| Abstract: | In January 2001, the construction of the Davis Pond
freshwater diversion structure was completed by the U.S.
Army Corps of Engineers. The diversion of freshwater
from the Mississippi River is intended to mitigate saltwater
intrusion from the Gulf of Mexico and to lessen the
concomitant loss of wetland areas. In addition to the
freshwater inflow, Barataria Bay basin would receive
nutrients, increased flows of sediments, and water-borne
and sediment-bound compounds. The purpose of this
biomonitoring study was, therefore, to serve as a baseline for
prediversion concentrations of selected contaminants in bald
eagle (Haliaeetus leucocephalus) nestlings (hereafter referred
to as eaglets), representative freshwater fish, and bivalves.
Samples were collected from January through June 2001. Two
similarly designed postdiversion studies, as described in the
biological monitoring program, are planned.
Active bald eagle nests targeted for sampling eaglet
blood (n = 6) were generally located southwest and south
of the diversion structure. The designated sites for aquatic
animal sampling were at Lake Salvador, at Lake Cataouatche,
at Bayou Couba, and along the Mississippi River. Aquatic
animals representative of eagle prey were collected. Fish
were from three different trophic levels and have varying
feeding strategies and life histories. These included
herbivorous striped mullet (Mugil cephalus), omnivorous
blue catfish (Ictalurus furcatus), and carnivorous largemouth
bass (Micropterus salmoides). Three individuals per species
were collected at each of the four sampling sites. Freshwater
Atlantic rangia clams (Rangia cuneata) were collected at the
downstream marsh sites, and zebra mussels (Dreissena spp.)
were collected on the Mississippi River.
The U.S. Geological Survey (USGS) Biomonitoring of
Environmental Status and Trends (BEST) protocols served
as guides for fish sampling and health assessments. Fish
are useful for monitoring aquatic ecosystems because they
accumulate pesticides and other contaminants. Biomarker
data on individual fish, generated at the USGS National
Wetlands Research Center (Lafayette, La.), included percent
white blood cells in whole blood, spleen weight to body
weight ratio, liver weight to body weight ratio, condition
factor, splenic macrophage aggregates, and liver microsomal
7-ethoxyresorufin-o-deethylase (EROD) activity. Fish
age was estimated by comparing total lengths with values
from the same species in the Southeast United States as
determined from the literature. Contaminant analyses were
coordinated by the U.S. Fish and Wildlife Service (USFWS)
Analytical Control Facility (Laurel, Md.), where residues
of organochlorine (OC) pesticides, total polychlorinated
biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs),
aliphatic hydrocarbons (AHs), and trace elements were
determined. The organic contaminant data were generated at
the Mississippi State University Chemical Lab (Mississippi
State, Miss.), and the inorganic contaminant data were
generated by the Texas A&M University Geochemical and
Environmental Research Group (College Station, Tex.).
Statistical tests were performed to assess relationships among
contaminants, fish age, fish species, and collection sites. |
| Genre: | USGS Numbered Series |
| ProdID: | 97208 |
| Citation Author: | Jenkins, Jill A.; Bourgeois, E. Beth; Jeske, Clint W. |
| Citation Contributing Office: | National Wetlands Research Center |
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| Citation Language: | ENGLISH |
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| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | vi, 102 p. |
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| Citation Public Comments: | Prepared in cooperation with the Louisiana Department of Wildlife and Fisheries, the U.S. Army Corps of Engineers, and the U.S. Fish and Wildlife Service (USFWS) |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Scientific Investigations Report |
| Citation Series Code: | SIR |
| Citation Series Number: | 2008-5067 |
| Citation Search Results Text: | Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles; 2008; SIR; 2008-5067; Jenkins, Jill A.; Bourgeois, E. Beth; Jeske, Clint W. |
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| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles; 2008; SIR; 2008-5067; Jenkins, Jill A.; Bourgeois, E. Beth; Jeske, Clint W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/sir/2008/5067/ |
| Date Other: | Sat, 10 Jan 2009 00:00 -0600 |
| Publisher: | U.S. Geological Survey |
