3/8/2006
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Parasite Infests Lake Ouachita Fishery |
 HOT
SPRINGS –There’s a new bug in town that Lake Ouachita anglers should be
aware of this year. A copepod parasite has infested Lake Ouachita. For
those wondering just what a copepod is, they are very small marine and
freshwater crustaceans of the subclass Copepoda. They have an elongated
body and a forked tail.Over the past three years, one particular freshwater copepod has infested fisheries in Virginia, North Carolina, Tennessee and Texas. The parasites are most commonly found on striped bass in these fisheries, but where the infestation is high, they can also be found on largemouth bass and walleye. According to Arkansas Game and Fish Commission biologist Brett Hobbs, who recently conducted gill-netting samples on the South Fork of Lake Ouachita near Mt. Ida, biologists observed the parasitic copepods, Actheres, in the mouth and gill raker area of striped bass. "All stripers in the netting sample did have some of the parasites. Thus far we classify the infestation as light to moderate although it may get worse before it gets better," Hobbs said. Tennessee Wildlife Resources Agency reports several species of parasitic copepods can inflict great harm and even kill fish, but Actheres is not considered to be one of them. Virginia Department of Game and Inland Fisheries reported Actheres contributed to a striped bass die-off in Smith Mountain Lake. They reported the stripers were in poor shape due to reduced shad forage in the lake and large stripers collected from the die-off had high numbers of Actheres, Hobbs explained.  "This
parasitic copepod is visible as the adult stage in the mouth of the host
fish. The adult stage is about 2 to 3 millimeters long and creamy to
white-yellow colored. For you anglers out there, they are shaped like an
Uncle Josh pork frog (body with split tail)," Hobbs stated. "The tail
portion of the copepod is actually egg sacs which will distribute into
the water and hatch into a larval free-swimming form which will infect
other fish," he added.A leading researcher, Dr. Thomas Shahady from Lynchburg College in Virginia, has ongoing research which is testing the effect of this parasite on the respiration of the host fish. Early study results indicate the parasites increase respiration rate which could be most problematic during low dissolved oxygen periods, Hobbs said. "The bad news is this parasite persists in affected lakes for at least several years after infestation, but typically in lower numbers. We will have to wait for further research findings to determine how harmful this parasite will be to our fisheries," Hobbs said. In the mean time, anglers should not move fish from one water body to another to avoid contamination. Also, livewells should be drained to avoid moving the larval form. |
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