Brown Bullhead Catfish Studies

Map of regions of concern in the Chesapeake Bay Region
Brown bullhead catfish with mouth tumor

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Nesting Osprey Exposure to Contaminants

Photograph by James Forester, USFWS

Does being in a region of concern cause tumors in brown bullhead catfish? (title)

Brown Bullhead Studies in the
Chesapeake Bay Regions of Concern

Baltimore Harbor and the Anacostia River are two of the three Regions of Concern in the Chesapeake Bay, designations based on chemical contaminant concentrations in sediments. Chesapeake Bay Field Office Environmental Contaminants Specialists have conducted several studies with brown bullheads (Ameiurus nebulosus) to determine if these contaminants are affecting the health of fish populations.

In 1996, biologists collected four groups of brown bullheads from the tidal Potomac watershed to look for tumors in relation to contaminant exposure. These bottom feeding fish were collected from the Quantico embayment, near a Superfund site which released polychlorinated biphenyls (PCBs) and DDT compounds; Neabsco Creek, a tributary with petroleum inputs from upstream areas and marinas; and the Anacostia River (both in spring and fall), where sediment is contaminated with polynuclear aromatic hydrocarbons (PAHs), PCBs, and organochlorine pesticides. A fifth group was collected from the Tuckahoe River on Maryland’s Eastern Shore as a reference. Fish were examined for liver and skin tumors.

Fifty percent of Anacostia fish caught in the spring and 60% of those caught in fall had liver tumors compared to 17% from Neabsco Creek, 7% from Quantico and 10% from Tuckahoe River. Biologists also found that 37% of Anacostia fish caught in spring and 10% of those caught in fall had skin tumors compared to only 3% from Neabsco Creek and Quantico and none from Tuckahoe River.

The number of Anacostia fish with tumors is similar to those at contaminated sites in the Great Lakes and warrants concern. PAH concentrations were significantly higher in Anacostia sediments than at the other sites. At present, there are insufficient data, however, to establish a cause and effect link with a particular class of contaminants. Chesapeake Bay Field Office recommends using tumor studies to monitor the health of resident fish and as a tool to evaluate the success of clean up efforts.

In 1998, bullheads were collected near Baltimore Harbor from Furnace Branch, a tributary to the Patapsco River, and Back River to study tumor prevalence near this urban area.. Bullheads were also collected from the Tuckahoe River as a reference. Data analyses are in progress.

The use of the brown bullhead as an environmental indicator requires that scientists have an understanding of fish movements so that the exposure area can be estimated. Chesapeake Bay Field Office Environmental Contaminants Specialists, in collaboration with Dr. Roman Jesien of the University of Maryland Eastern Shore, are using ultrasonic transmitters to track the movements of bullheads in the Anacostia River. This study is in progress..