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Full-Text Articles in Physical Sciences and Mathematics

Impacts Of Lake Elevation Decline On Tui Chub, A Critical Forage Species For Lahontan Cutthroat Trout In Pyramid Lake, Nevada, Usa, Sarah Barnes May 2024

Impacts Of Lake Elevation Decline On Tui Chub, A Critical Forage Species For Lahontan Cutthroat Trout In Pyramid Lake, Nevada, Usa, Sarah Barnes

All Graduate Theses and Dissertations, Fall 2023 to Present

Lake level decline affects lakes worldwide, changing the availability and character of nearshore habitat used by fish to spawn, and increasing total dissolved solids (TDS), similar to salinity, a factor that negatively impacts fish health. Lake level decline can affect different lakes in different ways, but typically when lake level declines significantly, there is less nearshore habitat overall, and what nearshore habitat remains has less diverse habitat for fish. We investigated whether both impacts of lake level decline may be causing declines of Tui Chub Siphateles bicolor, a large minnow native to Pyramid Lake that spawns in nearshore habitat. …


State Of The Fisheries: Status Reports And Aquatic Resources Of Western Australia 2022/23, S.J. Newman, K.G. Santoro, D.J. Gaughan Dec 2023

State Of The Fisheries: Status Reports And Aquatic Resources Of Western Australia 2022/23, S.J. Newman, K.G. Santoro, D.J. Gaughan

Status reports of the fisheries and aquatic resources

Aquatic resources within Western Australia (WA) are in good condition, and this has positioned WA as a global leader in sustainable fisheries management. The sustainable fisheries of WA continue to support our strong economy and regional communities. Nonetheless, the lack of a consistent approach to build in the knowledge of Traditional Owners remains a gap in our longer term fisheries science in Western Australia.

Climate change and climate variability continues to impact fish stocks, challenging our ability to effectively monitor, assess, and manage fish stocks. We are continually working with our stakeholders, and the broader community to be adaptive, responsive, …


Nutritional Challenges Of Substituting Farmed Animals For Wild Fish In Human Diets, Sebastian A. Heilpern, Rafael M. Almeida, Kathryn J. Fiorella, Alexander S. Flecker, Demetra Williams, Peter B. Mcintyre Oct 2023

Nutritional Challenges Of Substituting Farmed Animals For Wild Fish In Human Diets, Sebastian A. Heilpern, Rafael M. Almeida, Kathryn J. Fiorella, Alexander S. Flecker, Demetra Williams, Peter B. Mcintyre

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Wild fisheries provide billions of people with a key source of multiple essential nutrients. As fisheries plateau or decline, nourishing more people will partially rely on shifting consumption to farmed animals. The environmental implications of transitions among animal-sourced foods have been scrutinized, but their nutritional substitutability remains unclear. We compared concentrations of six essential dietary nutrients across >5000 species of wild fishes, aquaculture, poultry and livestock species, representing >65% of animals consumed globally. Wild fishes are both more nutrient-dense and variable than farmed animals; achieving recommended intake of all nutrients with farmed species could require consuming almost four times more …


Collaborative And Engaged Research To Strengthen Equity And Adaptive Governance In Co-Managed Fisheries, Gabrielle V. Hillyer Aug 2023

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 …


State Of The Fisheries: Status Reports And Aquatic Resources Of Western Australia 2021/22, Department Of Primary Industries And Regional Development, Western Australia, S J. Newman, B S. Wise, K G. Santaro, D J. Gaughan Jul 2023

State Of The Fisheries: Status Reports And Aquatic Resources Of Western Australia 2021/22, Department Of Primary Industries And Regional Development, Western Australia, S J. Newman, B S. Wise, K G. Santaro, D J. Gaughan

Status reports of the fisheries and aquatic resources

Aquatic resources within Western Australia (WA) are in good condition, and this has positioned WA as a global leader in sustainable fisheries management. The sustainable fisheries of WA continue to support our strong economy and regional communities. Nonetheless, the lack of a consistent approach to build in the knowledge of Traditional Owners remains a gap in our longer-term fisheries science in Western Australia.

