If you were a fisherman you would know…
that fluorescent green is the most visible color. I don’t know if you can get a kayak in that color (or would want one!) but you would be seen. Notice how many communities are changing their road signs to fluoro green.
Other considerations-
Dark colored kayaks are HOT, meaning you could fry an egg on the deck out in the bright sun. In the southern regions, this would be of concern to me. On the other hand, white, eggshell, and other light colors are hard on the eyes when paddling in the bright sun.
Dark colors also show scratches and other damage much more noticeably. White is the easiest color to make an invisible repair on.
butterflys
Speaking of Butterflys! We were crossing the Potomac River 30 miles s of DC late last summer during the migration south of the Monarch. We saw hundreds and hundreds of these things fighting a southerly breeze so hard they were going sideways! It was really awesome to see them on their journey home…
Bumblebees too
I’ve also seen bees atracted to bright blue, I believe it’s because it reflects a lot of UV light. For visibility to power boaters I’m told I’m a lot more visible when I put up my red and yellow sail