Aquaculture and Fisheries Commons^™

Habitat Use Of Blacktip Sharks (Carcharhinus Limbatus) At Fishing Piers, Kelsey L. Spencer

Electronic Theses and Dissertations

Blacktip sharks (Carcharhinus limbatus) can be observed near fishing piers throughout the summer along the northeast coast of South Carolina. These piers attract and support a wide variety of potential prey and sharks are able to forage on fishers’ discards with minimal energetic cost. I tagged 12 blacktip sharks with acoustic transmitters, monitored piers with acoustic receivers, and conducted pier-creel surveys to determine the habitat use of blacktip sharks at fishing piers, factors that influenced residence time and presence/absence at piers, and any cyclical patterns in visits to piers. Data were analyzed with pier association indices (PAI), mixed models, and …

Sea Lamprey (Petromyzon Marinus) As A Functional Link Between Marine And Freshwater Ecosystems, Daniel M. Weaver

Electronic Theses and Dissertations

Anadromous sea lamprey Petromyzon marinus are native to Atlantic coastal systems and serve as a functional link between marine and freshwater ecosystems. Sea lamprey spend 1–2 years in the ocean parasitizing marine vertebrates before migrating into freshwaters during the spring to spawn. There they construct nests, spawn, then die shortly afterwards. Larvae hatch, bury into fine sediments and reside in streams for generally 6–8 years, but up to 14. Larvae then undergo metamorphosis, a non-feeding period characterized by a series of physical and physiological changes. The juveniles (macropthalmia) then migrate to the ocean to begin the parasitic juvenile phase.

Historically, …

Investigating Factors Contributing To Reduced Embryo Survival In Farm Raised Atlantic Salmon, Salmo Salar L., Leeanne Thayer

Electronic Theses and Dissertations

Embryo mortality of Atlantic salmon, Salmo salar Linnaeus 1758, has been increasing for more than a decade in the State of Maine, a leading producer of this species in the United States. Increasing embryo mortality not only creates a financial bottleneck for farms but also prevents the sale of surplus eggs as an additional source of revenue. Blood and egg samples were collected at three Maine Atlantic salmon farms from female broodstock at the time of spawning over a 2-year period. Correlative factors for reduced embryo survival were investigated by measuring egg and maternal plasma concentrations of 17-estradiol (E2), 11-ketotestosterone …

Measuring Fertilization In Populations Of Sea Scallop (Placopecten Magellanicus): Developing And Testing Methods In The Laboratory And Field, Skylar Bayer

Electronic Theses and Dissertations

Most marine organisms are broadcast spawners, releasing their sperm and eggs into the water column. Methods of measuring in situ fertilization have proven successful with a few model species, which are reviewed in my introductory chapter. However, many commercially exploited species, such as the sea scallop Placopecten magellanicus, have been neglected. Sea scallop populations have greatly increased from fishing closures, but the mechanism behind this response is uncertain, particularly in regard to fertilization. In this dissertation I developed a methodology of measuring fertilization success and spawning events of P. magellanicus, tested it in laboratory and field settings, and …

Go With The Flow: Patterns Of Connectivity In Low Dispersal Coral Reef Gobies (Coryphopterus Spp.) Throughout The Western Atlantic, Daniel Volk

Electronic Theses and Dissertations

Gene flow is an integral biological process that can mediate speciation. While many consider the ocean to be an open environment, there are many barriers that limit gene flow, particularly in the western Atlantic. I analyzed data from two widespread, coral reef fishes, the bridled goby (Coryphopterus glaucofraenum) and sand-canyon goby (C. venezuelae), throughout their range in the western Atlantic. Using two genetic datasets, mitochondrial DNA (mtDNA) and genomic SNPs, I investigated the evolutionary history of these species and inferred the location and strength of putative barriers. My results suggest that several unique lineages have genetically diverged from one another …

Measuring Aquatic Organism Responses To Grassland Restoration: Does The Field Of Dreams Really Exist?, David A. Schumann

Electronic Theses and Dissertations

Landscape homogenization and the degradation of riparian areas has greatly impaired stream ecosystems throughout North America. Conservation programs may repair riparian ecosystems to indirectly improve water quality and instream habitat heterogeneity in hopes to elicit biological responses. However, focused manipulations on isolated stream fragments have rarely achieved biological goals. Prairie streams with restored riparian areas were appraised (chemical, physical, and biological variables) to quantify the indirect effects of prevalent grassland conservation practices on aquatic resources. Riparian rehabilitation, via passive methods, promoted bank-stabilizing vegetation along all conservation stream reaches. Riparian vegetation and function quickly recovered from previous agricultural disturbances at conservation …

