Study Summary: Fish Community
In the wake of the April 2000 Potomac Electric Power Company (PEPCO) pipeline
oil spill near Benedict, Maryland, the National Oceanic and Atmospheric
Administration (NOAA), the U.S. Fish and Wildlife Service (FWS), the Maryland
Department of Natural Resources (MDNR), and the Maryland Department of the
Environment (MDE) are conducting a natural resource damage assessment (NRDA),
which involves implementing studies to identify and quantify injured resources
and services. This fact sheet provides summary information about one of the
The objectives of this study are to document the relative abundance and
diversity of adult and juvenile fish, fish larvae, and fish eggs
(ichthyoplankton), and compare post-spill abundance and diversity with areas
not affected by the spill and with historic fish community information.
Field protocols were conducted generally as outlined in the Natural Resource
Damage Assessment Emergency Guidance Manual (NOAA 1997). Field surveys
included trawl surveys for adult and juvenile fish and ichthyoplankton tows for
earlier lifestages. Trawl surveys were conducted in the Patuxent River using a
standard 16-foot trawl; they took place for 6 minutes each at 5 stations
between Trueman Point (4 miles upstream from Swanson Creek) and Broomes Island
(11 miles downstream). All fish collected in the trawl were identified by
species, counted, and measured to the nearest centimeter.
Ichthyoplankton surveys were conducted using standard protocols. These surveys
used a midwater trawl with a 0.5-mm mesh plankton net mounted in the trawl.
Tows took place for approximately 5 minutes against the direction of the
current in the Patuxent River between Lyons Creek (approximately 12 miles
upstream) to Sheridan Point (approximately 6 miles downstream). After each tow,
the contents of the plankton net were collected in a sample jar and preserved
in 10-percent buffered formalin until transfer to a laboratory for processing.
Processing consisted of sorting fish eggs and larvae from the debris and
identifying fish specimens by species. Selected species, such as striped bass,
were measured to the nearest millimeter. Results will be compiled and compared
to historic abundance and diversity information and to background areas outside
the spill area.
Eight trawl surveys took place between April 10 and May 10. Between May and
October, six monthly trawl surveys were conducted in the Patuxent River from
Deep Landing downstream to Broomes Island. Analysis of trawl results and
monthly monitoring results will compare post-spill results with historic and
Eleven ichthyoplankton surveys took place between April 10 and May 15; a total
of 68 samples were collected. These samples are currently being processed.
Results will be compared with historic and background conditions.
The trawl and ichthyoplankton sampling plans were developed jointly by the NRDA
Council, which consists of representatives of NOAA, FWS, MDNR, MDE, ST
Services, and PEPCO. Biologists with the MDE Fish Kill Investigation Section
conducted the trawl surveys during the first month of sampling. PEPCO
biologists conducted monthly trawl surveys from May through October as part of
their standard monitoring program. MDNR fisheries biologists conducted
ichthyoplankton surveys. Ichthyoplankton samples are being processed by
Environmental Consulting Services, Inc., of Middletown, Delaware.
For More Information
Contact one of the following individuals or visit a web site for more
NOAA Damage Assessment Remediation and Restoration Program
1305 East West Highway
Building 4, Room 10218
Silver Spring, MD 20910
301.713.3038 x 95
This summary is meant to provide only an overview. More information on NRDA
studies can be found in the Swanson Creek administrative record located at the
Light Point Commerce Center
30383 Three Notch Road
Charlotte Hall, MD
Monday–Friday, 9 a.m. to 5 p.m.
Calvert Industrial Park
230 Bugeye Square
Prince Frederick, MD
Monday–Friday, 9 a.m. to 5 p.m.
Information Resource Center
Maryland Department of Natural Resources
580 Taylor Avenue, B–3
Annapolis, MD 21401
Monday–Friday, 8 a.m. to 4 p.m.