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Long-Distance Dispersal Potential In A Marine Macrophyte, Mc Harwell, R J. Orth

VIMS Articles

Plant populations have long been noted to migrate faster than predicted based on their life history and seed dispersal characteristics (i.e., Reid's paradox of rapid plant migration). Although precise mechanisms to account for such phenomena are not fully known for all plant species, a combination of theoretical and empirically driven mechanisms often resolves this paradox. Here, we couple a series of direct and indirect field and laboratory exercises on one marine macrophyte, Zostera marina L. (eelgrass), to measured distances between new patches and established beds in order to elucidate the longdistance dispersal and colonization potential of this marine seagrass. Detached, …

Restoration Of Submerged Aquatic Vegetation (Sav) In The Tidal Freshwater James River: Year 3, Kenneth A. Moore, Britt Anderson, Betty Neikirk

Reports

No abstract provided.

Reproduction Of Black Drum, Pogonias Cromis, From The Chesapeake Bay Region, Brian K. Wells, Cynthia M. Jones

Virginia Journal of Science

Ovaries of black drum, Pogonias cromis, collected from the Chesapeake Bay region in 1992, were used to describe reproductive strategy and fecundity. Histological examination showed that black drum spawn in the Chesapeake Bay region from April through early June. Distributions of oocyte diameter showed distinct oocyte-developmental groups indicating that Chesapeake Bay black drum are group-synchronous batch spawners. Female black drum are extremely fecund ranging from 414,000 to 3,736,000 hydrated oocytes (mean = 1,389,000) per batch with a spawning periodicity of 3.8 days. Estimates of spawning strategy, spawning periodicity, and batch fecundity for black drum from the Chesapeake Bay region …

Summer Vertical Phytoplankton Distribution In The Lower Chesapeake Bay, Mollie Jill Weinstein

Biological Sciences Theses & Dissertations

Autotrophic picoplankton and phytoplankton composite samples were collected from the surface, pycnocline, and bottom water layers at three stations in the lower Chesapeake Bay between June and September 1993. Using light microscopy a total of 170 phytoplankton taxa were identified. Utilizing epifluorescent microscopy, the picoplankton taxa were distinguished by size, representing species with cells less than 2 microns. Diatoms were the dominant taxa during this period, with lesser representation by the other phytoplankton components. Within the picoplankton category, cyanobacteria were dominant. Statistical analyses of the data indicated the vertical composition and abundance of the phytoplankton was not significantly different over …

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 …

Settlement And Survival Of The Oyster Crassostrea Virginica On Created Oyster Reef Habitats In Chesapeake Bay, Janet A. Nestlerode, Mark W. Luckenbach, Robert J. Diaz

Reports

Efforts to restore Crassostrea virginica oyster reef habitats in Chesapeake Bay typically begin with the placement of hard substrata, such as oyster shell, in the form ofthreedimensional mounds on the seabed to serve as a base for oyster recruitment and growth. A shortage of sufficient volumes of oyster shell for creating large-scale reefs has led to widespread use of other materials, such as surf clam (Spisula solidissima) shell, as a substitute for oyster shell. We monitored oyster recruitment, survival, and growth on intertidal and subtidal reefs constructed shucked oyster and surf clam shell. Results indicate that oyster settlement occurred on …