Climate change and climate variability continues to impact fish stocks, challenging our ability to effectively monitor, assess, and manage fish stocks. We are continually working with our stakeholders, and the broader community to be adaptive, responsive, and …


On The Architecture Of Collaboration In Inter-Organizational Natural Resource Management Networks, Gordon M. Hickey, Evelyn Roozee, Remko Voogd, Jasper R. De Vries, Antonia Sohns, Dongkyu Kim, Owen Temby Feb 2023

On The Architecture Of Collaboration In Inter-Organizational Natural Resource Management Networks, Gordon M. Hickey, Evelyn Roozee, Remko Voogd, Jasper R. De Vries, Antonia Sohns, Dongkyu Kim, Owen Temby

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

This paper reviews the architecture of collaboration that exists within inter-organizational natural resource management (NRM) networks. It presents an integrative conceptual framework designed to help operationalize the multi-level interactions that occur between different dimensions of trust, risk perception, and control as key concepts in inter-organizational collaboration. The objective is to identify and justify a series of propositions considered suitable for assessing inter-organizational NRM network collaboration through empirical work. Such an integrative conceptualization goes beyond the existing trust scholarship related to collaborative NRM, and, we argue, offers a useful starting point for further exploring some of the ‘inner’ social dynamics affecting …


Potential Repercussions Of Offshore Wind Energy Development In The Northeast United States For The Atlantic Surfclam Survey And Population Assessment, Sarah Borsetti, Daphne M. Munroe, Andrew M. Scheld, Eric N. Powell, John M. Klinck, Eileen E. Hofmann Jan 2023

Potential Repercussions Of Offshore Wind Energy Development In The Northeast United States For The Atlantic Surfclam Survey And Population Assessment, Sarah Borsetti, Daphne M. Munroe, Andrew M. Scheld, Eric N. Powell, John M. Klinck, Eileen E. Hofmann

CCPO Publications

The Atlantic surfclam Spisula solidissima fishery, which spans the U.S. Northeast continental shelf, is among the most exposed to offshore wind energy development impacts because of the overlap of fishing grounds with wind energy lease areas, the hydraulic dredges used by the fishing vessels, and the location of vessel home ports relative to the fishing grounds. The Atlantic surfclam federal assessment survey is conducted using a commercial fishing vessel in locations that overlap with the offshore wind energy development. Once wind energy turbines, cables, and scour protection are installed, survey operations within wind energy lease areas may be curtailed or …


Interactive Effects Of Climate Change-Induced Range Shifts And Wind Energy Development On Future Economic Conditions Of The Atlantic Surfclam Fishery, Stephanie Stromp, Andrew M. Scheld, John M. Klinck, Daphne M. Munroe, Eric N. Powell, Roger Mann, Sarah Borsetti, Eileen E. Hofmann Jan 2023

Interactive Effects Of Climate Change-Induced Range Shifts And Wind Energy Development On Future Economic Conditions Of The Atlantic Surfclam Fishery, Stephanie Stromp, Andrew M. Scheld, John M. Klinck, Daphne M. Munroe, Eric N. Powell, Roger Mann, Sarah Borsetti, Eileen E. Hofmann

CCPO Publications

Rising water temperatures along the northeastern U.S. continental shelf have resulted in an offshore range shift of the Atlantic surfclam Spisula solidissima to waters still occupied by ocean quahogs Arctica islandica. Fishers presently are prohibited from landing both Atlantic surfclams and ocean quahogs in the same catch, thus limiting fishing to locations where the target species can be sorted on deck. Wind energy development on and around the fishing grounds will further restrict the fishery. A spatially explicit model of the Atlantic surfclam fishery (Spatially Explicit Fishery Economics Simulator) has the ability to simulate the consequences of fishery displacement …


Fitting Time Series Models To Fisheries Data To Ascertain Age, Kathleen S. Kirch, Norou Diawara, Cynthia M. Jones Jan 2023

Fitting Time Series Models To Fisheries Data To Ascertain Age, Kathleen S. Kirch, Norou Diawara, Cynthia M. Jones

