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William & Mary

Environmental Indicators and Impact Assessment

1987

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Contaminant Effects On Chesapeake Bay Finfishes, Ronald J. Klauda, Michael E. Bender Jan 1987

Contaminant Effects On Chesapeake Bay Finfishes, Ronald J. Klauda, Michael E. Bender

VIMS Books and Book Chapters

Habitat deterioration is consistent with perceived population declines for several resident and anadromous finfish species in Chesapeake Bay that are subjected to different levels of fishing pressure (e.g., striped bass versus blueback herring). Diminution of habitat quality has natural and anthropogenic roots that are difficult to separate. Recent contaminant effects studies focused on Chesapeake Bay fishes can be grouped as follows: (a) mathematical and statistical modeling studies aimed at elucidating contaminant and stock trend relationships using extant data and theoretical insights, (b) biological and chemical field surveys in selected areas to demonstrate spatio-temporal associations between levels of toxic organic and …


Contaminants In Chesapeake Bay: The Regional Perspective, George R. Helz, Robert J. Huggett Jan 1987

Contaminants In Chesapeake Bay: The Regional Perspective, George R. Helz, Robert J. Huggett

VIMS Books and Book Chapters

Industrial and municipal point sources of contaminants are scattered along the shores of Chesapeake Bay and its tributaries, but reach especially high density at Norfolk, Va., and Baltimore, Md. Sedimentation and various chemical processes in many cases conspire to restrict the water-borne transport of contaminant away from point source . Kepone, residual chlorine, volatile halogenated hydrocarbons, and anthropogenic trace metals are well-studied example of point-source contaminants. For the most part, their concentration in water and sediment drop to nearly immeasurable values within a distance of a few kilometers, or sometimes a few tens of kilometers, from their source .

On …


Effects Of Contaminants On Estuarine Zooplankton, Brian P. Bradley, Morrris H. Roberts Jr. Jan 1987

Effects Of Contaminants On Estuarine Zooplankton, Brian P. Bradley, Morrris H. Roberts Jr.

VIMS Books and Book Chapters

The objectives of the chapter are (1) to evaluate laboratory studies concerning effects of heavy metals, pesticides and oxidants on copepods, mysids, bivalve and decapod larvae (2) access field studies (mainly with copepods) on these and other contaminants which when coupled with laboratory data provide information on known and potential hazards of contaminants to zooplankton and (3) briefly review some bioassay methods used in these studies.

Mercury is the most toxic heavy metal by weight, followed by copper, silver and cadmium. Pesticides have been tested much less extensively than heavy metals. In general, bivalve larvae seem less sensitive than the …


Mollusk Culture For The Chesapeake Bay, Michael Castagna Jan 1987

Mollusk Culture For The Chesapeake Bay, Michael Castagna

VIMS Books and Book Chapters

The water quality of the Chesapeake Bay has suffered a decline over the last 5 decades due to anthropomorphic activities. Insidious additions of industrial and farm pollutant to the Bay have created a situation where in many areas there are periodic sub lethal levels of chemicals. Although the juveniles and adults seem to survive these levels, they are obviously interfering with some early life stage of the living organisms that make up the bay fauna. Species whose early life history takes place out of the Bay (i.e. Cal!inectes sapidus) are less affected by this problem than those species whose eggs, …


Contaminant Effects On Chesapeake Bay Shellfish, Michael E. Bender, Robert J. Huggett Jan 1987

Contaminant Effects On Chesapeake Bay Shellfish, Michael E. Bender, Robert J. Huggett

VIMS Books and Book Chapters

The paper reviews contaminant effects on Chesapeake Bay shellfish from two avenues (1) adverse biological effects on the organisms and (2) fisheries closures due to bacterial and chemical contamination. The use of shellfish to monitor anthropogenic inputs of chemical contaminants is also discussed. Fisheries closures due to bacterial contamination account for the greatest economic loss due to man's activities. Kepone contamination in the James River, Virginia caused fisheries closures but has not appeared to cause biological damage to the resources. Organotin compounds from antifouling paints appear to pose a threat to Chesapeake Bay shellfish.


Factors Affecting The Distribution And Abundance Of The Blue Crab In Chesapeake Bay, W. A. Van Engel Jan 1987

Factors Affecting The Distribution And Abundance Of The Blue Crab In Chesapeake Bay, W. A. Van Engel

VIMS Books and Book Chapters

That environmental conditions in the Chesapeake Bay are optimal for the blue crab population is suggested by the fact that hard crab landings by Virginia and Maryland watermen accounted for almost 48% of the total of East and Gulf coast landings in 1985. Estimates of total mortality from the egg to the adult stage range from 0.999973 to 0.999996. Commercial fishing removes an additional 0.0000031 to 0.0000251, leaving 0.0000024 to 0.000001 as the rates of removal by other sources. Physical and chemical pollutants, predators, and plants and animals symbiotic with the blue crab are part of the environment that must …