Bonefish have an extremely good sense of smell. It is this sense of smell that allows them to consistently feed on the flats. Although we witness bonefish feeding throughout the water column by watching them charge a stripped shrimp or baitfish fly, a large part of their diet is comprised of prey that live within the sandy bottom such as clams, worms, crabs and so on. In order to find these organisms within the sand, bonefish actually use their sense of smell to sniff them out before blowing a hole into the sand to reveal them!
If you have fished for bonefish before, you are most likely aware of their amazing sense of smell. Just a touch of suncreen from your hand that found its way onto your fly can cause a refusal from even the most eager bonefish. Any foreign scent on your fly could easily cause the same reaction, not just suncreen!
The next time you decide to tie up some bonefish flies, consider not using any head cement or glue to finish the fly. Head cement could leave a foreign scent in the water, especially if tied up the night before. A clean whip finish is more than durable enough anyhow, especially if performed a few times. Even without head cement, the head of the fly will most likely outlast the life of the hook. Stainless hooks still have a short lifespan when fished hard in saltwater and should not be fished for extended amounts of time anyhow (unless properly rinsed off after each use).
Can bonefish smell the head cement on our flies? We’re not sure. Unfortunately we don’t speak ‘fish,’ otherwise we’d ask. However, by not using head cement we’re allowed a little more peace of mind before making the shot.
Honestly I do not use head cement or epoxy on any of my flies. If you catch one or two fish on the fly it will most likely be garbaged anyway. Most saltwater fish have teeth or rough mouths and if you fight them for a few minutes they will be pretty roughed up. Bonefish have pretty rubbery mouths but get a fly back in the crushers and it will be done anyway.
A research group in the Bahamas, the Eluthra Institute, I believe did a study with sunscreen coated on their shrimp food. Captive bonefish did not seem to refuse the tainted food. When I tie on a new fly I grab some mud and rub it into the fly and then rinse it off. Takes care of any scent business.