There aren’t many fish I haven’t caught, so I get asked this question a lot: Pound for pound, which fish is the strongest? I wish I had a concrete answer.

The standard comparison is to tie two fish tail to tail and see which one wins, but that’s not really feasible, and there’s more to strength than just pulling. There’s a difference between inshore, where a giant trevally probably is king, and offshore. Is a 50-pound giant trevally stronger than a 50-pound bonefish (if bones got that big)? Is a 1,000-pound bluefin tuna stronger than a 1,000-pound blue marlin? Which would be harder to catch on identical tackle from, say, a stationary boat? These are good questions.

In an effort to save time, I’ll limit my semi­random thoughts to offshore species, which I can quickly narrow down to a blue marlin and a big yellowfin or bluefin tuna. I would jump at the chance to catch a 300-pound blue marlin, but you couldn’t pay me enough to fight a 300-pound tuna. I know guys who have fought those critters for five or six hours on 50-pound tackle, and boat handling makes little difference because all they do is dive deep and swim away. If the criterion is just pulling, a big tuna wins.

On the other hand, I’ve caught 300-pound blue marlin on a fly rod with an IGFA 20-pound tippet, which took two and a half hours, even with the superb boat handling of Capt. Chris Sheeder. There’s no way I could have caught a 300-pound yellowfin on fly tackle … ever!

Blue marlin are sheer pent-up violence. The strike is spectacular. Their first run is more than a quarter-mile of greyhounding, after which they sound. When you eventually work them back to the surface, the jumps begin again. Granted, a good captain can back down on a blue marlin and score a technical “release” by getting the leader into the rod tip, which means you were within 30 feet of the marlin. However, bringing the fish alongside is an entirely different matter, especially on a fly rod.

I more or less answered the pound-for-pound question while writing this essay. If excitement is added to the equation, my choice would be blue marlin. If sheer power is the only criterion, I’d have to go with the big tuna.

There are a lot of guys who have spent a lot more time fishing offshore than I have, so I sent out a few feelers for votes. Capt. R.T. Trosset, from Key West, Florida, once fought an 860-pound bluefin for seven hours. He also got a leader release on an estimated 1,000-pound blue marlin in 90 minutes. Trosset’s vote for power is the tuna; for excitement, it’s the marlin.

Capt. Rufus Wakeman, of Jensen Beach, Florida, voted for blue marlin, with tuna a close second. The strength and savagery of a hooked blue marlin greyhounding across the surface is what fishing dreams are made of. Every so often, however, a hooked blue simply sounds and never jumps. Wakeman calls that fish a tuna with a point on its nose. If blue marlin fought like tuna, they would be just as exhausting to catch. It’s the magnificent jumping that tires out the marlin and makes it exhilarating and catchable in a reasonable amount of time. There is nothing reasonable (or exciting) about catching a huge yellowfin or bluefin tuna; it’s just backbreaking work.

I also asked world record holder (440 at last count) Marty Arostegui about his experiences. His first choice is tuna, with blue marlin just a hair behind. Arostegui is a light-tackle expert, so his comparison was a 50-pound tuna and a 50-pound marlin. It still was a toss-up in the pure-muscle comparison, but adding the excitement of catching a blue marlin made the difference. Arostegui joins me in imagining little worse than being hooked into a huge yellowfin for hours and hours.

The consensus seems to be that big yellowfin and bluefin tuna are strongest, which probably explains why so few anglers think it’s a good idea to catch one. Blue marlin, however, are a close second and, in my opinion, the ultimate angling experience.

Read about the other fish in our “Who’s the Toughest?” survey here (updated as fish are added): 

Mako: A Memory Maker
Atlantic Salmon: An Acrobatic Prize Fighter
Bluefish: Chaotic Fierceness
Bonefish: Speed, Power and Grace