OES Faculty Publications

The ability of government agencies to assign accurate ages of fish is important to fisheries management. Accurate ageing allows for most reliable age-based models to be used to support sustainability and maximize economic benefit. Assigning age relies on validating putative annual marks by evaluating accretional material laid down in patterns in fish ear bones, typically by marginal increment analysis. These patterns often take the shape of a sawtooth wave with an abrupt drop in accretion yearly to form an annual band and are typically validated qualitatively. Researchers have shown key interest in modeling marginal increments to verify the marks do, …


Identifying New England’S Underutilized Seafood Species And Evaluating Their Market Potential In A Changing Climate, Amanda G. Davis, Michelle D. Staudinger, Katherine E. Mills Jan 2023

Identifying New England’S Underutilized Seafood Species And Evaluating Their Market Potential In A Changing Climate, Amanda G. Davis, Michelle D. Staudinger, Katherine E. Mills

Environmental Conservation Faculty Publication Series

Developing and diversifying market opportunities for lesser known yet abundant seafood species has been a successful strategy for seafood businesses in the Northeast United States. Since climate change and other stressors are currently threatening the economic vitality of New England’s seafood industry, it is important to identify if there are lesser-known species that could simultaneously support additional market opportunities and remain resilient in a warming climate. We developed a quantitative definition for the term “underutilized species’’ based on five criteria derived from science-based sustainable fishing metrics. Using this definition, we evaluated 47 stocks in the Northeast United States during the …


Demographic Groups Differ In Urban Recreational Behavior, Brandon Barlow Dec 2022

Demographic Groups Differ In Urban Recreational Behavior, Brandon Barlow

School of Natural Resources: Dissertations, Theses, and Student Research

Urban recreational behavior is an essential component to understanding both how our recreational opportunities will be utilized and how they can be further improved. By improving recreational opportunities, we can ensure safe and reliable emotional and physical outlets for users. As urban areas continue to expand both in geographic area and in population size, urban recreational opportunities will also see growth in the number of recreational users. Demographics provide the opportunity to further understand and predict recreational behavior, producing a variety of decision management tools. Our goal was to understand differences in urban recreational behavior among demographic groups. To address …


Climate Change Alters Aging Patterns Of Reservoir Aquatic Habitats, Leandro E. Miranda, Nicky M. Faucheux Sep 2022

Climate Change Alters Aging Patterns Of Reservoir Aquatic Habitats, Leandro E. Miranda, Nicky M. Faucheux

United States Geological Survey: Staff Publications

Two slow-moving developments are threatening reservoir aquatic habitats globally: aging and climate change. These events are projected to transform reservoir aquatic habitats in various and often unpredictable ways. Aging affects in-lake habitats directly, whereas climate change affects both in-lake and off-lake conditions. Climate change is expected to accelerate and, in some instances, possibly decelerate aging. Aging can be indexed as functional age, an index that signals the position of a reservoir along its lifespan relying on inlake descriptors of aquatic habitat. Using existing habitat datasets and climate projections, we developed semi-quantitative predictions about the effect of climate change on reservoir …


Valuing Angling On Reservoirs Using Benefit Transfer, Richard Melstrom, Mark A. Kaemingk, John C. Whitehead, Nicholas W. Cole, Christopher J. Chizinski, Kevin L. Pope Aug 2022

Valuing Angling On Reservoirs Using Benefit Transfer, Richard Melstrom, Mark A. Kaemingk, John C. Whitehead, Nicholas W. Cole, Christopher J. Chizinski, Kevin L. Pope

School of Environmental Sustainability: Faculty Publications and Other Works

Economic assessments are rarely applied to inland recreational fisheries for management purposes, especially when compared to fish, habitat, and creel assessments, yet economic assessments can provide critical information for management decisions. We provide a brief overview of economic value, key terminology, and existing economic techniques to address these issues. Benefit transfer, a technique used to measure economic value when an original analysis is not practicable, is conducted by drawing on existing estimates of economic value in similar contexts. We describe an application of benefit transfer to measure the economic value of several recreational fisheries in Nebraska, USA. We examine two …


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 May 2022

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 …


Comparing Molecular Methods To Estimate Fish Stomach Contents And Gastric Evacuation Rates: Implications For Measuring The Impacts Of Predation On Central Valley Chinook Salmon, Cory M. Dick Jan 2022

