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Fisheries management

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Full-Text Articles in Aquaculture and Fisheries

Enhancing Walleye (Ogaa) Recruitment: Evaluating Assisted Reproduction As A Mitigation Strategy, Douglass Keiser May 2026

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 …


Largemouth Bass Diet Changes Through The Summer In Central Minnesota, Ethan Kunz Jan 2026

Largemouth Bass Diet Changes Through The Summer In Central Minnesota, Ethan Kunz

Journal of Earth and Life Science

Largemouth Bass Micropterus nigricans is one of the most widespread fish species in the world, due in part to human introduction for angling. Largemouth Bass are opportunistic predators that will consume the largest prey they can often find; however, it has been shown that their diet mainly consists of invertebrates such as crayfish, with less focus on other fish species. This research aimed to determine what the Largemouth Bass diets in Central Minnesota consist of, and how they may change from the beginning of summer through the beginning of fall. A total of 174 Largemouth Bass were sampled from late …


Characterization Of A Coastwide Sheepshead (Archosargus Probatocephalus) Fishery Reveals Increased Fishing Pressure During Spawning Activity In Texas, Ethan T. Getz, Catherine M. Eckert, Charles Downey Iii Jan 2026

Characterization Of A Coastwide Sheepshead (Archosargus Probatocephalus) Fishery Reveals Increased Fishing Pressure During Spawning Activity In Texas, Ethan T. Getz, Catherine M. Eckert, Charles Downey Iii

Gulf and Caribbean Research

Sheepshead (Archosargus probatocephalus) have been characterized as one of the most vulnerable species to overfishing in the Gulf of Mexico (GOM) based on their reproductive strategy of spawning in aggregations. Here, we analyzed fishery—independent and dependent data (1983—2023) collected by the Texas Parks and Wildlife Department to assess Sheepshead populations and describe the fishery in Texas. Gill net sampling was used to describe Sheepshead abundance and distribution, while creel survey data and commercial landings were used to determine spatial and temporal characteristics of the fishery and evaluate targeted fishing activity during the spawning season. Sheepshead encountered in gill …


Statewide Northern Pike Response To Minnesota’S 2018 Regulation Change, Elijah Wozniak Jan 2026

Statewide Northern Pike Response To Minnesota’S 2018 Regulation Change, Elijah Wozniak

Journal of Earth and Life Science

Management of northern pike (Esox lucius) is challenging because it attempts to balance ecological sustainability with angler interests. Northern pike often stunt their own growth by diminishing the size and abundance of prey fish, their food source. Anglers are often displeased when small pike occur in high population densities. In response to populations of small northern pike, the DNR implemented a new, statewide northern pike regulation in 2018. The objective of this study was to determine whether the regulation successfully changed the mean weight, length, and CPUE of northern pike in Minnesota. The secondary objective was to test …


Comparison Of Calcified Structures To Estimate Ages Of Northern Pike Esox Lucius In Various Lakes, Kaed Rauk Jan 2026

Comparison Of Calcified Structures To Estimate Ages Of Northern Pike Esox Lucius In Various Lakes, Kaed Rauk

Journal of Earth and Life Science

Northern pike Esox lucius are a dominant predatory fish in many aquatic systems. They can have significant impacts on the ecosystems they inhabit and are also a popular game fish among anglers. However, northern pike are a difficult species to age accurately. This study aimed to compare calcified aging structures to identify trends and determine which structure provides the most accurate age estimates. A total of 119 northern pike were sampled, and multiple structures from each fish were independently aged by two readers. The coefficient of variation (CV) was calculated for each structure to assess precision. Sectioned sagittal otoliths exhibited …


Size Structure Comparison Of Bluegill In Lakes With And Without Special Regulations, Jenna Lawin Jan 2026

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 …


Population Genomics Of Pacific Herring Spawning Aggregations In The Eastern Bering Sea, Sydney A. Almgren Dec 2025

