U.S. Department of Agriculture: Animal and Plant Health Inspection Service
Date of this Version
January 2005
Abstract
WP rnnrlurted fnraging ob,ervations, food habits studie~, and producer aurveys to determine the foraging behavior and monetary impact of great blue herons Ardca hr.rodia5, great egrets A. alba, and little blue heron5 E m t r a cnurulua lora-g in-e at Arkansas haiffish farms. Although great egrets captured most baitfishlminute, captureslstrike were nearlj identical among the three wadine bird snecies. American eizzard shad Dorosoma crordinnum. eoldfish Carossius nuratul. D - . - and giant water bugs Hemiplera: Beloston~atidaew ere collected from the gastro-intestinal tract of grent blue herons. Only golden shiners ,Votrrni~onuc,~ry soleucur and goldfish were found in great egrets. We found dragonflies Odonaro, golden shiners, green sunfish Lepomis cyancllus, and water bugs in little blue herons. In contrast to other birds collected, snowy egrets E. thula were found to contain mosquito fish Gornburiu ujfinb. Among 2,742 teleost otoliths recovered from collected great blue herons. great egrets, and little blue herons, most otoliths belonged to the Cyprinidae family (including the baiffishes). Surveyed farm managers use various auditory 2nd visual stinluli to disperse fish-eating birds from their farms. Surveyed baitfish farnlers suggested that the average cost of their annual bird harassment program was $11,580 at relatively small farm> (< 202 ha) and $104,560 at relatively lar.ce (-2 202 ha) baiffish aquaculture facilities. &? estimated the replacemeut cost of baitfish consumed by wading birds based upon their daily food requiren~ents, the food habits of herons and e-er ets at baiffish farms. the h,v.o otheticnl abundance of wadin-e birds at a particular baiffish farm (relative to surrey results), the duration of herons and egrets reported by farm managers, and current baiffish market values.