I do it proactively, then we stay inside as much as possible until after dark.

Biting flies can be even more annoying, even miles offshore. This winter I'm going to do a project to add mosquito nets around my bimini so the cockpit is protected from flies. I'm thinking about a net for the opening dodger window, along with side and aft nets from the bimini. The sides and back could be weighted with lead beads sewn into the border.