[Craigbob]

Another option to enhance the fishing line in the image is to use an adjust brush and paint over the line as carefully as possible (may have to use small segments if it's curved) and just increase Exposure/contrast/etc... on the line alone and not the rest of the image. Kind of the reverse of the process used to get rid of phone/power lines in pictures.

Worth a try.

[35mmfilmfan]

Ee, when I were but a lad, I knew a couple of guys who used matches instead of floats, held to the line with a slip knot, with no weights on the line at all, just letting the bait (gentles or sweetcorn) slowly sink naturally through the water. This was river fishing, and they certainly seemed successful - although, since the river was the Thames in the late 1950s, nothing they caught was edible !

[RichardJ]

You could try and adjustment brush just to increase the contrast where the line is, or try reducing the brightness of the water which may make the line more visible.

Incidentally, I think he is actually feeding the fishing line though a piece of metal tubing, rather than tying it to the end of a match. I think it is a technique used to make the fishing line lie flush to the bottom of the river/lake so as to catch bottom feeding fish such as carp.