 | ||||||||||||||||
  |
| |||||||||||||||
FAQs: Piranha and rotenone - Lakewood Townhomes Pond Renovation Project | |||
Updated Nov. 17, 2009 Contact: Gabriella Ferraro, 772-215-9459; or Background: On Oct. 13, a resident caught a red-bellied piranha while fishing in the Lakewood Townhomes retention pond near West Palm Beach. FWC fisheries biologists sampled the pond immediately and found no more piranha. However, the FWC continued sampling this pond, and 10 days later, biologists captured another piranha. Because of the possibility of even more piranha, and the chance that this species might reproduce, the FWC decided to apply a fish toxicant, rotenone, to the pond to make sure no piranha survive. This action is a standard fish management technique.
What are piranha?Piranha are attractive, relatively small, and somewhat mysterious fishes from South America. There are many species, but the species collected from the Lakewood Townhomes' pond is the red-bellied piranha from Brazil. Piranha have sharp teeth, can take neat bites, and are potentially dangerous even to man, though their ferociousness is often greatly exaggerated. FWC regulations prohibit the owning of any species of piranha. How did piranha get in the pond?Someone may have moved to Florida with piranha that were legal in their former state; when they realized these fish are prohibited in Florida, they may have released them in the pond, which is also illegal. It also is possible that a Florida resident acquired piranha illegally, and released them when they were moving or to avoid legal trouble. What if someone I know has piranha?Have them contact the local FWC regional office. Under Florida's Pet Amnesty program, they can voluntarily surrender their piranha to the FWC with no questions asked and no penalties. What is rotenone?Rotenone is a substance from roots of tropical plants in the bean family. It has been used as a fisheries management tool since 1934 and is very effective in eradicating unwanted fish without harming habitat. It works and breaks down quickly, leaving no harmful residue. The Environmental Protection Agency closely monitors rotenone, its use and effects. Is rotenone safe for people and animals (livestock)?The EPA conducted an intense, 10-year study and concluded that, if used according to label instructions, rotenone does not pose a risk to humans or the environment. Is there danger in drinking rotenone-treated water?As a precaution, the FWC advises against it. However a 160-pound person would have to drink more than 23,000 gallons of water at one time to receive any effects. How does rotenone work?Rotenone stops fish from using oxygen absorbed in the blood. It affects fish and some amphibians and aquatic invertebrates. Fish are highly susceptible because rotenone is readily absorbed through their gills, and they cannot escape exposure to it. Is rotenone a selective pesticide?Although rotenone has some toxicity to all oxygen-breathing animals at very high dosages, it is selective to fish at the concentrations used by fishery biologists. In general, most common aquatic invertebrates are less sensitive than fish to rotenone, but some of the zooplankton are equally sensitive. Snails and clams are quite tolerant. May people eat fish killed by rotenone?No. The EPA has not established such guidelines. What happens to rotenone after it has been applied?Rotenone is an unstable compound that breaks down when exposed to light, heat, oxygen and alkaline water. The breakdown process is very rapid. Scientists have been able to identify about 20 degradation products, most of which spontaneously break down to lesser, nontoxic substances. Ultimately, rotenone breaks down into carbon dioxide and water; two common substances. How long does it last?How fast rotenone breaks down is affected by temperature, light, oxygen and alkalinity. Generally, most treatments are made during summer months. At 80 degrees Fahrenheit, treated water will detoxify naturally in less than four days. Generally, most lakes treated with rotenone completely detoxify within five weeks of treatment. In natural waters, other factors that influence the degradation rate and therefore reduce the toxic effect include the presence of organic debris, turbidity, lake shape and depth, dilution by inlets and runoff and the dosage used. Is rotenone likely to enter ground water and pollute water supplies?The mobility of rotenone in soil is low to slight. The expected leaching distance of rotenone in soils would be less than one inch in most types of soils. An exception would be in sandy soils, where the expected leaching distance is about slightly more than three inches. Rotenone will bind to organic matter in soil, so it is unlikely that it would enter ground water, even if it had not degraded. Because of its rapid breakdown, rotenone leaves only temporary residues that would not persist as pollutants of ground water supplies. How long is rotenone effective?Its effectiveness is based on temperature. Studies in Arkansas showed it breaks down in 72-96 hours. It breaks down quickly when exposed to light, heat, oxygen and alkaline water. What other uses are there for rotenone?Rotenone is used as a garden insecticide to control chewing insects, has been used as a dust on cattle, and is used as a dog and sheep dip, in addition to its use as a fish-control agent. The FWC recommends against using water recently treated with rotenone to irrigate crops (water may be used 96 hours after treatment). How thoroughly was rotenone studied before the EPA reached its conclusion that it does not cause cancer?Rotenone was fed daily to rats, mice and dogs in studies that ranged from six months to two years. In two studies, high levels were fed daily through three generations with no evidence of significant adverse effects. No tumor induction was observed, even when 75 ppm were fed daily to rats or when 1,200 ppm were fed to mice. In the tests with both males and females of each species, there was no firm evidence that rotenone caused any increase in the incidence of tumors. In some lots, treated animals had significantly fewer tumors than untreated groups. | |||
| |||
Our mission: Managing fish and wildlife resources for their long-term well-being and the benefit of people.
|
|
