Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 10 of 10 for “"trawl survey"”.
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Bycatch associated with a horseshoe crab (Limulus polyphemus) trawl survey: identifying species composition and distribution
… or quantify bycatch in the horseshoe crab trawl fishery. A horseshoe crab trawl survey was started in 2001 to collect data on the relative abundance, distribution, and population demographics of horseshoe crabs along the Atlantic coast of the United States. In the present study, species …
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Historical baselines and a century of change in the demersal fish assemblages on South Africa's Agulhas Bank
… A remarkably detailed set of historical trawl survey data from South Africa provided such a rare opportunity. Government-funded exploration of the Agulhas Bank fishery potential resulted in meticulously-documented trawl survey data from 1897-1904, when prior human impacts on those …
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Addressing the impact of the EU CFP landing obligation on the northern North Sea ecosystem and Shetland fisheries in a changing climate.
… assessments and North Sea International Bottom Trawl Survey (NS IBTS) data, tailored discard estimations and fish stomach records (from Cefas DAPSTOM–supplemented by Shetland UHI: Shetland food web biodiversity and trophic interactions project 2017). Retrospective analysis of environmental …
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Modelling changes in the growth, maturity, and abundance of fish in Scottish waters
… separately in each chapter. Scientific bottom trawl survey data were used to examine changes in growth rates and maturation scheduling. Trends in growth rates were determined by calculating time series of mean lengths-at-age and von Bertalanffy growth parameters. Probabilistic maturation …
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Assessing the effects of fishing on fish communities using South African case studies : empirical and theoretical approaches
… for the line fishery and analysis of demersal trawl survey data from the south coast of South Africa, and analysis of output of the Individual Based Model OSMOSE applied to the southern Benguela. Structural changes in the landings from the line fishery and south coast survey data are assessed …
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Challenges in Reconstructing Past Exploitations of Atlantic Cod: A Zooarchaeological Case Study from Early Medieval England
… cod sizes were further compared to modern trawl survey data. A significant temporal decrease was observed between both archaeological datasets and the modern data. The larger archaeological cod body sizes suggest significantly improved weights, reproductivity, and health of cod populations …
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Striped Bass and Summer Flounder Population Dynamics in the Chesapeake Bay: an Ecosystem Based Evaluation
… Bay from two sources of fishery-independent trawl survey data. This standardization process led to relative abundance indices for 58 late juvenile to adult species from 2002-2018, and relative abundance indices for 26 juvenile species from 1995-2019. Species with similar and contrary …
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Drivers and effects of plastic contamination in aquatic ecosystems
… the framework of the MEDiterranean International Trawl Survey. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. The data shows how different sources and physical …
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Enviromental influences on the spatio-temporal distribution of Aristeus Antennatus (Risso, 1816) and Aristaeomorpha Foliacea (Risso, 1827) in the Central-Western Mediterranean
… the remaining 17% non-fully exploited. Bottom trawling fleets predominate in many Mediterranean fisheries, being responsible for a high share of total catches and, in many cases, yielding the highest earnings among all the fishing sub-sectors. The deep-sea fishing began only in the first …
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A mid-Atlantic study of the movement patterns and population distribution of the American horseshoe crab (Limulus polyphemus)
… as possible locations for annual spawning surveys. Twelve thousand five hundred horseshoe crabs were tagged and released in Chincoteague, Virginia and Ocean City, Maryland as part of a movement study; 431 (3.45%) were reported as resights. The mean distance between site of release and site …