I don't know how true it is but I was told that WD40 is made with shark oil and that is why WD40 is used as a fish attractant. I have used it in the past but can't really say if it made any difference. I was also told that if you rub WD40 into your skin where you have arthritis that it will help to reduce the pain.
The official WD40 web site list the following uses for fishing but it doesn't say it helps to catch fish....lol.
http://www.wd40.com/uses-tips/category/sports-and-recreation/
Keeps top line guides from freezing on fishing rods when ice fishing
Polishes fishing lures
Drives moisture from fishing tackle
Drives moisture from fishing waders after use
Keeps fishing lures corrosion free
Keeps fishing reels rust-free
Keeps plastic fishing lures from sticking together
Keeps tackle from freezing during ice fishing
Lubricates fishing reel knobs
Lubricates swivels on fishing lures
Prevents fishing flies from rusting
Refurbishes antique fishing lures
Removes paint from fishing lures
Protects ice-fishing auger from rust
Rejuvenates soft plastic fishing lures
Spray on fishing line to keep line from becoming stiff