Let me clarify because I think you read me wrong due to my lack of info given...I have only ever USED shears underwater and I carry a knife as well. I would cut myself free with shears to answer your question about the hook. I wouldn't use a knife for sure.:11doh: My comment was directed specifically towards the use and need for a knife and not shears. I didn't make that very clear in my post.

The knife, as I said, is only used for fruit and I doubt if I will ever need to use it for anything else.
I also dive a spot with tons of fishing line and fishing activity from shore. I have NEVER been hooked by a fishermen yet in 5 years. The viz is rarely better than 5 feet. Call it luck if you will...maybe my number is up...
My point is that I can't imagine a situation where I would need a knife to save my life in a recreational diving scenario. If I need a knife to save me say in Bonaire while diving a reef, then I am an idiot and it's not a knife I truly need...it's brains. (that was my point)