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Estimating Daily Growth Of Age-0 Channel Catfish In A Free-Flowing, Commercially Exploited Midwestern River, Kaleb B. Wood

Masters Theses

The larval stage in fishes is an important stage in the life history, as their survival dictates the ability of the population to sustain itself as an adult population. While there is a plethora of information available for juvenile and adult life stages of Channel Catfish (Ictalurus punctatus), very little is understood about their larval life stage. This study sought to determine overall density, growth rates, and size structure of cohorts of age-0 Channel Catfish during a study year on the Wabash River. In 2018, I sampled age-0 Channel Catfish using a benthic trawl from May to September. …

Population Demographics Of Channel Catfish In The Lower Wabash River, Valerie J. Thompson

Masters Theses

Inland fisheries are experiencing increasing demands due to anthropogenic stressors, especially within large river systems that support both recreational and commercial fisheries. Riverine species are sensitive to habitat degradation, species introductions, and exploitation, so continued monitoring and management of these communities are vital to maintain abundance and diversity within these systems. The North American catfish family, Ictaluridae, supports both recreational and commercial fisheries throughout the United States. Channel Catfish Ictalurus punctatus are heavily studied and managed compared to other sport catfishes in this family because of their economic and ecological significance. One important Channel Catfish fishery exists in the lower …

Collaborative And Engaged Research To Strengthen Equity And Adaptive Governance In Co-Managed Fisheries, Gabrielle V. Hillyer

Electronic Theses and Dissertations

Small-scale, co-managed fisheries are found throughout the world and often represent intertwining cultures, societies, communities, economies, institutions, and governments. They face complex issues, derived from ecological and social sources. Solving these issues requires diverse expertise, often developed through engaged methodologies which can facilitate collaborative solution creation between researchers, community members, and others. In this dissertation, I demonstrate the benefits of these engaged methodologies and review how they, when coupled with anticolonial approaches to research, can create more equitable solutions to complex issues. This dissertation focuses on multiple projects within the wild clam fishery in Maine including: (1) the creation of …

Genetic Effects Of Anthropogenic Disturbance On Native Charrs, Brad Erdman

Electronic Theses and Dissertations

Artificial propagation has been utilized for over a century to offset anthropogenic declines of abundance for many fishes. Complex and poorly documented histories of habitat degradation and stockings have resulted in considerable uncertainty regarding whether contemporary populations are of native, hatchery, or mixed origins. This uncertainty is problematic as it precludes prioritizing the conservation of native populations that are postulated to possess local adaptations and greater evolutionary potential. Population genetics can assess the relative reproductive contributions of previous stocking events and in this dissertation I apply these methods to four empirical studies of native charr (genus Salvelinus) that have …

Fishing Out Nutrients: The Spatiotemporal And Ecological Dynamics Of Fishery-Based Nutrient Extraction, Adrián A. González Ortiz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Marine fisheries are one of the most impactful human activities on the planet. Since the 1950s, marine fisheries have removed billions of metric tons of marine biomass leading to substantial declines in many fish populations. Among their impacts, we have begun to investigate the role of fisheries in disrupting marine nutrient cycles. Specifically, removing biomass can change nutrient cycles by reducing the amount of nutrients stored within animal biomass.

No studies have investigated the large-scale geographical and ecological contexts of nutrient removal by fisheries over a large timescale. For my thesis, we compiled data on fishery-targeted organisms' carbon, nitrogen, and …

An Exploration Of Palauan Fishing Methods And Fisheries: A Study For The Conservation Of Dugongs, Mia Glover

Electronic Theses and Dissertations

The dugong (Dugong dugon) is an important marine mammal in Palau. However, current population dynamics are not well understood. This study aimed to connect scientific data with local knowledge by examining the social implications of changing fishing methods and their impact on dugong population dynamics in the face of climate change and fisheries commercialization. Through interviews with local fishers, it was found that destructive fishing methods like trawling and long lining have led to habitat loss and degradation for dugongs. These tactics, driven by economic factors, have disrupted the delicate balance between human activities and the preservation of dugong habitats, …

Understanding Dietary And Thermal Influences On Invasive Cichlids In Puerto Rico Reservoir Systems, Jacob A. Moreland

