Aquaculture and Fisheries Commons^™

Tracing Atlantic Sea Scallops Using Radio Frequency Identification (Rfid) Technology, Will Shoup

Dissertations, Theses, and Masters Projects

Traceable seafood can be linked back to its origin and method of catch. Improving the traceability of marine organisms involves establishing a transparent Chain of Custody (CoC) by collecting data at checkpoints throughout the supply chain, from ship to shore to store. This report explores the feasibility of integrating Radio Frequency Identification (RFID) technology into the United States Atlantic sea scallop (Placopecten magellanicus) fishery in order to improve traceability. This report serves as a forward-looking evaluation of RFID technology that is intended to inform interested stakeholders of its functionality and capabilities. It is not intended to serve as a management …

Improving Observation, Assessment, And Management Of Atlantic Coastal Sharks, Cassidy Dawn Peterson

Dissertations, Theses, and Masters Projects

Coastal sharks represent a group of stocks for which observation, assessment, and management are particularly challenging. Large distributional ranges, complex migratory behavior, low economic value, and relatively few observations in fishery independent surveys hinder relative abundance estimation. Assessing stock status of coastal sharks is encumbered by limited data availability, data quality, and knowledge of life history strategy. Further, coastal sharks are challenging to manage due to their slow intrinsic population growth rates, competing stakeholder interests, history of overexploitation, and in some cases, subjection to international exploitation. This dissertation aimed to improve the capacity to observe relative abundance of coastal sharks. …

Recruitment And Post-Settlement Mortality Of The Soft-Shell Clam, Mya Arenaria, Shantelle Landry

Dissertations, Theses, and Masters Projects

The soft-shell clam, Mya arenaria, is a benthic, filter-feeding, infaunal clam typically found in intertidal and shallow subtidal waters. Chesapeake Bay stocks of M. arenaria have been depleted since the 1960s due to various factors including predation, temperature, low recruitment, habitat loss, disease mortalities, and commercial harvest. As an important prey item for many commercial species, low abundances of these clams are mostly the result of the voracious appetite of the blue crab, Callinectes sapidus. In addition to predation, summer water temperatures in the Chesapeake Bay are likely driving the low abundances of M. arenaria, as water temperatures commonly surpass …

Dealing With Many Species: Improving Methodology For Forming And Assessing Species Complexes, Kristen Omori

Dissertations, Theses, and Masters Projects

In the United States, the Magnuson-Stevens Reauthorization Act mandates that all federally fished species must have catch limits, which can be challenging for data-limited species. One approach is to assess and manage a group of species with similar life history characteristics, vulnerability to the fishery, and overlapping geographic distributions in a single management unit, or a complex (i.e., stock or species complex). Using the Gulf of Alaska (GOA) Other Rockfish complex as a case study, the main goals of this dissertation are five-fold: 1) review species complexes in the United States; 2) compare multivariate techniques for assigning species to complexes; …

Investigating Economic Costs Of Derelict Blue Crab Callinectes Sapidus Pots And Preferred Mitigation Solutions In The Chesapeake Bay, James Delbene

Dissertations, Theses, and Masters Projects

Derelict fishing gear, particularly pots or traps, occupy waters worldwide and cause negative ecological and economic impacts. Derelict pots persist throughout Chesapeake Bay, the largest estuary in the U.S., that supports a valuable commercial fishery for the blue crab Callinectes sapidus. Chesapeake Bay is responsible for 30-40% of U.S. commercial blue crab harvests. Yet, few studies have quantified the impacts of derelict pots on harvest or the perceptions of commercial fishers on derelict pot mitigation activities in this predominantly pot fishery. This thesis examined the impacts of derelict pots on harvest in a field experiment and worked with commercial fishers …

Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram

Dissertations, Theses, and Masters Projects

All estuarine crabs have two larval stages, the zoea and the megalopa. Zoeae are entirely planktonic, whereas megalopae begin as plankton before beginning to search for settlement substrates as late stage megalopae. At both stages, crab larvae are subject to environmental conditions of the estuary. With changing environmental conditions due to anthropogenic activities and climate change, an understanding of how these planktonic larvae respond to environmental conditions is necessary for understanding subsequent larval supply to benthic populations and implication for fisheries management and habitat restoration. For this dissertation, I: 1) analyzed long-term timeseries in the lower Chesapeake Bay for spatial …

Improving Stock Assessments And Management Advice For Bluefin Tunas And Other Highly Migratory Species, Lisa Elma Ailloud

