Tuna (tough scale: 10)
Bigeye, dogtooth, longtail, even the blackfin and little tunny are no-quit fighters, but it’s the top-tier yellowfin and king-of-them-all bluefin tuna that can, quite literally, break your heart. One look at the torpedo-headed, quick-tapering body or the lunate, always-beating tail, and you understand why they’re among the planet’s fastest-swimming creatures.
Hooking up with a tuna is like being connected to a runaway semi—one that makes depth-bomb plummets. All you can do is ready your whole body for the job of cranking and lifting without a second’s rest. I’ve seen NFL linemen quit mid-fight. Anglers who battle giant bluefin often end up with back problems. Fish in the 300- to 1,000-pound range (the record is 1,496) call for 80- to 130-pound tackle. Truly, these warm-blooded creatures are the raging bulls of the sea.