of Yellow Perch In Minnesota, Megan Boche

Journal of Earth and Life Science

When analyzing a population’s genetic makeup, looking at variation of individuals and populations is a crucial factor. The management of yellow perch will be aided by this information particularly in regard to stocking or relocation. Microsatellite loci were used to analyze the genetic population structure of yellow perch Perca flavescens within and among 29 sampling areas throughout Minnesota’s basins. Seven microsatellite DNA loci were evaluated, with heterozygosities ranging from 0.41 to 0.78. The Lower Mississippi basin samples showed higher numbers of alleles per locus and greater expected heterozygosities compared to other basins, with Lake Pepin (PEP) exhibiting the highest average …

Marine Heatwave Response Plan For Western Australia’S Wild Capture Fisheries And Aquaculture, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

The purpose of the Western Australian wild capture fisheries and aquaculture marine heatwave response plan (the Plan) is to document the Department’s approach for identifying and responding to the hazard of a marine heatwave on wild catch fisheries (commercial, recreational, charter and customary) and aquaculture resources within the geographic boundaries of WA. It provides risk reduction strategies and establishes best-practice processes for each stage of the hazard management and response continuum, ensuring that DPIRD is able to adequately prepare for, respond to, and recover from marine heatwave events. This Plan operates in conjunction with WA’s existing aquatic resource management framework, …

Habitat Use And Selection Of Silver Carp In The Lower Wabash River System, Coy B. Blair

Masters Theses

The spatial ecology of non-native species in invaded systems remains relatively poorly understood despite the importance of suitable habitat in the success of invasion. Silver Carp Hypophthalmichthys molitrix are a highly invasive non-native species with established populations throughout the Midwestern United States. Much research has focused on habitat use of bigheaded carp in large river systems, though invasion risk remains high in smaller systems, such as tributaries of the Great Lakes and the Ohio River. The Wabash River, a unique system in the Midwest, remains largely un-impounded and is comparable to many of the smaller riverine systems at risk of …

Crisis In The Current: A Proposed Study On The Impact Of Columbia River Basin Water Quality On Juvenile Chinook Salmon Survival, Olivia Buist-Thuillier

Pitzer Senior Theses

Salmon occupy a vital role in the ecosystem, economy, and indigenous culture of the Pacific Northwest of the United States, specifically within the Columbia River Basin. Of the five species of Pacific Salmon that live in the basin, Chinook salmon (Oncorhynchus tshawytscha) are the most widely commercially fished and are the largest. In recent years, Chinook Salmon populations have heavily declined from human influence. Rising temperatures from anthropogenic climate change, habitat destruction (dams, human presence), runoff from agricultural practices, and overfishing have all contributed to this decline. Because of their role as a keystone species and their cultural significance, there …

‘Who’S Your Daddy?’: Ddradseq Parentage In Broodstock-Offspring Pairs Of Diadema Antillarum In A Population Restoration Initiative, Bianca R. Rosendahl

Undergraduate Scholarship and Creative Works

In the early 1980s Diadema antillarum, or the long-spined urchin, was hit by a catastrophic mass mortality event across the western Atlantic and Gulf of Mexico, inclusive of the Florida Keys. The cause of this die-off event was likely triggered by a pathogen or environmental stressor that decimated native populations by up to 98%. The species has not yet fully recovered and is struggling with recruitment success which is why it may benefit from an ex-situ recovery program. In this study, I used single nucleotide polymorphisms (SNPs) to identify genetic variation and analyze parentage in a captive population of …

Size Structure Of Black Crappie And Bluegill In Northern, Eastern, Western, And Southern Minnesota, Ray Anderson

Journal of Earth and Life Science

Fish size structure is an important factor in a fishery population. Panfish such as black crappie Pomoxis nigromaculatus and bluegill Lepomis macrochirus play a major role in the health of fisheries. Five lakes from southern, northern, eastern, and western Minnesota were selected for analysis. Data were collected using standard sampling methods, including gill nets, electrofishing, and fyke nets. Length-frequency distributions were created to assess size structure in each region. Relative abundance was measured using catch per unit effort. Data analysis included a one-way ANOVA to compare Proportional Size Distribution (PSD) values and the distribution of fish sizes among regions. Chi-square …