Indexing Walleye Recruitment In Eastern South Dakota Natural Lakes, Todd M. Kaufman

Electronic Theses and Dissertations

Because of the popularity of Walleyes and the need for recurrent supplemental stockings, substantial resources are allocated to their management in eastern South Dakota. For nearly 20 years, fall night electrofishing has been used to monitor age-0 Walleye population parameters, and index future year-class strength in select waters but with limited evaluation. Additionally, knowledge of recruitment patterns and factors that influence those patterns were of interest. Thus, the objectives of this study were: 1) to determine the utility of fall electrofishing age-0 Walleyes to index future year-class strength; 2) to explore whether measures of fall age-0 body size or condition …

Growth Potential And Genetic Diversity Of Yellow Perch In South Dakota, Alex J. Rosburg

Electronic Theses and Dissertations

Yellow Perch Perca flavescens represent a valued sport fish throughout their range and are an important prey species for piscivorous fishes. In South Dakota, two distinct population types of Yellow Perch have been characterized that differ in growth, survival, and recruitment patterns. Fast growth populations exhibit high growth rates, high mortality, low population density, and inconsistent recruitment. In contrast, slow growth populations are characterized by reduced growth rates, low mortality, high population density, and relatively consistent recruitment. The role of genetics in contributing to these population characteristics is currently unknown. To address these questions, I used high-throughput restriction-site associated DNA …

Invertebrate Prey Selectivity Of Channel Catfish (Ictalurus Punctatus) In Western South Dakota Prairie Streams, Erin D. Peterson

Electronic Theses and Dissertations

Benthic invertebrates are an important resource for aquatic consumers and should be considered in management of sportfish populations as a factor influencing fishery health. Our study seeks to draw a relationship between invertebrate prey availability and the Channel Catfish Ictalurus punctatus fishery of western South Dakota through diet analysis, but invertebrate surveys in the area have not focused on invertebrates as a prey source. Our objectives were to characterize patterns in availability of the invertebrate prey base in five major river basins, and to evaluate the effects of availability on Channel Catfish prey selectivity and condition. Invertebrates were collected at …

Development And Application Of A Fish-Based Index Of Biotic Integrity For Lakes In Eastern South Dakota, Daniel T. Nelson

Electronic Theses and Dissertations

The Index of Biotic Integrity (IBI) was developed to summarize the impact of watershed and water quality degradation to biotic communities and help to provide a more complete picture of water quality changes that are not captured in traditional physical and chemical measurements. In 2014, nearly 15% of South Dakota lakes did not meet their designated beneficial uses based on water quality measures but the impacts to the fish communities are unknown. The goal of this study was to develop a fish-based IBI for eastern South Dakota lakes by addressing three specific objectives:
1) Determine whether an IBI could be …

An Evaluation Of Nitrogen Supplementation And Processed Soy Fractions On The Performance Of Cultured Fishes, Brandon M. White

Electronic Theses and Dissertations

World population growth has resulted in an increased demand for a sustainable food supply. This rapid growth coupled with an increased per capita consumption of seafood, has resulted in many of the world’s marine fisheries being over-exploited in an effort to meet the global demand for seafood. Aquaculture has attempted to fill the supply and demand gap created by the dwindling supply of fish in the world’s oceans. Fishmeal (FM) has traditionally been the primary protein ingredient in aquafeeds fed to farm-raised fish, however its unstable supply and increasing price have driven researchers to identify alternative protein sources. Soybean meal …

Effects Of A Large-Scale Habitat Enhancement Project On Largemouth Bass Behavior, Feeding, And Growth In Grand Lake, Texas, Chance Kirkeeng

Electronic Theses and Dissertations

The quality of habitat, or the environment suitable for an organism to survive and reproduce, is often described by the type of features present and the quantity and condition of such features. Habitats in many ecosystems are declining and the loss of important habitats likely affects the success of organisms reliant upon those features. Habitats in reservoir ecosystems are especially at risk because of aging processes that are degrading reservoir habitats at faster rates than habitats in other ecosystems. Habitat enhancement projects are one tool used to combat the effects of aging reservoirs but the benefits of these management actions …