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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #146902
Title: THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS WITHIN AQUACULTURE PRODUCTION AREAS.

Author
item Radomski, Andrew
item Freeman, Donald

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2003
Publication Date: 2/18/2003
Citation: RADOMSKI, A.A., FREEMAN, D.W. THE IMPORTANCE OF MONITORING DOUBLE-CRESTED CORMORANTS PHALACROCORAX AURITUS WITHIN AQUACULTURE PRODUCTION AREAS.. AQUACULTURE AMERICA CONFERENCE. 2003. p.243.

Interpretive Summary:

Technical Abstract: Increasing numbers of double-crested cormorants (Phalacrocorax auritus) at commercial fishponds have resulted in biological, economical, and social conflicts. Aerial surveys by fixed-wing aircraft were conducted to monitor the wintering cormorant numbers from 1999-2002. Observations were conducted during the last 3 hours of sunlight and encompassed catfish production areas. 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. Cormorant numbers peaked (>26,000) in early February 2001 and a total of 12 to 15 night roost sites were monitored during 1999-2002 (Table 1). 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.