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Atlantic Seaduck Project: Chesapeake Bay Ecosystem Model

 

Background:
Seaducks (goldeneyes, bufflehead, harlequin duck, eiders, long-tailed duck, scoters, and mergansers) are the most poorly understood group of North American waterfowl.  Surveys of seaducks have revealed that populations have declined for 13 out of 15 species.  There has been increased concern for the status of seaducks in general by managers throughout the continent.  Populations of the spectacled eider and Steller’s eider are declared threatened under the authority of the U.S. Endangered Species Act.  Four additional species, common eider, king eider, long-tailed duck, and black scoter are at risk and deserve immediate attention.  Surveys of seaducks wintering on the Atlantic coast have shown major declines for the long-tailed duck, black scoter, and surf scoter.  The Chesapeake Bay is an important wintering area for the three scoter species and the long-tailed duck. However, the Chesapeake Bay has undergone extensive changes in habitat available to wintering waterfowl due to the degradation of water quality.  There are a number of hypotheses being researched to determine the cause or causes of the overall decline of seaducks, which include contaminants on the staging and breeding areas, lower recruitment, food availability changes in wintering areas (and therefore greater energetic costs of migration), and anthropogenic factors such as increased hunting pressure and boating activity.
The Atlantic Seaduck Project has been the primary research of the Atlantic Coast populations of seaducks, and has focused on the three scoter species and the long-tailed duck.  For the past four years we have been collecting satellite telemetry data on these species to determine their migrational pathways and habitats used.  We are presently sampling the benthos in the major areas along their migration to evaluate the availability and energetic quality of their primary food resources.  We have also collected hunter killed ducks to determine their food habits along their migration. 
Ultimately, we are going to create a Chesapeake Bay ecosystem model, which combines all our research findings and the results from other Chesapeake Bay studies that would have an affect on the seaduck populations, such as sea level rise, recreational use, and water quality.  We hypothesize that seaducks can be used as reliable indicator species for the overall health of the deepwater habitats of the Chesapeake Bay.  We hope that managers will be able to apply this model to develop better management practices to help restore the dwindling Atlantic coast populations of seaducks and thereby restore the health of the Chesapeake Bay overall.
Diagram of Atlantic Seaduck Project: Chesapeake Bay Ecosystem Model
Objectives:
1.  Compile all present data on seaducks wintering on the Chesapeake Bay.
2.  Compile all data on abiotic factors that influence seaduck food resources.
3.  Create a simulation model to enhance seaduck management and predict the
     effects of Bay restoration efforts on seaduck populations wintering on the Bay.

Methods:

There are five main components of this system: 1) productivity model, 2) mortality model, 3) energetics model, 4) habitat model, and 5) present population survey data.  Some of this information will be computer simulated and some provided by field research.  The productivity model will be created based on the information available, which is very scarce.  The Atlantic Seaduck Project is in the process of classifying the breeding habitats used by black and surf scoters.  There is a definite need for more information on the breeding biology of the Atlantic Flyway seaduck populations.  The mortality model will be based on data collected from various sources, the Bird Banding Laboratory, and other USGS disciplines.  A PhD graduate student at Patuxent Wildlife Research Center (PWRC) working with a captive seaduck colony is creating the energetics model.  The habitat model is being created by a MS graduate student at PWRC working with the benthic ecosystem of the Chesapeake Bay.  Both models will be incorporated in the population model when they are completed.  These components when incorporated into a population simulation model will allow managers to alter different factors and enable them to predict the effects of those alterations on the wintering seaduck populations.  We will run simulations of different restoration efforts that are being implemented on the Chesapeake Bay at this time to predict the effects of these efforts on the wintering seaduck populations.  The primary focus will be on benthic ecosystem productivity resulting from changes in water quality through nutrient regulations.  Hopefully these changes will directly benefit seaduck populations in Chesapeake Bay and
provide positive societal impacts for all residents in the large Bay watershed.    

Male White-winged Scoter
Male White-winged Scoter
Juvenile White-winged Scoter
Juvenile White-winged Scoter
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