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Full-Text Articles in Physical Sciences and Mathematics
Studies Of Mortality Estimation, Amy Y. Then
Studies Of Mortality Estimation, Amy Y. Then
Dissertations, Theses, and Masters Projects
Instantaneous total mortality rate Z can be partitioned into two components: fishing, F, and natural mortality, M. A number of data-poor methods have been developed to estimate Z, F, and M, and these methods tend to rely on fairly restrictive assumptions as well as on data types that are easy to obtain, e.g., length or other life history information. The overarching goal of this dissertation is to contribute to the advancement of methods for estimating these important and influential stock parameters. The relevant issues and the gaps in knowledge pertaining to these data-poor methods are outlined in the Introduction chapter …
Effects Of Saltwater Intrusion On Vegetation Dynamics And Nutrient Pools In Low-Salinity Tidal Marshes, Pamunkey River (Virginia, Usa), Lori A. Sutter
Effects Of Saltwater Intrusion On Vegetation Dynamics And Nutrient Pools In Low-Salinity Tidal Marshes, Pamunkey River (Virginia, Usa), Lori A. Sutter
Dissertations, Theses, and Masters Projects
This study investigated vegetation changes in a former tidal freshwater marsh (TFM) to determine the role that salinity intrusion plays in vegetation dynamics. Field observations along a narrow salinity gradient in the Pamunkey River revealed that vegetation is shifting to fewer dominants with increasing salinity. Two remaining dominants, Peltandra virginica and Zizania aquatica (hereafter Peltandra and Zizania, respectively), had variable net CO2 assimilation throughout the growing season. Peltandra net CO2 assimilation declined both over the growing season and in marshes with higher salinity; whereas, Zizania generally increased over the growing season peaking in late summer. The same species' tissue nutrients …
Physiological Stress And Post-Release Mortality Of White Marlin (Kajikia Albida) Caught In The U.S Recreational Fishery, Lela Sylvia Schlenker
Physiological Stress And Post-Release Mortality Of White Marlin (Kajikia Albida) Caught In The U.S Recreational Fishery, Lela Sylvia Schlenker
Dissertations, Theses, and Masters Projects
White Marlin (Kajikia albida) is a highly migratory species that occurs throughout temperate and tropical regions of the Atlantic Ocean and is the basis of a large sport fishery along the United States Atlantic coast. The single, Atlantic-wide stock is considered to be overfished, with less than one-third the spawning biomass estimated to be necessary for maximum sustainable yield. Billfish management measures adopted by the International Commission for the Conservation of Atlantic Tunas (ICCAT) and implemented in the U.S. by the National Marine Fisheries Service (NMFS), as well as increasing angler awareness of conservation, have resulted in the vast majority …
An Evaluation Of A Reduced Bar Spacing Turtle Excluder Device In The U.S Gulf Of Mexico Offshore Shrimp Trawl Fishery, Michel Anthony Nalovic
An Evaluation Of A Reduced Bar Spacing Turtle Excluder Device In The U.S Gulf Of Mexico Offshore Shrimp Trawl Fishery, Michel Anthony Nalovic
Dissertations, Theses, and Masters Projects
Shrimp are the most economically valuable internationally-traded seafood commodity, and wild-caught, trawled shrimp make up almost half of the ~6.6 million metric tons of annual global production. Shrimp trawling is responsible for one-third of the world’s total fisheries bycatch, leading many to consider shrimp trawling to be the single most destructive fishing practice in the world. Though the bycatch of large marine animals can be significantly reduced by use of turtle excluder devices (TEDs) on shrimp trawls, current TED designs are ineffective at reducing the capture of smaller organisms which represent a large portion of the total bycatch. To further …
Fishes In Seagrass Habitats: Species Composition, Trophic Interactions, And Production, Kathryn L. Sobocinski
Fishes In Seagrass Habitats: Species Composition, Trophic Interactions, And Production, Kathryn L. Sobocinski
Dissertations, Theses, and Masters Projects
The value of habitats in terms of biological production is of interest to ecologists and resource managers. Seagrasses are a commonly occurring habitat type in shallow marine waters and have been shown to support high abundances of fish and invertebrates. In lower Chesapeake Bay, seagrasses grow in a shallow fringe in the subtidal zone. Although, ample evidence exists for the value of these habitats as foraging and rearing areas for a variety of organisms, the connectivity among species and the benefits derived from these habitats in terms of production have not been well described, especially for small, seasonally occurring finfishes. …
Factors Influencing Year-Class Strength And Growth Of Young-Of-The-Year Summer Flounder (Paralichthyidae: Paralichthys Dentatus), Lauren N. Nys
Factors Influencing Year-Class Strength And Growth Of Young-Of-The-Year Summer Flounder (Paralichthyidae: Paralichthys Dentatus), Lauren N. Nys
Dissertations, Theses, and Masters Projects
No abstract provided.
Quantification Of Nursery Habitats For Blue Crabs In Chesapeake Bay, Gina M. Ralph
Quantification Of Nursery Habitats For Blue Crabs In Chesapeake Bay, Gina M. Ralph
Dissertations, Theses, and Masters Projects
The blue crab is an iconic species in Chesapeake Bay, supporting important commercial and recreational fisheries and functioning as a critical link in the food web. Structurally complex habitats are often cited as nurseries for the blue crab, and other commercially important fish and crustacean species, by providing enhanced growth and survival for juveniles. I quantified the value of shallow habitats as nurseries for blue crabs through field studies and a demographic model. In Chapter 2, I utilized a two-year juvenile survey in vegetated habitats of the lower Bay to examine the effect of habitat complexity on the density of …