Dissertations, Theses, and Masters Projects

For years bluefin tuna has been the poster child for overfishing and poor management. However, recent improvements in data collection, catch monitoring and international cooperation are providing an opportunity to reverse the perception of a fishery that is doomed to collapse. Stock assessments are conducted routinely to monitor the abundance and productivity of exploited fish stocks so managers can determine how many fish can be sustainably harvested each year. Should a stock be declared overfished or under-going overfishing, the science behind stock assessments also equip managers with the knowledge necessary to make decisions about what short-term and long-term management measures …

Extensions And Applications Of Mean Length Mortality Estimators For Assessment Of Data-Limited Fisheries, Quang C. Huynh

Dissertations, Theses, and Masters Projects

For data-limited fisheries, length-based mortality estimators are attractive as alternatives to age-structured models due to the simpler data requirements and ease of use of the former. This dissertation develops new extensions of mean length-based mortality estimators and applies them to federally-managed stocks in the southeastern U.S. and U.S. Caribbean.

Chapter 1 presents a review of length-based methods from the literature. Common themes regarding the methodology, assumptions, and diagnostics in these length-based methods are discussed. In Chapter 2, a simulation study evaluates the performance of the length-converted catch curve (LCCC), Beverton-Holt equation (BHE), and Length Based-Spawner Potential Ratio (LB-SPR) over a …

Ecosystem Services Of Restored Oyster Reefs In A Chesapeake Bay Tributary: Abundance And Foraging Of Estuarine Fishes, Bruce William Pfirrmann

Dissertations, Theses, and Masters Projects

Oyster reef restoration may enhance the production of ecologically or economically important fish species, an ecosystem service, by providing refuge and foraging habitat. Predicting the effects of oyster habitat restoration on fisheries production in Chesapeake Bay requires a better understanding of fish habitat use, trophic dynamics, and the processes leading to production on a habitat-scale. The objective of this thesis was to evaluate the influence of restored subtidal oyster reefs on the abundance and foraging patterns of mobile estuarine fishes. Specifically, I compared the 1) abundance, 2) stomach fullness, 3) diet composition, and 4) daily consumption rate of fishes collected …

Influence Of Perkinsus Marinus Infection And Oyster Health On Levels Of Human-Pathogenic Vibrios In Oysters, Lydia M. Bienlien

Dissertations, Theses, and Masters Projects

The eastern oyster Crassostrea virginica is an ecologically and commercially important species whose natural populations have been devastated by overharvesting, habitat destruction, and disease, but the rapid growth of oyster aquaculture has shown potential to restore the economic significance of this species. A key threat to the growth and sustainability of oyster aquaculture is the association of human-pathogenic Vibrio bacteria with product marketed for raw consumption. Two Vibrio species, Vibrio vulnificus and Vibrio parahaemolyticus, are the causes of the highest rates of seafood consumption-related mortality and gastrointestinal illness, respectively. Identification of the factors influencing V. vulnificus and V. parahaemolyticus prevalence …

Influence Of Structural Complexity And Location On The Habitat Value Of Restored Oyster Reefs, Melissa Ann Karp

Dissertations, Theses, and Masters Projects

In the Chesapeake Bay, < 1% of the historic oyster population remains, and efforts have been increasing to restore oysters and the services they provide. Building reefs that successfully provide ecosystem services–especially habitat and foraging grounds–may require different restoration techniques than those previously used, and success may depend on reef morphology (complexity), location, and environmental conditions. Salinity and habitat complexity are two important factors that may interact to effect benthic communities and predator-prey interactions on restored reefs. The goals of this project were: (1) Characterize the benthic communities on restored oyster reefs in lower Chesapeake Bay, and (2) examine the effects of structural complexity and salinity on benthic communities and predator-prey interactions. A two-year field survey of restored reefs was carried out in four rivers in lower Chesapeake Bay to characterize faunal communities on restored reefs and to quantify the effect of reef complexity on faunal communities. A laboratory mesocosm experiment was conducted to examine the effect of reef complexity on predator foraging. In total, 61 macrofaunal species were identified among all samples, and restored reefs supported on average, 6,169 org/m2 and 67.88 g-AFDW/m2. There were significant differences in the community composition and diversity among the rivers, and salinity was the environmental factor that best explained the observed differences in species composition across the rivers. Salinity and rugosity (i.e., structural complexity) both positively affected diversity, while salinity negatively affected macrofaunal abundance and biomass. Oyster density and rugosity positively affected macrofaunal biomass, and oyster density positively affected mud crab, polychaete, and mussel densities. In the mesocosm experiment, predator foraging, measured by proportion and number of prey consumed, was significantly reduced in the presence of oyster shell structure. However, predators were able to consume more prey when prey density was increased, even in the presence of oyster shell structure. These results combine to enhance our understanding of the benefits of increased habitat complexity for both prey and predators on restored oyster reefs. Increasing complexity worked to increase the abundance, biomass, and diversity of organisms inhabiting restored reefs, and even though predator consumption was reduced in the presence of structure compared to non-structured habitat, predators were able to consume more prey individuals when prey density was increased. Therefore, increasing the structure of oyster reef habitat may benefit prey species by providing refuge habitat, and benefit predators by providing an increased abundance of available prey items.

