My take on Fishing & diving/Scruba blades is a high chromium steel, 440 series, I’ve made & used. I sharpen every dive or three. If I can cut net & fishing line to clear...Tap on my tank with the spine. I can dispatch any fish or make my issues know with any Shark that I’m not easy eats. It’s fine by me!.... I’ve found most don’t wash their gear with fresh water well, if at all.. so?? Stay safe & have fun!