Comparing Molecular Methods To Estimate Fish Stomach Contents And Gastric Evacuation Rates: Implications For Measuring The Impacts Of Predation On Central Valley Chinook Salmon, Cory M. Dick

Cal Poly Humboldt theses and projects

Juvenile Chinook Salmon (Oncorhynchus tshawytscha) migrating through the Sacramento – San Joaquin Delta (the Delta) in central California have higher mortality rates than salmonids migrating through other west coast estuaries. Some hypotheses for high mortality rates include entrainment into water export facilities, physical alterations of the river system, and predation. Of these factors, predation is considered the least understood but may have the largest impact. Predation from large populations of non-native piscivorous fishes in the Delta is believed to effect abundances of Central Valley Chinook salmon, however sufficient data supporting this hypothesis is scarce. In this study, I …


Anthropogenic Impacts To Essential Habitats In The Gulf Of Maine: A Case Study Of The American Lobster, Homarus Americanus, And Its Fishery, Andrew Goode Dec 2021

Anthropogenic Impacts To Essential Habitats In The Gulf Of Maine: A Case Study Of The American Lobster, Homarus Americanus, And Its Fishery, Andrew Goode

Electronic Theses and Dissertations

The Gulf of Maine has been fundamentally altered by anthropogenic forcings for decades and offers an ideal study system to monitor response to change. Through complex interactions between ocean warming, altered demographic bottlenecks, and reduced top-down controls, the American lobster (Homarus americanus Milne Edwards) capitalized on favorable conditions and proliferated within the Gulf of Maine. These changes catalyzed the expansion of the lobster fishery, elevated its status as North America’s most valuable marine resource, and shifted coastal communities towards a virtual lobster monoculture. The same processes that facilitated lobster to capitalize on favorable conditions may come with unintended consequences …


Studies In Consumption And Production Of South Carolina Aquaculture Products, David Cheplick Dec 2021

Studies In Consumption And Production Of South Carolina Aquaculture Products, David Cheplick

All Theses

Market demand for seafood products among South Carolina (SC) consumers has led to increased aquaculture production as a means of supporting the seafood supply chain across the state. Our objective is broken into four distinct parts; (1) understanding consumer’s preferences and perceptions of seafood, (2) calculating their willingness to pay (WTP) for seafood products available in SC using attributes of sustainability and locality; and (3) gathering production metric and anecdotal data from SC oyster growers. Previous research assessing the market channels of seafood in South Carolina is compared to survey results. Respondents indicated that taste and quality were the most …


2021 Assessment Of The Status Of The West Coast Demersal Scalefish Resource, David V. Fairclough, Sybrand Alex Hesp, Ainslie Denham, Emily A. Fisher, Rachel Marks, Karina L. Ryan, Elaine Lek, Rhys Allen, Brett M. Crisafulli Oct 2021

2021 Assessment Of The Status Of The West Coast Demersal Scalefish Resource, David V. Fairclough, Sybrand Alex Hesp, Ainslie Denham, Emily A. Fisher, Rachel Marks, Karina L. Ryan, Elaine Lek, Rhys Allen, Brett M. Crisafulli

Fisheries research reports

A recovery program for the West Coast Demersal Scalefish Resource was introduced between late 2007 and early 2010, based on the maintenance of retained catches of demersal species (overall suite and each indicator species) by both the commercial and recreational sectors below 50% of the catches reported in 2005/06 (original catch recovery benchmarks).

Catch reductions were aimed at reducing exploitation levels (F, long-term fishing mortality of the key indicator species’ stocks) to below the threshold reference point (F = M, the natural mortality rate), which would then allow stocks to recover to above the …


Reproductive Characteristics Of Red Snapper Lutjanus Campechanus On Artificial Reefs In Different Jurisdictions, Catheline Y. M. Froehlich, Adam M. Lee, Ramiro Oquita, Carlos E. Cintra-Buenrostro, J. Dale Shively Sep 2021

Reproductive Characteristics Of Red Snapper Lutjanus Campechanus On Artificial Reefs In Different Jurisdictions, Catheline Y. M. Froehlich, Adam M. Lee, Ramiro Oquita, Carlos E. Cintra-Buenrostro, J. Dale Shively

