Fresh Water Studies Commons^™

Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk

Watershed Sciences Faculty Publications

Examples from fishless aquatic habitats show that competition among zooplankton for resources instigates rapid exclusion of competitively inferior species in the absence of fish predation, and leads to resource monopolization by the superior competitor. This may be a single species or a few clones with large body size: a cladoceran such as Daphnia pulicaria, or a branchiopod such as Artemia franciscana, each building its population to a density far higher than those found in habitats with fish. The example of zooplankton from two different fish-free habitats demonstrates the overpowering force of fish predation by highlighting the consequences of its absence. …

The Life History Of Longnose Gar, Lepisosteus Osseus, An Apex Predator In The Tidal Waters Of Virginia, Patrick E. Mcgrath

Dissertations, Theses, and Masters Projects

Longnose gar (Lepisosteus osseus) inhabit all of the major tributaries of Chesapeake Bay in Virginia, extending from fresh to estuarine waters. Literature concerning longnose gar from tidal environments is limited and this is study concerns important aspects of the life history (e.g., growth, reproduction, dimorphism, movements, and diet). Age, growth, and reproduction are important life history aspects for understanding the biology of fishes and may be affected by the environment in which an individual lives. This study found no differences in the age, growth, and fecundity parameters between longnose gar from tidal portions of Chesapeake Bay tributaries and previous studies …

Tributary Contribution To The Spring River, Ar As Determined By Water Quality Analyses, T. R. Brueggen, C. B. Dowling, Jennifer L. Bouldin

Journal of the Arkansas Academy of Science

Tributaries often play an important role in the chemical properties, productivity and species diversity in a river channel. The objective of this study was to analyze the effect of tributaries on the water quality of the Spring River, AR. The Spring River has an approximate length of 92 km and has been divided into four zones according to the water source(s) that feed that segment of river. In this study approximately 30 km of the upstream river segment were sampled, which included nine tributaries contributing to the main river channel and incorporated the upper three previously defined zones. Samples were …

Managing Drought Risk On The Ranch: A Planning Guide For Great Plains Ranchers, University Of Nebraska - Lincoln National Drought Mitigation Center

National Drought Mitigation Center: Publications

TABLE OF CONTENTS

WHY PLAN FOR DROUGHT?......... 3

UNDERSTANDING DROUGHT........... 6

THE RANCH DROUGHT PLAN........... 9

COMMUNICATION AND PLANNING PARTNERS............ 10

RANCH VISION AND OBJECTIVES............. 11

SWOT ANALYSIS............... 12

INVENTORY OF RANCH RESOURCES................ 13

CRITICAL DATES AND TARGET POINTS................. 15

MONITORING PLAN AND SCHEDULE.................... 19

EVALUATE DROUGHT MANAGEMENT STRATEGIES............ 20

IMPLEMENT AND MONITOR THE DROUGHT PLAN............ 29

WORKSHEETS........... 30

State Of The River Report For The Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, And Contaminants 2010, Environmental Protection Board, City Of Jacksonville, University Of North Florida, Jacksonville University

State of the River Report

No abstract provided.

Accounting For Undesirable Outputs In Productivity Measurements: Application To The California-Oregon Drift Gillnet Fishery, Tara L. Scott

Dissertations, Theses, and Masters Projects

Many production activities typically produce undesirable outputs, e.g., the production of the pollutant sulfur dioxide in the generation of electricity. Traditional economic metrics may overstate the efficiency and productivity of these production activities by failing to account for the undesirable outputs. These omissions can lead to conclusions that are biased against resource conservation and protection. Many fisheries capture their target species concomitantly with undesirable outputs such as bycatch of juvenile fish, marine mammals, sea birds, and sea turtles. One such fishery is the California-Oregon (CA/OR) drift gillnet fishery (DGNF), which incidentally takes protected species, such as sea turtles and marine …

Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Deborah A. Bronk, Quinn N. Roberts, Marta P. Sanderson, Elizabeth A. Canuel, Patrick G. Hatcher, Rajaa Mesfioui, Katherine C. Filippino, Margaret R. Mulholland, Nancy G. Love

Chemistry & Biochemistry Faculty Publications

The goal of this study was to investigate three potential ways that the soluble organic nitrogen (N) fraction of wastewater treatment plant (WWTP) effluents, termed effluent organic N (EON), could contribute to coastal eutrophication - direct biological removal, photochemical release of labile compounds, and salinity-mediated release of ammonium (NH₄+). Effluents from two WWTPs were used in the experiments. For the bioassays, EON was added to water from four salinities (∼0 to 30) collected from the James River (VA) in August 2008, and then concentrations of N and phosphorus compounds were measured periodically over 48 h. Bioassay results, based …

