No abstract

No abstract

No abstract

No abstract

Salmincola spp. infestations can adversely affect freshwaterreared salmonids. Control methods tested to date have had limited success; consequently, we conducted a pilot field trial to evaluate SLICE (0.2% emamectin benzoate [EB])-medicated feed to reduce a natural infestation of S. californiensis in freshwater-reared rainbow trout Oncorhynchus mykiss. Before the trial started, 96 of 1,500 rainbow trout broodstock held in a flow-through raceway were impartially captured, sedated, uniquely tagged, and returned to the raceway. Pretreatment S. californiensis infestation prevalence and intensity were 97% and 10.4 ± 7.6 (mean ± SD) adult female parasites per fish, respectively. Treatment was administered at 50 µg EB·kg fish −1 ·d −1 for 7 d. By the end of the trial (43 d posttreatment), infestation prevalence and intensity had decreased to 32% and 1.6 ± 1.1 adult female parasites per fish, respectively. These results suggest that SLICE-medicated feed can be used to reduce natural infestations of S. californiensis in freshwater-reared rainbow trout.