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Reproductive activity of Red Snapper Lutjanus campechanus (Poey, 1860) at artificial reefs (ARs) are only recently being investigated. Yet, the management of the fishery differs on a regional basis with state and federal jurisdictions, and reproductive differences among regions have not been investigated. To compare the reproductive activity of L. campechanus among state (inshore) and federal (offshore) jurisdictions, individuals were collected in the northwestern Gulf of Mexico from four ARs on a quarterly basis for 2 yrs. Inshore sites exhibited fishing pressure year round whereas offshore sites only had fishing season open during a few months of summer. Collected individuals …


Vignette 09: Derelict Fishing Gear, Jason Morgan May 2021

Vignette 09: Derelict Fishing Gear, Jason Morgan

Institute Publications

Derelict fishing gear—nets, pots, and other gear lost during fishing operations or vessel transit—has been implicated in several aspects of degradation in the Salish Sea. Derelict gear can degrade marine habitats by scouring or preventing habitat access through accumulation of gear or by fundamentally altering habitats by trapping fine sediments and changing the substrate. Derelict gear has also been implicated in the deaths of countless fish, marine mammals, seabirds, and invertebrates in the Salish Sea. The issue of derelict fishing gear affects all reaches of the Salish Sea, albeit on different scales, and the Northwest Straits Initiative has provided its …


Global Connectivity Of Southern Ocean Ecosystems, Eugene J. Murphy, Nadine M. Johnston, Eileen E. Hofmann, Richard A. Phillips, Jennifer A. Jackson, Andrew J. Constable, Sian F. Henley, Jessica Melbourne-Thomas, Rowan Trebilco, Rachel D. Cavanagh, Geraint A. Tarling, Ryan A. Saunders, David K.A. Barnes, Daniel P. Costa, Stuart P. Corney, Ceridwen I. Fraser, Juan Höfer, Kevin A. Hughes, Chester J. Sands, Sally E. Thorpe, Philip N. Trathan, José C. Xavier Jan 2021

Global Connectivity Of Southern Ocean Ecosystems, Eugene J. Murphy, Nadine M. Johnston, Eileen E. Hofmann, Richard A. Phillips, Jennifer A. Jackson, Andrew J. Constable, Sian F. Henley, Jessica Melbourne-Thomas, Rowan Trebilco, Rachel D. Cavanagh, Geraint A. Tarling, Ryan A. Saunders, David K.A. Barnes, Daniel P. Costa, Stuart P. Corney, Ceridwen I. Fraser, Juan Höfer, Kevin A. Hughes, Chester J. Sands, Sally E. Thorpe, Philip N. Trathan, José C. Xavier

CCPO Publications

Southern Ocean ecosystems are globally important. Processes in the Antarctic atmosphere, cryosphere, and the Southern Ocean directly influence global atmospheric and oceanic systems. Southern Ocean biogeochemistry has also been shown to have global importance. In contrast, ocean ecological processes are often seen as largely separate from the rest of the global system. In this paper, we consider the degree of ecological connectivity at different trophic levels, linking Southern Ocean ecosystems with the global ocean, and their importance not only for the regional ecosystem but also the wider Earth system. We also consider the human system connections, including the role of …


Status Reports Of The Fisheries And Aquatic Resources Of Western Australia 2020/21, S.J. Newman, B.S. Wise, K.G. Santoro, D.J. Gaughan Jan 2021

Status Reports Of The Fisheries And Aquatic Resources Of Western Australia 2020/21, S.J. Newman, B.S. Wise, K.G. Santoro, D.J. Gaughan

Status reports of the fisheries and aquatic resources

The Status Reports of the Fisheries and Aquatic Resources of Western Australia (SRFAR) provide an annual update on the state of the fish stocks and other aquatic resources of Western Australia (WA). These reports outline the most recent assessments of the cumulative risk status for each of the aquatic resources (assets) within WA’s six Bioregions using an Ecosystem Based Fisheries Management (EBFM) approach. The Departments’ risk based EBFM framework is the State government’s basis for management of all Western Australia’s aquatic resources.


