You will eventually come across ferocious mosquitoes, no-see-ums, black flies, or other biting insects while fishing in rivers, streams, lakes, or the ocean.
To avoid mosquito bites, follow a few basic principles.
Wear light pants or waders, a long-sleeved shirt, a wide-brimmed hat, and/or a hood even in hot weather. Consider wearing a neckerchief under your hat to cover as much skin as possible around your neck and ears. This also shields your skin from UV rays emitted by both direct sunshine and light reflected off water.
Because topography influences wind, one location may be dead calm while another not far away has a lovely breeze to keep the bugs at bay. You can harness the strength of the wind (or even a light breeze) at places such as a valley or canyon bend, a point of land protruding into a lake or sea, or by taking a boat out on the water.
Obtain a spray. Repellent can be sprayed straight onto garments, but make sure to read the label first. More information can be found
here. If you are on land, the spray frequently kills the mosquitos with which it comes into contact and then dries, leaving a repellent residue on the leaves and trees.
Mosquitoes breed in standing water, so lake fishers may not be able to avoid them, but if you're fishing in a river or stream, look for an area where the water is moving quickly (but where the river still has pools where fish might congregate). That's normally when the terrain gets a bit steeper, and it's also where you'll get a little more wind.