When casting jigs and lures and using hi vimono.
They likely are, under the circumstances of clear water and heavy angling pressure. But, at the same time, it could very well be that they're "spooked" as much or more by movement, shadows, noise, or other factors presented by the angler or their boat.
It may also depend on the mood of the fish, since actively feeding fish or spawning fish in shallow water may be oblivious to or unconcerned about line size or color ... but, fish in a neutral or negative mood, even in stained or deeper water, may refuse even the most tempting offers.
The one point of consensus from previous discussions on this subject, says that hi-vis line is a visual aid to the angler that has trouble seeing lo-vis or clear lines, which allows the angler to detect the bite more often ... leading to more opportunities to set the hook on a fish.
The trade-off is the potential to not get as many strikes, due to the possibility of the fish being "line shy"... versus ... the potential of missing those strikes that do occur, due to the angler not being able to see the line movement that indicates a biting fish.
Personally speaking ... I don't believe the fish are smart enough or have the capacity for long term memory, nor have the capacity to pass on or retain learned negative events. If they were capable of such things, the color of the line would be the least important factor. The fish ARE capable of seeing most any line we use, so they're also obviously capable of seeing the HOOK embedded in the live or artificial offering being presented. If they could perceive a "threat" from the line, color of the line, or the presence of a hook ... we wouldn't be catching too many of them, in the first place.
... cp
Here's a thought. Elwood "Buck" Perry (circa 1970) - the "father of structure fishing" (and spoonplugging) - advocated against worrying about line color. His reasoning was that he wanted the fish to know "where" it's next meal was coming from! He only considered line choice by depth & speed control (line test and diameter).
However, in this modern era, our older fishermen's eyes do benefit from hi-vis line colorations. Consequently, a good compromise would be to use the highly visible line as your main line and attach a 3' - 4' flurocarbon leader, for abrasion resistance and less visibility. Best of both worlds!
"A voyage in search of knowledge need never abandon the spirit of adventure."
Well, I do all the "wrong" things and still catch fish.
Member BS Pro-Staff and Billbob Pro-Staff
Proud Member of Team Geezer... authorized by: billbob and "G"
X2
I use high vis braid and mono and both catch me limits! I agree that if the water is VERY clear then you may want a more invisible line but I have never seen or fished clear water like that except in the gulf.
USAF Retired and fishing!
We use hi vis yellow suffix elite all the time with good results.