Incorporating Industry Based Dredge Surveys Into The Assessment Of Sea Scallops, Placopecten Magellanicus, David B. Rudders

Dissertations, Theses, and Masters Projects

Cooperative research utilizing industry vessels represents a viable approach to acquire the data necessary to meet the increasing needs associated with the modern management of marine resources. This dissertation addresses a variety of topics associated with the integration of commercial vessels into the stock assessment of the sea scallop, Placopecten magellanicus. In this study we evaluate the efficacy of utilizing industry vessels with respect to topics that range from rotational closed area survey design, sampling gear evaluation as well as an experiment that broadens the scale of the traditional use of industry vessels in this fishery and provides data to …

"You Have No Boss Here To Work For": Women And Labor In Chesapeake Bay Fishing Communities, Elizabeth Marie O'Grady

Dissertations, Theses, and Masters Projects

No abstract provided.

Temporal Controls On Dissolved Organic Matter And Lignin Biogeochemistry In A Pristine Tropical River, Democratic Republic Of Congo, Robert G. M. Spencer, Peter J. Hernes, Rosmarie Ruf, Andy Baker, Rachael Y. Dyda, Aron Stubbins, Johan Six

Chemistry & Biochemistry Faculty Publications

Dissolved organic carbon (DOC), lignin biomarkers, and the optical properties of dissolved organic matter (DOM) were measured in the Epulu River (northeast Democratic Republic of Congo) with the aim of investigating temporal controls on the quantity and chemical composition of DOM in a tropical rainforest river. Three different periods defined by stages of the hydrologic regime of the region, (1) post dry flushing period, (2) intermediary period, and (3) start of the dry period/post flush, were sampled. Temporal variability in DOM quantity and quality was observed with highest DOC, lignin concentration (Σ₈) and carbon‐normalized (Λ₈) values …

Estimating Detection Probabilities In Beach Seine Surveys For Estuarine Fishes, Branson D. Williams

Dissertations, Theses, and Masters Projects

Detectability, the probability that a species is encountered if it inhabits a site, is often overlooked in fisheries research despite its potential to obscure habitat use inferences. Detectability can be estimated using models that also provide an estimate of occupancy (Ψ), the probability that a species inhabits a site. I used these models to estimate both probabilities, and to examine factors affecting detectability and occupancy for three fishes in Chesapeake Bay tributaries: young-of-the-year striped bass (Morone saxatilis), yearling Atlantic croaker (Micropogonias undulatus), and spottail shiner (Notropis hudsonius). Occupancy models were fitted to data from a seine survey conducted during summer, …

The Effect Of Salinity On Experimental Hematodinium Sp Infections In The Blue Crab, Callinectes Sapidus, Anna Huntley Coffey

Dissertations, Theses, and Masters Projects

No abstract provided.

The Influence Of Nutrients And Physical Habitat In Regulating Algal Biomass In Agricultural Streams, Mark D. Munn, Jeffrey Frey, Anthony Tesoriero

United States Geological Survey: Water Reports and Publications

This study examined the relative influence of nutrients (nitrogen and phosphorus) and habitat on algal biomass in five agricultural regions of the United States. Sites were selected to capture a range of nutrient conditions, with 136 sites distributed over five study areas. Samples were collected in either 2003 or 2004, and analyzed for nutrients (nitrogen and phosphorous) and algal biomass (chlorophyll a). Chlorophyll a was measured in three types of samples, fine-grained benthic material (CHLFG), coarse-grained stable substrate as in rock or wood (CHLCG), and water column (CHLS). Stream and riparian habitat were characterized at each site. TP ranged from …

Exploring The Potential For Bay Scallop Restoration In The Lynnhaven River Sub-Estuary Of Chesapeake Bay, Ana Liza Hernandez Cordero

Dissertations, Theses, and Masters Projects

No abstract provided.

Partial Year Tagging Models: Accounting For Changing Tag Visibility And Delayed Mixing, Lynn Waterhouse

Dissertations, Theses, and Masters Projects

No abstract provided.

Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell

Dissertations, Theses, and Masters Projects

Complex oyster reefs created by the Eastern oyster, Crassostrea virginica, though once prominent features of the Chesapeake Bay region, have become relatively scarce in comparison to historic descriptions. This decline, caused by a combination of overfishing, disease, habitat destruction and pollution, this decline continues despite substantial restoration efforts that have spanned decades. In response to this decline, the states of Virginia and Maryland considered the intentional introduction of the non-native Suminoe oyster, C. ariakensis. Previous studies questioned the reef-building capability of this Crassostrea species, which may affect its habitat function. Through a combination of field and mesocosm studies, I examined …