Population Genomics Of Pacific Herring Spawning Aggregations In The Eastern Bering Sea, Sydney A. Almgren

Fisheries

Pacific herring (Clupea pallasii) is a critical forage fish to the marine environment, economy, and culture of Alaska. However, despite the importance of Pacific herring in Alaska and throughout the North Pacific, knowledge gaps exist for foundational genomic characteristics of the species, including genetic population structure and the basis of genetic sex determination. In this thesis, I addressed these knowledge gaps using low coverage, whole genome sequencing. I assessed population structure and genetic diversity across seven sampling sites and found three genetic populations: Unalaska, the farthest south sampling location, Kotzebue, the farthest north, and a third group unassociated with geographic …


Fisheries Research Report No. 350: Recreational Vessel Retrievals In Western Australia - 2009 To 2024, Stephen C. Bradshaw, Claire B. Smallwood, Stuart J. Blight, Troy Matthews, Karina L. Ryan Aug 2025

Fisheries Research Report No. 350: Recreational Vessel Retrievals In Western Australia - 2009 To 2024, Stephen C. Bradshaw, Claire B. Smallwood, Stuart J. Blight, Troy Matthews, Karina L. Ryan

Fisheries Research Reports

This report provides a time series (2009 – 2024) of the total number of recreational vessel (powerboat) retrievals at a spatial (boat ramp) and temporal (annual, month, hour) resolution for 32 boat ramps distributed from Wyndham to Esperance. This time series has been developed using a workflow that outlines each step, from acquiring raw video data to producing a completed time series of vessel retrievals. As part of this workflow, modelling was undertaken to impute counts of vessel retrieval for sites and hours for which data had not been read, or for which there were significant outages. Features within the …


Common Terns (Sterna Hirundo) As Bioindicators For Atlantic Herring (Clupea Harengus) Distribution In The Gulf Of Maine, Logan R. Becker Apr 2025

Common Terns (Sterna Hirundo) As Bioindicators For Atlantic Herring (Clupea Harengus) Distribution In The Gulf Of Maine, Logan R. Becker

Student Publications

Effective fisheries management is increasingly challenged by climate-driven shifts in species distribution and by a lack of data on early life stages of key forage fish species. In the Gulf of Maine, Atlantic herring (Clupea harengus), a once economically dominant fishery species and a key prey species for many dependent predators, has declined due to poor early-stage recruitment and warming waters. Despite this decline, current trawl surveys do not inform early-stage Atlantic herring distribution due to mesh size limitations, leaving critical gaps in our knowledge. To address this knowledge gap, I used common terns (Sterna hirundo) …


Size Structure Of Black Crappie And Bluegill In Northern, Eastern, Western, And Southern Minnesota, Ray Anderson Jan 2025

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 …


Estimation Of Effective Number Of Breeders And Effective Population Size In An Abundant And Heavily Exploited Marine Teleost, Andrea Bertram, Justin Bell, Chris Brauer, David Fairclough, Paul Hamer, Jonathan Sandoval-Castillo, Maren Wellenreuther, Luciano B. Beheregaray Jul 2024

Estimation Of Effective Number Of Breeders And Effective Population Size In An Abundant And Heavily Exploited Marine Teleost, Andrea Bertram, Justin Bell, Chris Brauer, David Fairclough, Paul Hamer, Jonathan Sandoval-Castillo, Maren Wellenreuther, Luciano B. Beheregaray

Fisheries Research Articles

Obtaining reliable estimates of the effective number of breeders (Nb) and generational effective population size (Ne) for fishery-important species is challenging because they are often iteroparous and highly abundant, which can lead to bias and imprecision. However, recent advances in understanding of these parameters, as well as the development of bias correction methods, have improved the capacity to generate reliable estimates. We utilized samples of both single-cohort young of the year and mixed-age adults from two geographically and genetically isolated stocks of the Australasian snapper (Chrysophrys auratus) to investigate the feasibility of generating reliable Nb and Ne estimates for a …


