I had a somewhat similar experience wade fishing in a newly formed man-made harbor next to a patchy reef when GF and I were in the southern Yucatan, MX in 2007, south of Puerto Aventuras.
A big Cubera Snapper hammered a scented rubber jig I was bouncing along and was on. All of a sudden, it changed fighting style and came up to the surface zig-zagging, which is unusual for a big Cubera in the Northern Hemisphere, to say the least. I could see a wake behind it, then the line stopped screaming and I reeled in a big Cubera head.
When I realized exactly what had just happened, I climbed up out of the water on the jetty and gave the big head to the locals fishing in the adjacent canal. I didn't figure it was a good idea to stay standing chest deep in a blood trail leading directly back to, wait for it, ... me.
When I was finally ready to drag my gear up and leave, an Italian guy living local comes up and asks me if it's OK to spearfish where I had been fishing. I said "Sure, but watch out for the toothies". He says, "Don't worry, they always leave around the same time every day." That's what you call local knowledge.