Theses and Dissertations

Jaguar Guapote (Parachromis managuensis) and Amphilophus spp. were assessed for effects of temperature on standard metabolic rate (SMR) and lower dissolved oxygen tolerance (LDOT), efficacy of gastric lavage for diet analysis, and diet in Puerto Rico reservoirs. Fish were acclimated to 22°C, 28°C, and 34°C and SMR and LDOT were measured using intermittent respirometers. Jaguar Guapote acclimated to 34°C had the greatest SMR, with 22°C and 28°C having similar SMR values. Amphilophus spp. acclimated to 28°C were similar to fish acclimated at 22°C and 34°C. Fish were resilient to high temperatures, losing equilibrium more rapidly at the coldest temperature, 22°C. …

Fish Community Impacts And Conservation Implications Of A Novel Barrier On The San Juan River, Utah, Zachary T. Ahrens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Stream fragmentation and non-native species introductions are among a suite of anthropogenic disturbances shaping the structure and function of freshwater ecosystems. The impacts of such alterations contribute to the global decline of stream fish biodiversity and may be synergistic in their effects. For example, the Colorado River basin’s unique native fish assemblage is imperiled not only by numerous dams and diversions, but also by threats of predation and competition for limited resources from non-native fish species. On the San Juan River, Utah, a recently formed fish barrier prevents upstream movement of native and non-native fish. The goal of this project …

The Influence Of Range Shifts And Wind Energy On The Atlantic Surfclam (Spisula Solidissima) And Ocean Quahog (Arctica Islandica) Fisheries On The U.S. Outer Continental Shelf, Stephanie Stromp

Master's Theses

The Atlantic surfclam, Spisula solidissima, is a biomass dominant bivalve of the Northwestern Atlantic. The surfclam’s historic range extended from Cape Hatteras to Georges Bank, but recent decades of warming bottom water temperatures have caused the surfclam to shift its range to cooler waters north and offshore within the range of the ocean quahog, Arctica islandica. An ecotone now exists over much of the offshore range of the surfclam in which surfclams and ocean quahogs co-occur. Regulations prohibit fishers from landing both species in the same catch, limiting fishing to locations where the target species can be sorted …

American Eel (Anguilla Rostrata) And Other Fishes As Surveyed By Environmental Dna In The Bronx River And Hudson River Watershed, Sam C. Chin

Dissertations, Theses, and Capstone Projects

Mounting an effective response to the threats faced by freshwater fish may require expansions to aquatic biomonitoring in excess of what is feasible using the capture-based survey techniques currently relied upon by natural resource managers. Methods for analyzing environmental DNA (eDNA) are emerging as a minimally invasive and cost-effective approach for surveying fish and other organisms. By detecting taxon-specific DNA sequences recovered from environmental samples (e.g. water, sediment), eDNA methods are able to infer species presence from samples that can be collected rapidly with simple equipment. In many cases, eDNA detection rates of fish species have been shown to meet …

Field Assessment Of The Pervious Oyster Shell Habitat: Enhancement Of Intertidal Habitat For The Eastern Oyster And Associated Nekton In Northeast Florida, Hunter Mathews

UNF Graduate Theses and Dissertations

A dramatic global decline in oyster reef habitat has led to widespread deployment of oyster restoration projects. Efforts are underway to move away from polluting methods like plastic mesh bags in oyster deployments. Additionally, increasing pressure on our estuaries from recreational boat wakes and intensified storms requires more robust structures for shoreline protection. The “Pervious Oyster Shell Habitat” (POSH) is a novel artificial reef structure composed of oyster shell bound by a thin layer of Portland cement, into the shape of a dome. The structure’s makeup greatly reduces its environmental impact, while providing quality substrate for provision of oyster reef …

Use Of Foreign Edna Tracers To Resolve Site- And Time-Specific Edna Distributions In Natural Streams, Braden A. Herman

Cal Poly Humboldt theses and projects

Substantial uncertainty in how to interpret eDNA observations motivates a need for a technique to effectively and efficiently measure of system- and time-specific eDNA distributions. Using a technique to robustly calibrate eDNA dynamics in a given system would improve established eDNA methods such as presence and absence and has the potential to refine estimates of organism abundance using eDNA concentration that are less well understood. Particles of eDNA are present in a wide variety of size and type resulting in varying transport dynamics, persistence, decay, among others. This variation likely makes eDNA transport more complex than that of conservative tracers …

Preliminary Trials To Assess Bycatch Reduction Potential For Deep-Set Pelagic Longline Gear In The U.S. Atlantic Fishery, Sean T. Wilms