Population Demography, Occupancy, And Connectivity Of Invasive Bigheaded Carp In The Platte River, Nebraska And Its Tributaries, Blake W. Logan Jul 2024

Population Demography, Occupancy, And Connectivity Of Invasive Bigheaded Carp In The Platte River, Nebraska And Its Tributaries, Blake W. Logan

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

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis, collectively referred to as bigheaded carp, are invasive species in the United States of America that have expanded their range throughout the Missouri River basin in the last three decades. It may be desirable to develop management plans directed at the monitoring, control, or removal of bigheaded carp within the Missouri River basin. However, a knowledge gap exists regarding bigheaded carp ecology in Missouri River tributaries, which may be important for the development of management plans. As such, this study characterized bigheaded carp population demographics, occupancy, and connectivity in …


Specific Measurements Of A Yellow Perch Head Compared To The Total Length, Alex Timm Jan 2024

Specific Measurements Of A Yellow Perch Head Compared To The Total Length, Alex Timm

Journal of Earth and Life Science

Yellow Perch Perca flavescens is a popular fish for harvesting in Minnesota. Because of this the Minnesota Department of Natural Resources survey populations with gill nets, however, some water bodies have Rusty Crayfish Faxonius rusticus that commonly consume most of the body leaving only the head to be accurately measured. The goal of this research was to see if there is a relationship between specific measurements of the head and the total length of the fish. The number of Yellow Perch sampled in this study was 72 and all came from Lake Bemidji in Minnesota during the month of October …


Waterbody Size Predicts Bank- And Boat-Angler Efforts, Derek S. Kane, Kevin L. Pope, Keith D. Koupal, Mark A. Pegg, Christopher J. Chizinski, Mark A. Kaemingk Jul 2023

Waterbody Size Predicts Bank- And Boat-Angler Efforts, Derek S. Kane, Kevin L. Pope, Keith D. Koupal, Mark A. Pegg, Christopher J. Chizinski, Mark A. Kaemingk

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Bank- and boat-angler efforts are logistically difficult and costly to estimate, preventing landscape-scale estimates that are required to address current and future challenges (e.g., climate change, invasive species) for inland recreational fisheries. Using a large Nebraska, USA, recreational fishery dataset (N = 67 waterbodies), we demonstrate that waterbody size can be used to predict bank- and boat-angler efforts across a heterogeneous landscape of extra small (< 104 ha) and large (> 647 ha) waterbodies. Bank and boat anglers respond to waterbody size, however these relationships appear to be unique between the two angler types. Boat-angler efforts increased as a function of waterbody size, whereas bank-angler …


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 …


Fisheries Genomics Of Snapper (Chrysophrys Auratus) Along The West Australian Coast, Andrea Bertram, David Fairclough, Jonathan Sandoval-Castillo, Chris Brauer, Anthony Fowler, Maren Wellenreuther, Luciano B. Beheregaray Jun 2022

Fisheries Genomics Of Snapper (Chrysophrys Auratus) Along The West Australian Coast, Andrea Bertram, David Fairclough, Jonathan Sandoval-Castillo, Chris Brauer, Anthony Fowler, Maren Wellenreuther, Luciano B. Beheregaray

Fisheries Research Articles

The efficacy of fisheries management strategies depends on stock assessment and management actions being carried out at appropriate spatial scales. This requires understanding of spatial and temporal population structure and connectivity, which is challenging in weakly structured and highly connected marine populations. We carried out a population genomics study of the heavily exploited snapper (Chrysophrys auratus) along ~2600 km of the Australian coastline, with a focus on Western Australia (WA). We used 10,903 filtered SNPs in 341 individuals from eight sampling locations to characterize population structure and connectivity in snapper across WA and to assess if current spatial …


Comparison Of Bigheaded Carp Reproduction In Tributaries Of The Illinois And Wabash Rivers, David J. Yff Jan 2022

Comparison Of Bigheaded Carp Reproduction In Tributaries Of The Illinois And Wabash Rivers, David J. Yff

