Double-crested Cormorant Movements in Relation to Aquaculture in Eastern Mississippi and Western Alabama

Authors

Brian Dorr, U.S. Department of Agriculture, Animal and Plant Health Inspection Service Wildlife Services, National Wildlife Research CenterFollow
D. Tommy King, USDA/APHIS/WS National Wildlife Research CenterFollow
Mark E. Tobin, U.S. Department of Agriculture, Animal and Plant Health Inspection Service Wildlife Services, National Wildlife Research Center, U.S. Department of Agriculture, Animal and Plant Health Inspection Service
J. Brent Harrel, U.S. Department of Agriculture, Animal and Plant Health Inspection Service Wildlife Services, National Wildlife Research Center
Patrick L. Smith, U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services Alabama Fish Farming Center, U.S. Dept. of Agriculture, Animal and Plant Health Inspection Service Wildlife Services

Date of this Version

7-17-2004

Comments

Published in Waterbirds 27:2 (2004): pp. 147-154.

Abstract

Concomitant with increasing numbers of the Double-crested Cormorant ( Phalacrocorax auritus ), catfish producers in eastern Mississippi and western Alabama have reported damage caused by cormorant predation. VHF telemetry was used to document movements of 25 cormorants from all known night roosts in the aquaculture producing areas of eastern Mississippi and western Alabama, January-April 1998. A total of 193 day locations and 396 night roost locations of the cormorants were obtained. Each cormorant was found in the study area for 57 ± 4 (SE) days. Each cormorant averaged three night roosts (range: 1-8) and spent 20 (±2) days at each night roost site. Over 95% of cormorant day locations were within 19 km of their night roosts. Catfish pond use by cormorants varied between roost sites. Cormorants from five of eleven night roosts had ≥ 30% of subsequent daytime locations on catfish ponds and birds from five of the six remaining night roosts did not visit catfish ponds on the following day. Foraging distance and frequency of night roost interchange was less for birds in this study than those reported from other aquaculture regions. We suggest roost harassment efforts should be focused on specific roost sites and some roost sites should serve as unharrassed refugia from which cormorants are less likely to cause damage to aquaculture.