The Effects Of Drifting Fish Aggregating Devices On Bycatch In The Tropical Tuna Purse Seine Fisheries In The Atlantic And Indian Oceans, Julia Snouck-Hurgronje

Dissertations, Theses, and Masters Projects

Thousands of floating objects, known as drifting fish aggregating devices (dFADs), are released every year by commercial tropical tuna purse seine vessels in the three equatorial oceans to aggregate tuna and increase catch. The escalation in the number of dFADs deployed over the last three decades has caused changes in fishing effort that are poorly reflected in traditional indices of purse seine effort and catch per unit of effort (CPUE). In addition, concerns have been raised regarding the impacts of such high numbers of dFADs being deployed on both catch and bycatch species. I studied two aspects of dFAD deployments …

Unprecedented Restoration Of A Native Oyster Metapopulation, David M. Schulte

Dissertations, Theses, and Masters Projects

No abstract provided.

Deep-Pelagic (0-3000m) Fish Assemblage Structure Over The Mid-Atlantic Ridge In The Area Of The Charlie-Gibbs Fracture Zone, April B. Cook

Dissertations, Theses, and Masters Projects

Only a miniscule fraction of the world’s largest volume of living space, the ocean’s mid-water biome, has ever been sampled. As part of the International Census of Marine Life field project Mid-Atlantic Ridge Ecosystems (MAR-ECO), a discrete-depth trawling survey was conducted in 2009 aboard the NOAA ship Henry B. Bigelow to examine the pelagic faunal assemblage structure and distribution over the Charlie-Gibbs Fracture Zone (CGFZ) of the northern Mid-Atlantic Ridge. This is the first MAR-ECO project aimed specifically at describing diel vertical migration as a distributional phenomenon. Discrete-depth sampling from 0-3000 m was conducted during both day and night in …

Alternative Substrates As A Native Oyster (Crassostrea Virginica) Reef Restoration Strategy In Chesapeake Bay, Russell Paul Burke

Dissertations, Theses, and Masters Projects

Oyster shell for native oyster reef restoration is scarce in Chesapeake Bay and other estuaries (Chapter 1). Consequently, alternative substrates merit consideration in oyster restoration. This dissertation examines the suitability of shell alternatives, including granite, concrete, limestone marl, concrete modules and reefballs with reef surveys and experiments in the Rappahannock and Lynnhaven Rivers of Chesapeake Bay. Oyster recruitment, growth, survival, density, biomass, condition, and disease stress, as well as reef accretion and persistence, were measured. In the Lynnhaven River, intertidal riprap had a mean density of 978 oysters m-2 (165 g AFDM m-2) and peak densities > 2000 oysters m-2 (Chapter …

Characterization Of Exotic Pathogens Associated With The Suminoe Oyster, Crassostrea Ariakensis, Jessica A. Moss

Dissertations, Theses, and Masters Projects

The eastern oyster, Crassostrea virginica, once an integral part of the ecology and economy of Chesapeake Bay, has been severely depleted. Factors leading to the decline of the eastern oyster include over-harvesting, environmental degradation and disease pressure caused by the protozoans Haplosporidium nelsoni and Perkinsus marinus, known commonly as MSX and Dermo, respectively. Studies regarding the feasibility of introducing a nonnative oyster to the Bay were initiated, and field-based research on an Asian oyster, Crassostrea ariakensis, suggested that it might be a viable species for introduction. Research surrounding the proposed introduction has focused on recommendations such as those from the …

Trophic Ecology And Growth Dynamics Of Striped Bass (Morone Saxatilis) In Chesapeake Bay, With Reference To Mycobacteriosis, Kathleen Anne Mcnamee

Dissertations, Theses, and Masters Projects

No abstract provided.