Masters Theses

Understanding environmental conditions that support bigheaded carp (Hypophthalmichthys sp.) reproduction in tributary rivers provides key predictions of their invasion throughout the United States. Past research, primarily in larger order rivers, identified factors such as discharge, temperature, and turbidity as main environmental drivers of bigheaded carp reproduction. I used the variable hydrologic conditions between the Illinois and Wabash Rivers to compare environmental conditions between tributaries of each basin, determine which conditions influence bigheaded carp reproduction in tributaries, and predict tributaries likely to support bigheaded carp reproduction. Three tributaries of the Illinois and Wabash Rivers were sampled for ichthyoplankton from …


Population Characteristics Of Three Black Bass Species In The Upper Ohio River Drainage, Levi Foster Brown Jan 2022

Population Characteristics Of Three Black Bass Species In The Upper Ohio River Drainage, Levi Foster Brown

Graduate Theses, Dissertations, and Problem Reports (ETD)

In West Virginia, species of black bass are economically and ecologically important and support popular fisheries. In the state’s large, navigable river systems, recent information suggests that anglers consider these fisheries diminished relative to their historic stocks. This study sought to describe the population characteristics of Largemouth, Smallmouth, and Spotted Bass in the upper Ohio River drainage and evaluate possible management actions. Low relative abundances coupled with poor growth estimates for Largemouth and Spotted Bass suggests that a suite of environmental and anthropogenic factors may be reducing the quality of their recreational fisheries. Conversely, demographic estimates produced for Smallmouth Bass …


Overfishing Drives Over One-Third Of All Sharks And Rays Toward A Global Extinction Crisis, Nicholas K. Dulvy, Nathan Pacoureau, Cassandra L. Rigby, Riley A. Pollom, Rima W. Jabado, David A. Ebert, Brittany Finucci, Caroline M. Pollock, Jessica Cheok, Danielle H. Derrick, Katelyn B. Herman, C. Samantha Sherman, Wade J. Vanderwright, Julia M. Lawson, Rachel H.L. Walls, John K. Carlson, Patricia Charvet, Kinattumkara K. Bineesh, Daniel Fernando, Gina M. Ralph, Jay H. Matsushiba, Craig Hilton-Taylor, Sonja V. Fordham, Colin A. Simpfendorfer Nov 2021

Overfishing Drives Over One-Third Of All Sharks And Rays Toward A Global Extinction Crisis, Nicholas K. Dulvy, Nathan Pacoureau, Cassandra L. Rigby, Riley A. Pollom, Rima W. Jabado, David A. Ebert, Brittany Finucci, Caroline M. Pollock, Jessica Cheok, Danielle H. Derrick, Katelyn B. Herman, C. Samantha Sherman, Wade J. Vanderwright, Julia M. Lawson, Rachel H.L. Walls, John K. Carlson, Patricia Charvet, Kinattumkara K. Bineesh, Daniel Fernando, Gina M. Ralph, Jay H. Matsushiba, Craig Hilton-Taylor, Sonja V. Fordham, Colin A. Simpfendorfer

Biological Sciences Faculty Publications

The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes-sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species were threatened. Now, 391 (32.6%) species are threatened with extinction. When this percentage of threat is applied to Data Deficient species, more than one-third (37.5%) of chondrichthyans are estimated to be threatened, with much of this change resulting from new information. Three species are Critically Endangered (Possibly Extinct), representing …


Integrated Analyses Of Snp-Genotype And Environmental Data In A Continuously Distributed Snapper Species (Lutjanus Johnii, Bloch, 1792) Reveals A Mosaic Of Populations And A Challenge For Sustainable Management, Laura Taillebois, Danielle Davenport, Diane P. Barton, David Alexander Cook, Thor Saunders, Mark Hearnden, Richard J. Saunders, Stephen J. Newman, Michael J. Travers Oct 2021