All HCAS Student Capstones, Theses, and Dissertations

The U.S. Atlantic pelagic longline fishery uses a shallow-set gear configuration to primarily target swordfish (Xiphias gladius) and yellowfin tuna (Thunnus albacares) at depths of around 75-100 m. However, the fishery has been the subject of several bycatch reduction regulations due to incidental catch and mortality of sea turtles, seabirds, marine mammals, and istiophorid billfishes. An alternative deep-set technique, used by the U.S. pelagic longline fishery based in Hawaii and several non-U.S. fleets, differs from the shallow-set pelagic longline gear by deploying a greater length of mainline per unit distance using a mechanical line shooter, resulting in a deeper catenary …

Age, Growth, Foraging, And Trophic Ecology Of Bigeye (Thunnus Obesus) And Yellowfin (Thunnus Albacares) Tuna In Continental Shelf And Slope Regions Of The Northeast U.S., Riley S. Austin

Electronic Theses and Dissertations

Traditional stock assessments require, in part, accurate knowledge of growth relationships to estimate a variety of aspects involved in population conservation management of exploited species. In addition, the local distribution and condition of top pelagic predators is driven by detection of abundant forage aggregations and along with traditional stock assessments, should be considered for effective management of marine populations. Empirical analyses of these data are severely lacking for bigeye (Thunnus obesus) and yellowfin (Thunnus albacares) tuna in the Atlantic Ocean, especially for the former. Given historical studies’ observations of these two top predators use as biological samplers due to their …

Linking Local Knowledge & Community Science In Support Of Coastal Marine Stewardship, Sarah Risley

Electronic Theses and Dissertations

In the last two decades, there has been a shift towards more integrated, ecosystem-based approaches to marine management, including fisheries. At the same time, there have been calls for greater inclusion of diverse perspectives in conservation science and practice. For these reasons, there is renewed interest in the integration of indigenous and local knowledge into science, management, and environmental decision making. Despite these developments, local knowledge often is poorly integrated or treated as something of lesser value than knowledge generated or curated by professional researchers. Novel methods that integrate social and ecological data and prioritize local knowledge and community-based approaches …

Bottom-Up Effects Of Degradation Outweighs Stabilizing Potential Of Omnivores, Hannah Marie Moore

Murray State Theses and Dissertations

Anthropogenic activities have led to degradation in streams throughout much of Western North America. In particular, cattle grazing has led to a loss of riparian vegetation resulting in higher water temperatures and an increase in nutrient runoff. The effects of degradation on food quality and quantity for aquatic consumers could have large implications for stream communities. Since omnivores feed at multiple trophic levels, they may be resilient to altered food webs, which may allow them to stabilize communities in degraded environments where resources have been reduced. To test the hypothesis that omnivores positively impact community stability in degraded conditions, I …

A Characterization Of The Sandy Beach Surf Zone Fish Community And Their Ecology In Northern California And The Effects Of Marine Protected Areas, Katie B. Terhaar

Cal Poly Humboldt theses and projects

Historically written off as dull and homogenous, the dynamics of the sandy beach surf zone remains under studied world-wide. Northern California has been no exception to this global standard, as the sandy beach surf zone ecosystem in this region has yet to be characterized, and the effect of Marine Protected Areas (MPAs) on the fish and macroinvertebrate community fully ascertained.

Considered data-poor by local wildlife officials, commercially, recreationally and culturally important Amphistichus rhodoterus (redtail surfperch) and common Hyperprosopon ellipticum (silver surfperch) utilize the sandy beach surf zone in Northern California. Little is known about the effect of various environmental factors, …

Foraging Ecology Of Sexually-Dimorphic Marine Generalist Predators: Describing Stellar Sea Lion Diet Along The Northern Washington Coast, Zöe Kathryn Lewis

WWU Graduate School Collection

Understanding generalist predator impact on prey populations requires an understanding of predator diet composition, foraging ecology and specialization, all of which may vary over spatial and temporal scales. Steller sea lions (Eumetopias jubatus) are large, sexually dimorphic, generalist predators that may have different roles in the ecosystem based on sex. However, the variation between individuals within a population, or intrapopulation feeding diversity of Steller sea lions has not been examined. In this study, I describe the diet of Steller sea lions along the northern coast of Washington between December 2020-August 2021 using DNA metabarcoding, hard parts analysis, and qPCR sex …

