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Full-Text Articles in Life Sciences
Life History And Fisheries Ecology Of Weakfish, Cynoscion Regalis, In The Chesapeake Bay Region, Susan Lowerre-Barbieri
Life History And Fisheries Ecology Of Weakfish, Cynoscion Regalis, In The Chesapeake Bay Region, Susan Lowerre-Barbieri
Dissertations, Theses, and Masters Projects
Otoliths, scales, dorsal spines, and pectoral fin rays were compared to determine the best hardpart for ageing weakfish, Cynoscion regalis. Sectioned otoliths showed the clearest marks and were validated by the marginal increment method for ages 1-5. Traditionally-used scales were found to be less-precise and to underage older fish. Most weakfish from the Chesapeake Bay region were 200-600 mm TL and ages 1-4. Weakfish were not fully-recruited to commercial foodfish grades until age 2. Maximum observed age was 17 from a Delaware Bay fish collected in 1985. Current maximum observed ages were age 12 in Chesapeake Bay and age 11 …
Contributions To The Early Life Histories Of Alewife (Alosa Pseudoharengus) And Blueback Herring (Alosa Aestivalis): Rearing, Identification, Ageing, And Ecology, Edward Norbert Sismour
Contributions To The Early Life Histories Of Alewife (Alosa Pseudoharengus) And Blueback Herring (Alosa Aestivalis): Rearing, Identification, Ageing, And Ecology, Edward Norbert Sismour
Dissertations, Theses, and Masters Projects
Early life histories of alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis), collectively known as river herring, are poorly documented for Chesapeake Bay populations. Improved knowledge of these early life histories potentially will aid fisheries, habitat and resource management. Investigations were conducted following two lines. First, alewife and blueback herring larvae reared from eggs were used to investigate methods for species identification and to validate the otolith increment method for age determination. Blueback herring larvae hatched from naturally-spawned eggs were reared to age 24 d. Alewife and blueback herring larvae hatched from artificially-spawned eggs were reared to age 32 d …
Use Of A Landscape-Level Approach To Determine The Habitat Requirements Of The Yellow-Crowned Night-Heron, Nycticorax Violaceus, In The Lower Chesapeake Bay, Ellen L. Bentley
Use Of A Landscape-Level Approach To Determine The Habitat Requirements Of The Yellow-Crowned Night-Heron, Nycticorax Violaceus, In The Lower Chesapeake Bay, Ellen L. Bentley
Dissertations, Theses, and Masters Projects
No abstract provided.
Tidal Freshwater Ecosystems: Bibliography, Daniel J. Yozzo, David E. Smith, Marilyn L. Lewis
Tidal Freshwater Ecosystems: Bibliography, Daniel J. Yozzo, David E. Smith, Marilyn L. Lewis
Reports
Tidal freshwater ecosystems represent an important transition zone between saline reaches of estuaries and non-tidal riverine environments. Tidal freshwater systems are distributed worldwide, but have been intensively studied in only a few geographic regions, such as the U.S. east coast and western Europe. Typically, tidal freshwater systems are characterized by high physical stress due to sediment instability and tidal action, which results in low species diversity. However, a number of anadromous and resident fish species utilize tidal freshwater reaches of estuaries as a spawning and nursery area, including economically significant species such as striped bass, American shad, and Atlantic sturgeon. …
Population Genetics Of Selected Species Of Sharks, Edward J. Heist
Population Genetics Of Selected Species Of Sharks, Edward J. Heist
Dissertations, Theses, and Masters Projects
Molecular genetic techniques were used to elucidate genetic population structure in three species of sharks, the coastal sandbar shark (Carcharhinus plumbeus) and Atlantic sharpnose shark (Rhizoprionodon terraenovae), and the pelagic shortfin mako (Isurus oxyrinchus). Allozyme analysis and analysis of restriction fragment length polymorphisms (RFLP) of mitochondrial DNA (mtDNA) were used to test the null hypothesis that the mid-Atlantic Bight and the Gulf of Mexico sandbar sharks consist of a single gene pool. RFLP analysis of mtDNA was used to determine the pattern and level of genetic divergence in the sandbar shark between the western North Atlantic and the Eastern Indian …
Predation On Juvenile Blue Crabs, Callinectes Sapidus Rathbun, In Lower Chesapeake Bay: Patterns, Predators, And Potential Impacts, Kirt E. Moody
Predation On Juvenile Blue Crabs, Callinectes Sapidus Rathbun, In Lower Chesapeake Bay: Patterns, Predators, And Potential Impacts, Kirt E. Moody
Dissertations, Theses, and Masters Projects
Various investigations of the population dynamics of blue crabs in Chesapeake Bay indicate that predator-induced mortality in the juvenile phase may determine year-class strength. In a tethering study, which spanned three seasons in shallow-water habitats of the lower York River, daily mortality rates of juvenile crabs were measured across three variables: crab size (30-70 mm carapace width), habitat type (seagrass, mud, and sand), and month (May-November). Vulnerability to predation was consistently lower for larger crabs, approaching a size refuge from predation at approximately 90 mm carapace width. Predation was most intense in unvegetated sand habitats, and significantly lower in seagrass …
Quantification Of Settlement And Recruitment Processes In Bivalve Mollusks, Patrick Kelly Baker
Quantification Of Settlement And Recruitment Processes In Bivalve Mollusks, Patrick Kelly Baker
Dissertations, Theses, and Masters Projects
Studies were carried out to quantify abundance, mortality, and variability in these parameters, during settlement and recruitment of bivalve mollusks, using the oyster, Crassostrea virginica, as a primary model species. Most work was undertaken in the York River, Chesapeake Bay, Virginia, with additional work in the Indian River, Florida. The period chosen, in the bivalve early life history, was from the late planktonic larva to the early benthic juvenile. Studies were designed to specifically examine (a) abundance of late-stage larvae in the plankton, (b) the relationship between larval abundance and settlement, and (c) mortality immediately following settlement. Variability in abundance …