Integrated Analyses Of Snp-Genotype And Environmental Data In A Continuously Distributed Snapper Species (Lutjanus Johnii, Bloch, 1792) Reveals A Mosaic Of Populations And A Challenge For Sustainable Management, Laura Taillebois, Danielle Davenport, Diane P. Barton, David Alexander Cook, Thor Saunders, Mark Hearnden, Richard J. Saunders, Stephen J. Newman, Michael J. Travers

Fisheries Research Articles

Understanding population structure is important for predicting the outcomes of anthropogenic development, harvest, and environmental change on the abundance of fisheries species. Logically, the use of several data sources is best for delineating population structure, but combining across data types adds extra challenges as results can be incongruent. Here, genetic and environmental markers were used to test hypotheses about population structure in a collection of 523 tropical inshore finfish (Lutjanus johnii) across northern Australia from 20 locations. Redundancy analyses (RDA) were used to statistically test for correlations among data sources providing a basis for reconciliation and insights into ecological and …


Continental-Scale Network Reveals Cross-Jurisdictional Movements Of Sympatric Sharks With Implications For Assessment And Management, Charlie Huveneers, Yuri Niella, Michael Drew, Rory Mcauley, Paul A. Butcher, Victor Peddemors, Daniela Waltrick, Chris Dowling, Silas Mountford, Ian S. Keay, Matias Braccini Aug 2021

Continental-Scale Network Reveals Cross-Jurisdictional Movements Of Sympatric Sharks With Implications For Assessment And Management, Charlie Huveneers, Yuri Niella, Michael Drew, Rory Mcauley, Paul A. Butcher, Victor Peddemors, Daniela Waltrick, Chris Dowling, Silas Mountford, Ian S. Keay, Matias Braccini

Fisheries Research Articles

Understanding the movement ecology of marine species and connectivity of populations is required for effective fisheries management. This is especially the case for species with wide-ranging distributions for which movement can span across several jurisdictions with different management regulations. We used the Australian national network of acoustic receivers facilitated by the Integrated Marine Observing System (IMOS) to describe the extent and frequency of movements for two large epipelagic shark species, the bronze whaler (Carcharhinus brachyurus) and dusky shark (Carcharhinus obscurus). A total of 210 sharks (117 bronze whalers and 93 dusky sharks) were tracked for a …


Evaluation Of Population Structure, Age, Growth, And Mortality Of Blue Catfish And Flathead Catfish Within The Robert C. Byrd Pool Of The Ohio And Kanawha Rivers, Joseph Vincent Siegel Jan 2021

Evaluation Of Population Structure, Age, Growth, And Mortality Of Blue Catfish And Flathead Catfish Within The Robert C. Byrd Pool Of The Ohio And Kanawha Rivers, Joseph Vincent Siegel

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Ohio River is continuing to recover from a long history of anthropogenic impacts. Blue Catfish were considered locally extirpated from the West Virginia sections and have been reintroduced through fingerling stockings beginning in 2002. Flathead Catfish are naturally sustaining in the pool and combined with Blue Catfish provide two popular recreational fisheries. The Blue Catfish and Flathead Catfish studies shared similar objectives: (1) evaluating size structure, (2) estimating growth rates, and (3) estimating annual mortality. From 2017 to 2020, we collected catfish annually through low frequency electrofishing and trotline surveys at 10 fixed locations. Electrofishing catch rates for Blue …


Utah Land Management Evaluation And Assessment Network Needs Assessment, Jordan Smith Jun 2020

Utah Land Management Evaluation And Assessment Network Needs Assessment, Jordan Smith

All Current Publications

It can be difficult to make and implement land management decisions that are informed by the best available science, satisfy different stakeholders, and are compliant with established policies and regulations. Local, state, and federal entities with the capacity to influence land management decisions, can benefit from an understanding of the shared needs of landowners and managers. This needs assessment reports on the shared information, funding, and research needs expressed by land managers and owners throughout Utah who make decisions about: (1) fire prevention and suppression; (2) livestock grazing; (3) fisheries; or (4) wildlife. The report provides a high-level assessment of …


