Tolerance of lumpfish,Cyclopterus lumpus,to freshwater bath treatment for amoebic gill disease,Neoparamoeba perurans,infection and efficacy of different treatment regimens |
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| Authors: | Jim Treasurer Tom Turnbull |
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| Abstract: | The tolerance of lumpfish to freshwater treatment and efficacy over a range of salinities and treatment durations is examined. No structural and cellular changes were noted in organs, including gills and gut, sampled 48 hr posttreatment because of freshwater baths for periods of up to 5 hr exposure at 0 ppt or continuous treatment in 15 ppt water for 10 days. Behavioral indicators such as activity and ventilation frequency were also not significantly different between treatments, with the exception of the first trial where lumpfish were inactive during treatment in 0 ppt water compared with active fish in 32 ppt seawater. Amoeba numbers declined from an initial 21.5/gill arch to 0.33 after 3 hr in freshwater and to zero after 5 hr, and to five amoebas/gill arch after 3 hr in brackish water treatment (15 ppt). When fish were treated continuously for 15 days in 15 ppt water, amoeba numbers declined from 231 to 3.7/gill arch after 3 days and a mean of 1.75 amoebae after 10 days. In the last trial, no amoebas were present per gill arch after 3 hr treatment in 0 and 3 ppt bath. |
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| Keywords: | amoebic gill disease Cyclopterus lumpus freshwater treatment lumpfish Neoparamoeba perurans salmon cleaner fish |
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