Patterns Of Habitat Use And Trophic Structure In Turtle Grass (Thalassia Testudinum)-Dominated Systems Across The Northern Gulf Of Mexico, Christian Hayes

Dissertations

Seagrass structural complexity is a primary driver of nekton recruitment and faunal community structure. Few studies, however, have quantified the role of seagrass complexity on habitat use and trophic structures over large spatial scales. A large-scale simultaneous survey was conducted to assess relationships of multiple seagrass morphological complexity metrics to nekton habitat use, trophic dynamics, and blue crab (Callinectes sapidus) growth and mortality across the Northern Gulf of Mexico. Seagrass morphological and nekton community characteristics depended on site and season, and regional variation in seagrass morphology was an important driver of juvenile nekton abundance, species richness, beta diversity, …

Applications And Mechanisms Of Near Infrared Spectroscopy For Age Estimation In Otoliths Of Red Snapper Lutjanus Campechanus, Michelle S. Passerotti

Theses and Dissertations

Near infrared spectroscopy (NIRS) is a light spectroscopy method useful for non-invasively discriminating and quantifying chemical composition of a wide variety of substances. Recently-developed applications of NIRS to fish age estimation across a range of taxa have sparked intense interest in exploring the feasibility of its use for rapid age estimation in fisheries population management. In this pursuit, development of species-specific calibration models relating traditionally-derived age estimates (i.e., those estimated from growth band counts) to NIR spectral signatures from ageing structures is required to derive predictive models that can then estimate age from rapid scans of whole ageing structures alone. …

A Spatiotemporal Assessment Of Fish Assemblage Response To Land-Use Change And The Evaluation Of Edna Metabarcoding For Describing Diverse Fish Communities, Timothy M. Owen

Theses and Dissertations

Fish assemblages are often assessed as a biological proxy for environmental health. While humans value healthy environments for the ecosystem services and recreational opportunities they provide, it is increasingly evident that such resources can be paradoxically degraded by anthropogenic activities. In this investigation, we studied the relationship between different intensities of anthropogenic land-use change and habitat-driven fish assemblage response across multiple spatiotemporal scales. Secondarily, we explored the efficacy of eDNA metabarcoding against conventional electrofishing techniques for the purpose of describing complete fish communities. This study was conducted in the Tuckahoe Creek basin near Richmond, Virginia. This James River tributary serves …

A Lake Divided: Regional Shifts In Trophic Niche Structure Of Lake Powell Fishes Corresponding To The Invasion Of Quagga Mussels, Nathan Richard St Andre

Theses and Dissertations

Introduced species can become invasive and cause catastrophic alterations to the system they invade. Both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) have caused significant ecosystem alterations wherever they have invaded. These Dreissena species have caused changes in water quality and biodiversity and have disrupted energy pathways which can have cascading effects on other trophic levels. Recently quagga mussels invaded Lake Powell, a reservoir located in the southwestern USA, creating the possibility of a trophic cascade that could alter energy flow in the reservoir and change the trophic niche structure of the fishes in the lake. However, due …

Otolith Age Validation And Microchemical Investigation Of The Northern Stock F Atlantic Black Sea Bass (Centropristis Striata), Elise R. Koob

Graduate Masters Theses

Black sea bass (Centropristis striata) is a demersal marine species that supports extensive commercial and recreational fisheries along the Atlantic coast. A recent expansion into the Gulf of Maine raises questions about this species’ movement and population dynamics in the region. Additionally, the 2016 catch-at-age stock assessment model for the northern stock incorporated a population split at the Hudson Canyon. Though this model better accounts for differences in populations, several issues remain. First, validation of the otolith ageing technique for this stock is incomplete; and, second, the origin of fish that moved into the northern ranges of the Gulf of …

Louisiana Southern Flounder: Commercial And Recreational Trends, David Russell Smith

LSU Master's Theses

Southern Flounder (Paralichthys lethostigma) is a coastal flatfish species that supports recreational and commercial fisheries throughout Louisiana. The recreational and commercial sectors of the Southern Flounder fishery in Louisiana both lack current information that profiles the fishery’s ability to meet stakeholder interest. This project characterized the Louisiana Southern Flounder fishery through an evaluation of fishery-dependent data and a survey of coastal Louisiana anglers.