Cpue Standardization For The Pacific Saury (Cololabis Saira) Fishery In The Northwest Pacific, Wen-Bin Huang, Chih-Hao Hsieh, Tai-Sheng Chiu, Wei-Ting Hsu, Chih-Shin Chen Oct 2019

Cpue Standardization For The Pacific Saury (Cololabis Saira) Fishery In The Northwest Pacific, Wen-Bin Huang, Chih-Hao Hsieh, Tai-Sheng Chiu, Wei-Ting Hsu, Chih-Shin Chen

Journal of Marine Science and Technology–Taiwan

In stock assessment and fisheries management, the standardization of catch per unit effort (CPUE) is critical to derive an effective index of the abundance of exploited fish stocks. In addition to developing various statistical models, a method including the relative fishing power (RFP) of individual vessels has been developed from an intuition concept and applied to bottom trawl fisheries using logbookbased data. This is a convenient and traightforward approach for standardizing the catch-effort data of a fishery. The Pacific saury is a pelagic fish species, and its stock in the Northwest Pacific has been targeted by international fleets since the …


Management Strategy Evaluation: Transdisciplinary And Transparent Natural Resource Management, Eileen Hofmann, Lisa Maddison, Ingrid Van Putten Jan 2019

Management Strategy Evaluation: Transdisciplinary And Transparent Natural Resource Management, Eileen Hofmann, Lisa Maddison, Ingrid Van Putten

CCPO Publications

Management Strategy Evaluation (MSE) is a modelling tool used to evaluate sufficiently realistic simulations of potential policy choices in complex systems. As a contribution to the Integrated Marine Biosphere Research (IMBeR) project IMBIZO V, which occurred in October 2017, a workshop was convened with the goal of developing a coherent understanding of best-practice approaches for MSEs. MSEs are becoming standard approaches to characterizing risk across fisheries management organizations globally. MSEs are important tools that aid in delineating objectives, costs, and constraints that define risk and provide a possible mechanism to meet assessment challenges. The MSE workshop considered case studies drawn …


Changes In Walleye Fecundity And Egg Size Before, During, And After Rehabilitation Of The Red Lakes Fishery, Benjamin J. Miller, Benjamin D. Erb Jan 2019

Changes In Walleye Fecundity And Egg Size Before, During, And After Rehabilitation Of The Red Lakes Fishery, Benjamin J. Miller, Benjamin D. Erb

Journal of Earth and Life Science

The Red Lakes in northern Minnesota experienced a major Walleye Sander vitreus fishery crash in the late 20th century, but has since recovered to record abundances and supports a major commercial and recreational fishery. Fecundity is an integral aspect of recruitment that can contribute greatly to the understanding of fishery population dynamics. To elucidate the effects of varying Walleye densities and exploitation rates on fecundity and egg size in years 1989 (overexploited fishery), 2004 (recovering fishery), and 2017 (recovered fishery), we analyzed linear models that related fecundity or egg size to morphological features for these three sampling periods. Walleyes were …


Analysis Of Unconventional Oil And Gas Impacts On Downstream Fish Assemblages And Physiological Stress, Joshua Noah Ankeny Jan 2019

Analysis Of Unconventional Oil And Gas Impacts On Downstream Fish Assemblages And Physiological Stress, Joshua Noah Ankeny

Graduate Theses, Dissertations, and Problem Reports (ETD)

Unconventional Oil and Gas (UOG) production has been steadily expanding throughout the mid-Atlantic since 2008. Increased sedimentation, degraded water chemistry and an overall decrease in habitat quality due to UOG is anticipated to negatively impact aquatic inhabitants, a common observation in other stressed landscapes (i.e., mining, agriculture, development). We assessed stream health through both community analysis and physiological parameters (i.e., growth and hematocrit). A before-after-control-impact study uncovered three fish metrics that were significantly different following UOG disturbances. The invertivore-piscivore metric decreased following UOG disturbance (p = 0.045) whereas two benthic metrics saw a surprising increase (p = 0.003 and p …


