i'm planning to buy a new pair of sunglasses but i'm not sure what I should buy. i'm narrowed it down to Ray-Ban, Oakley, or Costa Del Mar….which should I get??…btw, I fish quite a bit out in the gulf of mexico, so i think i definitely need blue mirror lenses.

I hate Oakley, they are no longer allowed in my store. I had a patients pair break and I was told that they were designed to break like that and no one would help me (I did warn you ,Oakley, that I would tell anyone who would listen and never buy your products again!). I was mortified for my whole industry by their idea of customer service.
Are you getting prescription in them or just over the counter? Raybans look cool, but don't have the quality that they once did (although at least they will replace them if the break in the first year).
Costa Del Mar- I haven't worked with theses, so no advice there.
Have you checked out Maui Jim and Persols. I own both (plus a pair of Versace and Kate Spades, but those are fashion sun wear, I did polarize them though). I think my persols are my favorite, polarized glass lenses, optically, they are fantastic and the frame is well made and extremely durable. If your going to spend the money on good sunglasses, make sure they last you several years.