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Title: The white amur as a biological control agent of aquatic weeds in the Panama Canal
Authors: Panama Canal Company.
Aquatic Plant Control Research Program (U.S.)
Custer, Phillip E.
Halverson, Francis D.
Malone, James M.
Von Chong, Cesar.
Theriot, Russell F.
Keywords: Aquatic plant control
Hydrilla verticillata
Aquatic weeds
Panama Canal
Weed control
Gatun Lake
White amur
Grass carp
Ctenopharyngodon idella
Biological control
Issue Date: Apr-1979
Publisher: Environmental Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Miscellaneous Paper
Abstract: The Panama Canal has been plagued with both floating and submerged aquatic weeds since its opening. Although more and more money has been spent on herbicides over the years, the weed problem has increased. In February 1978, the Panama Canal Company introduced the white amur fish, Ctenopharyngodon idella (Val.), as a biological tool to control the submerged macrophyte, hydrilla, to Gatun Lake, the large freshwater reservoir through which the majority of the length of the Canal passes. Ninety percent of the first shipment of fish (125,000) were estimated to have died due to the rapid change from cold Arkansas water temperatures to the warm tropical waters of Gatun Lake. A series of tests was conducted to determine tempering rates of the fish with temperature, dissolved oxygen level, and time as the variables. Various experiments with chemical additives in the tempering water such as salt and quinaldine were also conducted. Based upon the tests, a tempering facility to acclimate a second fish shipment was constructed which circulated chilled lake water through a large fish holding tank for a period of 2 days during which time the temperature was gradually elevated and salt and antibiotics were added to the water. After tempering, the fish were successfully stocked in isolated arms of the, lake using a helicopter for transportation. A third shipment of fish (177,000) was delivered in August 1978 to replace fish lost from the first shipment. Fish were tranquilized with quinaldine prior to shipment from Arkansas. Dissolved oxygen was regulated in flight to approximately that of the lake. Fish were released directly into the grow-out areas resulting in less than 1 percent mortality. Fish from the first two shipments were released from the grow-out areas into Gatun Lake in August 1978 after attaining an average weight of 1 kg. The Panama Canal Company plans to monitor the effect of the fish on the hydrilla infestation with annual infrared aerial photography and to initiate an annual white amur stocking program in FY 1981.
Appears in Collections:Miscellaneous Paper

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