First Record Of Blacknape Large-Eye Bream Gymnocranius Satoi (Perciformes: Lethrinidae) In The Philippines, Nicko Amor Flores, Jade Tifany Rey, Jeffrey T. Williams, Kent Carpenter, Mudjekeewis Santos Jan 2021

First Record Of Blacknape Large-Eye Bream Gymnocranius Satoi (Perciformes: Lethrinidae) In The Philippines, Nicko Amor Flores, Jade Tifany Rey, Jeffrey T. Williams, Kent Carpenter, Mudjekeewis Santos

Biological Sciences Faculty Publications

The Philippines has been regarded as the center of the center of marine shorefish biodiversity, having the highest number of fish species per square area in the world. The blacknape large-eye bream, Gymnocranius satoi, has been reported to occur from Southern Japan, Taiwan to Northwestern Australia and to the Coral Sea, but has not previously been recorded from the Philippines. From 2011 – 2019, the National Fisheries Research and Development Institute (NFRDI) collaborated with the National Museum of Natural History of the Smithsonian Institution (NMNH/SI), USA, and the Old Dominion University (ODU), Virgina, USA, to inventory all commercial fish …


Otolith Age Validation And Microchemical Investigation Of The Northern Stock F Atlantic Black Sea Bass (Centropristis Striata), Elise R. Koob Dec 2020

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 …


Nutrition Management In Fodder Grass Production For Fisheries In Hubei, F. Chen, J. W. Lu, X. K. Li, W. X. Li, H. X. Zhao, J. M. Lu Aug 2020

Nutrition Management In Fodder Grass Production For Fisheries In Hubei, F. Chen, J. W. Lu, X. K. Li, W. X. Li, H. X. Zhao, J. M. Lu

IGC Proceedings (2001-2023)

No abstract provided.


Abalone Recruitment In Abalone Recruitment In Low-Density And Aggregated Populations Facing Climatic Stress, Ryan K. Walter Aug 2020

Abalone Recruitment In Abalone Recruitment In Low-Density And Aggregated Populations Facing Climatic Stress, Ryan K. Walter

Physics

Understanding spatial and temporal patterns in the recruitment of marine invertebrates with complex life histories remains a critical knowledge gap in marine ecology and fisheries. As marine invertebrates are facing multiple stressors from overfishing and climatic stress, it is important to evaluate the conditions that facilitate recruitment in low-density populations. The red abalone Haliolis rufescens historically supported an economically important fishery in California, but the fishery was sequentially closed as stocks declined, and the last fished area was closed in 2018 following the collapse of the kelp forests in Northern California. Here, red abalone recruitment was evaluated annually from 2012 …


Microplastics In Mississippi River Fishes: A Watershed Approach, Ahmed Gad Jun 2020

Microplastics In Mississippi River Fishes: A Watershed Approach, Ahmed Gad

LSU Master's Theses

Microplastics are plastic particles less than 5mm that come from different sources, such as industrial products, cosmetics, and the breakdown of the macroplastics. Microplastics derive from terrestrial sources but concentrate in flowing freshwaters where they may enter aquatic food webs. The northern Gulf of Mexico has shown very high microplastic concentrations, which are assumed to be sourced from the Mississippi River and its watershed. This study seeks to study microplastics in fish in the Mississippi River and the Gulf of Mexico. Fish stomachs and intestines from fish underwent chemical digestion, filtration, and microplastics identification and enumeration through FT-IR spectrometry. Chapter …


Quantifying Extinction Risk In Commercial Marine Species, Rondi Nordal May 2020

Quantifying Extinction Risk In Commercial Marine Species, Rondi Nordal

Scholars Week

The sustainability of some species is at risk as a result of anthropogenic influences such as climate change and harvest. This study focused on the combined role of economic and ecological factors that can lead to overharvesting of commercial marine species and aimed to understand the relationship between ecological extinction risk, biological productivity, and economic value. We used existing economic, ecological, and extinction risk data and compiled it for use in the analysis. We focused on maximum sustainable yield as an indicator of productivity, economic data that indicated the landed value of a species, and International Union for the Conservation …


Examining The Northern Shrimp Fishery In A Changing Gulf Of Maine, Ashley N. Charleson May 2020

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 …


An Analysis Of Dredge Efficiency For Surfclam And Ocean Quahog Commercial Dredges, Leanne Poussard May 2020

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 …