Comparison Of Hoop Nets To Trap Nets In Sampling Panfish, Jayden R, Alsleben

Journal of Earth and Life Science

Panfish including bluegill Lepomis macrochirus and black crappie Pomoxis nigromaculatus are gamefish species of significance found in Minnesota. Hoop nets and trap nets are two types of gear that can be used to sample these fish. Fisheries managers and anglers alike are interested in the best tactics to capture panfish. The behavior of fish, including bluegill and black crappie, change throughout the sampling season and make it difficult to assume accurate representations. Trap nets have historically been adequate in sampling near shore populations, but questions surrounding the gear have allowed other options to be pursued. The objective of this study …

A Sample Of Fish Communities In Beaver Ponds Of Northern Minnesota, Reed Cumberland, Rose Kuhlmann

Journal of Earth and Life Science

The North American beaver Castor canadensis is an ecosystem engineer and a keystone species to the environment. Beaver inhabit ponds and construct dams to build ponds that provide habitat for certain fish. Little information is provided on the species of fish that live in beaver ponds. The objective of this study is to sample the fish communities in beaver ponds while comparing the effectiveness of two styles of minnow traps. Twelve beaver ponds were selected in the Bemidji area to be sampled. The quantity and species caught in each style of trap were recorded to compare effectiveness of each trap …

Does Depth Affect Zebra Mussel Length In Scalp Lake?, Zanden Mellen

Journal of Earth and Life Science

Since its first sighting in 1996, zebra mussels Dreissena polymorpha have been confirmed in hundreds of Minnesota lakes. Not only were they found in lakes, but they are also found in rivers too. With lack of effective treatments to impede their spread, zebra mussels continue to colonize new areas causing ecological as well as economic harm. The objective of this study was to see if there was a relationship between a zebra mussel length and the depth, they are found using shell length (mm) and depth (cm). The comparison of zebra mussel length and depth was done by performing a …

Tailwater Trout Population Dynamics, Connor Dylan Cunningham

Graduate Theses/Dissertations

Dams have been constructed throughout the world and provide several resources for humans (e.g., flood control, hydropower). These structures heavily alter the upstream and downstream environment. One consequence of these alterations is the creation of “tailwaters”, which can create cold-water habitat via hypolimnetic releases. In the southeast United States these tailwater environments are often managed for the recreational use of nonnative salmonids. The unnatural flow regimes of tailwaters affect the biotic and abiotic conditions and ultimately the dynamic rate functions (i.e., recruitment, growth, mortality) of the fish inhabiting them. As such, the goal of this research is to provide fisheries …

Exploring Coastal Plain Fish Ecology Across A Range Of Early-Life-History Traits And River Types, Bridgette Nicolosi

College of Graduate Studies: Theses & Dissertations

The ecological complexity of southeastern Coastal Plain rivers is reflected in the diversity of fish communities they support, yet the processes structuring early life dynamics remain poorly understood. This thesis explores the influence of environmental gradients on larval fish assemblage composition and American Shad (Alosa sapidissima) spawning phenology across two Georgia Coastal Plain river systems.

In the unregulated Ogeechee River, I investigated spatial and temporal variation in larval fish communities by comparing mainstem and tributary habitats to understand the role of tributaries in watershed-wide larval production. Larvae were collected biweekly from May to September 2024 at eight paired mainstem-tributary sites …

Pilbara Demersal Scalefish Resource Recovery Plan 2023- 2043 (Phase 1), Department Of Primary Industries And Regional Development, Western Australia

Fisheries Management Papers

The Pilbara Demersal Scalefish Resource (PDSR) includes over 60 demersal scalefish species. The resource is accessed by the Pilbara Trap Managed Fishery, Pilbara Fish Trawl (Interim) Managed Fishery, and the Pilbara Line Fishery (PTMF, PFTIMF & PLF respectively) as well as the recreational and charter fisheries.

The PDSR is managed in accordance with the North Coast Demersal Scalefish Resource Harvest Strategy (Harvest Strategy). The sustainability objectives of the PDSR are set out in the Harvest Strategy and monitored via the use of an indicator species approach, whereby the status of key species is considered representative of the status of the …