Habitat Utilization And Salinity Tolerance Of The Sandbar Shark, Carcharhinus Plumbeus, In Virginia, Leonard Pace

Dissertations, Theses, and Masters Projects

No abstract provided.

Size-Selectivity Of The Commercial Sea Scallop (Placopecten Magellanicus) Dredge: Evaluation The Performance Of The New Bedford Style Dredge Configured With 4-Inch Rings And A 10-Inch Twine Top Using The Select Model, Noelle Yochum

Dissertations, Theses, and Masters Projects

A size-selectivity curve was constructed to characterize the performance of the New Bedford style Atlantic sea scallop (Placopecten magellanicus) dredge when it is configured to meet the requirements of Amendment #10 to the Sea Scallop Fishery Management Plan. The curve was generated using the SELECT model on catch-at-length data, obtained by simultaneously towing a New Bedford style dredge and a non-selective National Marine Fisheries Service sea scallop survey dredge from commercial scallop vessels. Data were collected during three cruises in the Northwest Atlantic between 2005 and 2006. One cruise was completed in Georges Bank (Groundfish Closed Area II) and two …

Migratory And Spawning Behavior Of American Shad In The James River, Virginia, Aaron W. Aunins

Dissertations, Theses, and Masters Projects

No abstract provided.

Diel And Site-Specific Feeding Of Young Striped Bass In A Heterogeneous Nursery Habitat, Sarah C. Muffelman

Dissertations, Theses, and Masters Projects

The Chesapeake Bay spawning stock of striped bass, Morone saxatilis, is considered one of the largest sources of juvenile production along the Atlantic coast and exhibits a high degree of interannual recruitment variability. Year class strength is judged by near-shore seine surveys that cover major tributaries of Chesapeake Bay and survey results are incorporated into annual stock assessments. In these surveys, the contribution of the Rappahannock River (Virginia) to total production is significant. In this system, abundance of juveniles is highest at a single seine site, suggesting that juvenile production may be related to habitat heterogeneity and food availability. To …

Developing A Stock Assessment For The Barndoor Skate (Dipturus Laevis) In The Northeast United States, Todd Gedamke

Dissertations, Theses, and Masters Projects

The barndoor skate Dipturus laevis is one of seven species in the United States Northwest Atlantic skate complex. The species received little attention until a recent article published in Science reported that the barndoor skate might be on the brink of extinction. In this study, we address not only the virtual lack of information on the life history of the species, but also develop methodologies to assist in the assessment of the barndoor skate population. to investigate the life history of the species, data were collected from 2,310 specimens caught during commercial sea scallop dredging in the southern section of …

Role Of Apolipoprotein A-1 In Defense Against Bacteria By Striped Bass (Morone Saxatilis), L. Danielle Johnston

Dissertations, Theses, and Masters Projects

No abstract provided.

Diet Of The Sandbar Shark, Carcharhinus Plumbeus, In Chesapeake Bay And Adjacent Waters, Julia K. Ellis

Dissertations, Theses, and Masters Projects

The sandbar shark, Carcharhinus plumbeus, is the most abundant large coastal shark in the temperate and tropical waters of the northwest Atlantic Ocean. The Chesapeake Bay, Virginia and adjacent waters serve as a nursery ground for C. plumbeus as well as many other fauna. Characterizing the diet of a higher trophic level predator such as the sandbar shark sheds light on a small portion of the temporally and spatially complex food web in the Bay. This study describes the diet of the sandbar shark, highlighting differences in diet within various portions of the nursery area, as well as ontogenetic changes …

Ecological Interactions Between Benthic Oyster Reef Fishes And Oysters, Juliana Maria Harding

Dissertations, Theses, and Masters Projects

Restoration of oyster reef structures rehabilitates habitats and the multi-level ecological communities built on eastern oysters (Crassostrea virginica), the keystone species. Quantitative descriptions of ecological interactions within a habitat are required to delineate essential fish habitats for management and protection. Parallel development of primary (oysters) and secondary trophic levels (benthic fishes) offer an ecological metric of restoration progress over time. The interaction between larval oysters and larval fishes (e.g., Gobiosoma bosc, Chasmodes bosquianus) is quantitatively examined. Oyster settlement estimates for Palace Bar reef, Piankatank River, Virginia are of the same order of magnitude as field densities of recently settled oysters. …

A Comparison Of Size Selectivity And Relative Efficiency Of Sea Scallop Trawls And Dredges, David B. Rudders

Dissertations, Theses, and Masters Projects

No abstract provided.