Steven G. Hall and Randy R. Price
Predatory birds cause problems for aquaculture farmers because they eat their crops. In Louisiana, birds such as cormorants and pelicans prey on young catfish and crawfish, which costs producers thousands of dollars each year in lost revenue. The LSU AgCenter Aquaculture Research Station has lost not only fish because of bird predation, but also the valuable research associated with them.
To reduce loss, aquaculture farmers may spend up to as much as $100,000 a year on bird abatement programs. One of the most common approaches to scare birds from ponds is the use of sonic cannons. They work well initially, but the birds become accustomed to the loud noises, and the cannons can be bothersome to surrounding communities.
Poisons, scarecrows and nets also are used. Poisons work well but may kill other species as well as the troublesome birds. Scarecrows may work for short periods, but just as with the cannons, the birds become used to them. Nets are costly and difficult to mount on ponds larger than five acres.
An alternate approach being developed at the LSU AgCenter and tested at the Aquaculture Research Center is a small, self-guided boat – a “scarebot.” These robotic boats, which resemble miniature houseboats, are solar-powered and have top speeds ranging from 5 to 7 miles per hour. One model of the boats is equipped with an infrared sensor to detect motion, which in turn triggers a water cannon that annoys and drives away the birds.
Propelled by paddle wheels, the boats have shore sensors that keep them from running aground. The sensors close a magnetic switch when the boat touches shore and guide the boat to turn back into the pond.
LSU AgCenter researchers are studying use of a portable GPS (global positioning system) to maintain the boats within a predefined area, such as part or all of a pond or reservoir. Some of the boats have operated for weeks with minimal human intervention.
Advantages of using robotic boats include reduced human input, fewer errors and lower costs than other abatement programs. Challenges include maintaining power, control and self-sufficiency, as well as potential safety and maintenance concerns.
Robotic boats are highly effective at reducing bird predation on selected aquaculture ponds (Table 1). Besides the possibility of helping the aquaculture industry, the robotic boats have the potential for many other environmental management applications such as measuring water quality. Research is continuing.
To test the effectiveness of the boats, the U.S. Department of Agriculture is interested in comparing the robotic boats with other methods such as netting over ponds and propane sonic cannons. The study is set to begin in the spring of 2003.
Steven G. Hall and Randy R. Price, Assistant Professors, Department of Biological and Agricultural Engineering, LSU AgCenter, Baton Rouge, La.
(This article was published in the winter 2003 issue of Louisiana Agriculture.)