Physical Sciences and Mathematics Commons^™

Vertical Distributions Of Zooplankton At The Mouth Of Chesapeake Bay And Calibration Of Backscatter From An Acoustic Doppler Current Profiler, Arthur Keith Jenkins

Biological Sciences Theses & Dissertations

This study investigated the physical factors influencing the vertical distribution of zooplankton at the mouth of the Chesapeake Bay and attempted to derive biological data from acoustic Doppler current profiler (ADCP) backscatter. A single site was occupied in the North Channel at the mouth of Chesapeake Bay (37° 04' N, 75° 58' W) from 17.0–19.7 November 1999. Temperature, salinity, fluorescence, light transmission, current velocity and backscatter were measured throughout the sampling period. Plankton samples were collected every hour from 3.5, 7.5, and 11.5 m.

We found little association between ADCP backscatter and plankton concentrations, but stronger correlations between backscatter and …

Status Of The Major Oyster Diseases In Virginia 2001 A Summary Of The Annual Monitoring Program, Lisa M. Ragone Calvo, Eugene M. Burreson

Reports

Thirty-nine oyster populations were surveyed for disease in fall 2001. Perkinsus marinus was found in all areas sampled and prevalence exceeded 90% at all but 5 sample locations. In the James River P. marinus prevalence ranged from 88-100% at Deepwater Shoal, Horsehead Rock, Point of Shoals, Wreck Shoal, Mulberry Point, Swash, Long Shoal, and Dry Shoal. A lower prevalence was observed down river at Thomas Rock, 72%, and at Nansemond Ridge, 12%. The extremely low prevalence at Nansemond Ridge is likely age and density related; the oyster population was primarily comprised of spat; few small to market oysters were present …