What are wind lanes?
Wind lanes, scum lanes, foam lines and slicks are distinctive parallel lines of bubbles that form on the water surface during windier weather. They often cause flat areas, or slicks, to develop between more rippled water on either side. They're one of the most productive places to target when trout fishing on reservoirs, lakes and lochs. If you seek them out and fish along them, you'll increase your chances of catching.
What creates these scum lanes?
Scum lanes or wind lanes form due to an underwater procress called Langmuir circulation in which a series of slow, counter-rotating underwater vortices called Langmuir spirals align with the wind at the water's surface and rotate in different directions. The visible part of the scum lane is actually formed by tiny air bubbles and plankton stuck in areas of downwelling.
Why do they hold trout?
The underwater Langmuir circulation creates upwellings and downwellings which cause phytoplankton and zooplankton to become more concentrated within the slick. Dapnia, in particular, have been shown to be more concentrated within wind lanes than outside them. As a result of the higher food density, predators including trout and coarse fish will move into the wind lanes to feed. As they affect surface tension, flies and other invertebrates can accumulate at the surface, so you may often see fishing rising along the lanes.
When do scum lanes form?
Experts reckon specific combinations of wind and wave action are required for their formation. As the name suggests, these wind lanes only form on windier days. Winds of 7mph or more are usually required to trigger their creation and they usually break up when winds top 15mph. They always form in parallel to prevailing wind.
What flies should I use in wind lanes?
Many fly fishers think you should only fish dries in wind lanes. However, although the wind lane appears to be confined to the surface, the underwater vortices within the wind lane will mean that there's a whole load of plankton, inverts and small fry feeding far beneath the surface all along the wind lane. It's certainly worth trying dries when conditions are right, but subsurface flies are often even more effective.
How can I locate wind lanes?
Take your boat to the side of the lake that's closest to the prevailing wind and motor up the lake until you spot a lane. The parallel lines of bubbles and slack water are usually visible from a good distance, but you might also see birds and fish rising. Headlands and areas that disturb the wind as it's blown onto the lake seem to aid their creation.
How do you fish wind lanes?
Not all wind lanes hold fish, but it's worth fishing them whenever you see them as underwater food is likely to be more abundant. Line your boat up with the wind lane so it's parallel with the middle - you can use your reverse gear to position yourself precisely - then deploy your drogue.
By setting up your drogue so it can be easily adjusted from the middle you can control the direction of your drift to keep your boat within the wind lane. When you reach the end, start the engine steer widely around the lane so you don't disturb the fish and then return to the start and do it again, or try another wind lane.