While fishing for trout at night in urban areas, I have frequently seen trout feeding in the glow of a riverside light. Now, I do not know why the trout choice to feed there, I can only speculate that they are attracted to the insects which swarm around such lights. They might also choice to feed there simply because they can see drifting prey easier.
How to catch these trout?
Seeing them is the easy part, getting them to feed has always been much challenging. First, and foremost. Stealth is important, I advise to cast into the glow of the street light before taking a look. Trout are more confident at night, but they will still dart away at the first sign of danger.
How I target these fish does depend on what tackle I am using. When fly fishing over the summer months, I prefer to use a large dark dry fly. Which I will cast upstream and allow to drift back down. It is also possible to fish a dry fly behind a bobber in the same fashion. When the water is colder, and the trout unlikely to raise I will strip a dark streamer pattern instead.
If I am spinning, then I like to cast upstream of the illuminated area, and slow retrieve lures through it. I like to use a floating Rapala, and retrieve it ever so slowly.
Are trout feeding beneath lights easy to catch?
No, they are easy to locate, but I personally find them more challenging to hook than fish feeding in darker parts of the river. I suspect they might already be on edge due to feeding in such a bright area.
I also notice that the trout which do feed in such areas are generally smaller than average in size. I personally make a few casts, then continue fishing up the river.