ARY Incorporated makes this great cut resistant glove. If you are one who filet's your fish on your boat before you get back to port, a cut glove is a no brainer for you. With all the rocking and rolling on the ocean, serious cuts are more likely at sea then at home. Plus if you injure yourself badly at sea, the time it takes help to get to you is a gamble I know I don't want to take. Not when wearing a cut glove could have prevented the injury.
Cut gloves are one of those things that pays dividends once you realize it saved your hand from a deep gash. You will only need one cut glove to protect the hand that isn't holding the knife. Would it hurt to have one on each hand? No, as wet knives have a tendency of slipping and sliding and a cut on your main hand is not a miraculous occurrence. Please consider at least putting one on your off hand, the hand the holds and steadies your catch while you fillet it.
These cut gloves are reinforced stainless steel strands that give level 4 cut protection. These are great protection from spectra line and you could fish with these gloves to protect your hand from the spectra ripping through them. They have D3 technology for comfort and they aren't terribly uncomfortable, not nearly as much a discomfort as a large deep cut would be. Now these gloves aren't made to be tested by taking the end of your knife and piercing it through and they don't recommend using a serrated knife either. The anglers I know don't tempt fate and don't take unnecessary chances with knives, just use it properly and it will protect your hand from a stray knife that would otherwise cut you.