Idaho Fish and Game will be electrofishing on two stretches of the Henry's Fork over the next two weeks. They will be electrofishing the Vernon-to-Chester stretch on May 6, 7, and 14, and Box Canyon on May 11, 12, and 18. All dates are pretty firm barring any unforeseen equipment issues or weather conditions (e.g. lightning).
Regional Fisheries Biologist
Idaho Department of Fish and Game