Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Marine Biology
Ecology And Conservation Of Virginia Shark Species: Analysis Of Thirty Years Of Virginia Long-Line Shark Census Data, 1974--2004, Daniel Stuart Ha
Ecology And Conservation Of Virginia Shark Species: Analysis Of Thirty Years Of Virginia Long-Line Shark Census Data, 1974--2004, Daniel Stuart Ha
Dissertations, Theses, and Masters Projects
Sharks of the Atlantic coast of the United States have suffered increased fishing pressure in last three decades. Commercial and recreational catches jumped in the mid to late 1980's, leading to regulation by the National Marine Fisheries Service in the early 1990's. The Virginia Institute of Marine Sciences' shark long-line survey, begun in 1974, and continuing to the present day, is thus well positioned to look at the effects of this fishing mortality on sharks. Using GAM modelling, six of ten shark species analyzed, including the most common species, Carcharhinus plumbeus, suffered declines of from 98-99% of early abundances in …
Sources Of Mortality, Movements And Behavior Of Sea Turtles In Virginia, Katherine Lamont. Mansfield
Sources Of Mortality, Movements And Behavior Of Sea Turtles In Virginia, Katherine Lamont. Mansfield
Dissertations, Theses, and Masters Projects
Aerial surveys are commonly used to evaluate in-water sea turtle abundances. A correction is applied to account for turtles diving below the observed surface. Historically, observations of summer/fall surfacing behavior were used for this correction, assuming constant behavior among seasons. Using radio/acoustic telemetry, seasonal differences in sea turtle surfacing behavior were determined among Kemp's ridleys and loggerheads. Mean time spent at surface in the spring ranged between 9.9%-30.0% with significant differences among individuals. Observed surfacing times were higher than historic summer/fall observations (Byles 1988; 5.3%), indicating that historic springtime abundances were overestimated by 50%-80%. Aerial surveys (2001-2004) indicated a 65%-75% …