Fishery-dependent data was gathered to characterize the recreational and commercial Southern Flounder fisheries in Louisiana. This study had three objectives for this evaluation: 1) modeling landings data to evaluate any trends, 2) examine the seasonality of landings, …

Fish Community Composition And Structure Near A Freshwater River Diversion In Southeastern Louisiana, Rachel L. Snider

LSU Master's Theses

Gulf of Mexico estuaries, particularly in Louisiana, are among the world’s most productive, with landings of commercially- and recreationally-important species exceeding all other contiguous US states. Coastal wetlands are disappearing at an alarming rate because they have been impounded from Mississippi River water and sediment. Although controversial, one proposed solution is to re-route the Mississippi River through diversions and siphons to supply the freshwater and sediments necessary to rebuild vanishing wetlands, particularly in Barataria Bay and Breton Sound, LA. This strategy is one approach outlined in the Louisiana Coastal Master Plan. This project aimed to describe the composition and structure …

Examining The Northern Shrimp Fishery In A Changing Gulf Of Maine, Ashley N. Charleson

Electronic Theses and Dissertations

Northern Shrimp (Pandalus borealis) once supported a key commercial fishery in the State of Maine. Since its closure in 2013, the stock has remained in a particularly vulnerable state following recruitment failure, overfishing, and rising water temperatures. Furthermore, without this source of supplemental income, local fishermen have also experienced financial stress following unstable fishing conditions in other fisheries. The collective goal of this research project was to assess factors impacting the feasibility of reopening and maintaining this vulnerable winter fishery. These goals are addressed over 4 chapters. Chapter two offers insight regarding what is most often omitted from the regulatory …

Managing Resilience In A Changing World: A Multiscale Analysis Of Fisheries Governance Challenges, Marina Cucuzza

Electronic Theses and Dissertations

Fisheries are complex social-ecological systems comprised of fish, humans, the institutions they create, and the broader ecological and social systems within which they are embedded. Changing ocean conditions, declines and shifts in key species, and loss of working waterfront infrastructure are among the many threats to the longevity of fisheries and fishing communities worldwide. A resilience approach to fisheries governance is increasingly recognized as key to sustaining coastal systems and the human communities that depend on them in the face of mounting socioeconomic and environmental challenges. Here I define resilience as the capacity of a system to withstand disturbances without …

An Analysis Of Dredge Efficiency For Surfclam And Ocean Quahog Commercial Dredges, Leanne Poussard

Master's Theses

Between 1997 and 2011, The National Marine Fisheries Service conducted 50 depletion experiments to estimate survey gear efficiency and stock density for Atlantic surfclam (Spisula solidissima) and ocean quahog (Arctica islandica) populations using commercial hydraulic dredges. The Patch Model was formulated to estimate gear efficiency and organism density from the data. The range of efficiencies estimated is substantial, leading to uncertainty in the application of these estimates in stock assessment. Analysis of depletion experiment simulations showed that uncertainty in the estimates of gear efficiency from depletion experiments was reduced by higher numbers of dredge tows per experiment, more tow overlap …

Patterns In Size Distribution And Catch Of Rockfish (Sebastes Spp.) In Fisheries-Independent And Fisheries- Dependent Hook-And-Line Surveys On The Central Coast Of California, Rose Elizabeth Dodgen

Master's Theses

Stock assessments are statistical models which characterize the state of a population of fish. Data for stock assessment models of West Coast nearshore groundfish come largely from fisheries-dependent sources. Incorporating fisheries-independent data would increase data availability. A potential source of fisheries-independent data which is comparable to existing fisheries-dependent data is the California Collaborative Fisheries Research Program (CCFRP), a Marine Protected Area (MPA) monitoring study. We are interested in understanding the context in which CCFRP could be implemented into assessments of nearshore groundfish, specifically rockfish. To investigate this, we used management-relevant metrics to examine three questions concerning the implementation of CCFRP …

Aging Techniques & Population Dynamics Of Blue Suckers (Cycleptus Elongatus) In The Lower Wabash River, Dakota S. Radford

Masters Theses

The Blue Sucker, Cycleptus elongatus, occurs in large rivers primarily in the Mississippi River basin. Their imperiled status has called attention to the need for its management and protection. Estimating age is crucial for directing management, but past studies have varied in their choice of hard structure, resulting in uncertainty regarding the basic life history of this species. Because the Wabash River Blue Sucker population may be one of few surveyable populations with high abundance and successful reproduction, their demographics can provide a benchmark against which threatened populations can be compared. We harvested Blue Suckers (n = 168) …