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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #152355

Title: UNDERSTANDING THE "WHO, WHAT, WHERE AND WHY" OF COUNTING DOUBLE-CRESTED CORMORANTS WITHIN AQUACULTURE PRODUCTION AREAS.

Author
item RADOMSKI, ANDREW
item FREEMAN, DONALD

Submitted to: Catfish Farmers of Arkansas
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2002
Publication Date: 1/30/2003
Citation: RADOMSKI, A.A., FREEMAN, D.W. UNDERSTANDING THE "WHO, WHAT, WHERE AND WHY" OF COUNTING DOUBLE-CRESTED CORMORANTS WITHIN AQUACULTURE PRODUCTION AREAS.. CATFISH FARMERS OF ARKANSAS. 2003. p.2.

Interpretive Summary:

Technical Abstract: Increasing numbers of double-crested cormorants at commercial aquaculture ponds have resulted in biological, economical, and social conflicts. Aerial surveys by fixed-wing aircraft by USDA-ARS were conducted to monitor the wintering cormorant numbers from 1999-2002. A minimum of 2 surveys per month was conducted along a fixed route. Survey flights were conducted on consecutive days. Aerial counts were validated with ground observations the following morning at specific roosts for accuracy. A minimum of 16,000 cormorants was observed during each survey, with the exception of early January 2000 and 2001, and late February 2002. Cormorant numbers peaked (>26,000) in early February 2001 and early March 2002. A total of 72 night roost sites were monitored during 1999-2002. Cormorants roosted in bald cypress trees almost exclusively. Some roosts were protected from human disturbances, but some were adjacent to highways or adjacent to high recreational areas. Similarities in numbers of cormorants counted in the evening by aircraft and the following morning by ground observers at the same roost allows for increased confidence that the estimates are reasonably accurate. It is important to monitor cormorants to better understand the population trends, movements during the winter, roost site selection, roosting behavior, and changes that may occur with a national, regional, state, or local management plan.