Managing Lake Fertility Within The Guidelines Of A Nutrient Management Plan And Based On Algal Nutrient Limitation, Bradley J. Austin, J. Thad Scott, Brian E. Haggard Nov 2018

Managing Lake Fertility Within The Guidelines Of A Nutrient Management Plan And Based On Algal Nutrient Limitation, Bradley J. Austin, J. Thad Scott, Brian E. Haggard

Arkansas Water Resources Center Technical Reports

The specific objectives were to first, monitor nutrients, algal biomass, and water clarity in lakes Cove, Spring, and Wedington. Second, evaluate whether algal growth in each of the lakes was limited by N, P, or both N and P. This research was conducted to help USFS better manage lake fertilization to maximize algal growth and improve the fisheries within these lakes.


Growth Of Pelagic Age-0 Yellow Perch In Relation To Hatch Dates And Water Temperature In North-Central Minnesota Lakes, Ethan Karppinen Aug 2018

Growth Of Pelagic Age-0 Yellow Perch In Relation To Hatch Dates And Water Temperature In North-Central Minnesota Lakes, Ethan Karppinen

Biology Graduate Theses

Exposure to consistent water warming rates and access to abundant populations of edible sized zooplankton affects growth and increases the probability of survival for newly hatched Yellow Perch Perca flavescens. Seven lakes with varying physical characteristics were selected in north-central Minnesota to study abiotic (water temperature) and biotic (zooplankton community and fish growth) progressions during the spring and early summer (April-June). Mean water temperatures from ice-out to 28 June (11.98-14.62 °C) had significant relationships with mean depth (P < 0.01, R? = 0.85), max depth (P < 0.01, R? = 0.73), and total volume (P < 0.01, R2 = 0.54). Hatch periods ranged from 13 to 19 days in 2015 and 13 to 25 days in 2016. Cumulative degree-days (CDD) were used to predict Yellow Perch hatch periods and explain growth. CDD predicted 21-81% of hatch periods in 2015 and 11-50% in 2016. Mean predicted total lengths at 28 June were 19.65-30.41 mm in 2015 and 20.88-28.54 mm in 2016. There was a significant relationship between CDD and predicted total length (R? = 0.62, P < 0.01) to explain differences in Yellow Perch total length while inhabiting the pelagic zone. Observed gape measurements were highly correlated with predicted gapes from the Schael formula (R? = 0.89, P < 0.01) that was used to assess the availability of edible sized zooplankton for age-0 Yellow Perch in each lake. No predator-prey mismatches were found and earlier hatch dates produced age-0 Yellow Perch with greater predicted total lengths in late June on the majority of lakes. This suggests that earlier hatched Yellow perch have an advantage over later hatched Yellow Perch in attaining greater lengths by late June. Our study provides information on a variety of physical and biological progressions in lakes, which may be used for fisheries management practices in the future.


The Importance Of Keeping The Big Ones: Harvest Slot Limits And Marine Protected Areas For The Management Of The Caribbean Spiny Lobster, Gayathiri Gnanalingam Jul 2018

The Importance Of Keeping The Big Ones: Harvest Slot Limits And Marine Protected Areas For The Management Of The Caribbean Spiny Lobster, Gayathiri Gnanalingam

Biological Sciences Theses & Dissertations

Fishing typically removes the oldest and/or largest individuals from populations undermining stability and reproductive success. Traditional fisheries management tools fail to protect these oldest and/or largest individuals, but two less conventional tools: marine protected areas (MPAs), and harvest slot limits have the potential to do so. Here I tested the possible use of these tools for the Caribbean spiny lobster, Panulirus argus, an iconic and economically valued species. After decades of intense fishing, the largest lobsters have largely been wiped out. The loss of the largest lobsters is significant as large lobsters have considerably greater reproductive potential than their …