In Florida we have a fish called a SNOOK, my favorite fish to catch and eat, next FLOUNDER, followed by BLACKTIP SHARK.
As others have mentioned it's all about how the fish is handled from the time of catch to the dinner table. I usually cook all of my fish on a grill; and hardly ever will freeze a fish, I like my fish fresh out of the water.
When I catch a small blacktip shark that I want to keep for dinner, I immediately clean the fish (cut off head, pectoral fins, dorsal fin, and remove the guts) and put it on ice. When I get home I cut the carcass up into steaks about 2" thick, put the steaks in a container filled with ice and water, and add one ounce of lemon juice for every pound of meat, I soak the meat overnight. When I'm ready to grill the shark steaks I rinse the meat and let the steaks dry. Fire up the grill and throw the steaks (with the sharkskin on) and cook them for a short time until the meat turns white. When the sharkskin is easy to pull off of the meat, the steaks are done and ready to eat. What is nice about shark is that they only have a vertebrate, no tiny rib bone to worry about.