Pro Fishing Team's 600-lb. Marlin Catch DQ'd in Tourney Over Shark Bites

It's a dog-eat-dog world, but in one pro fishing team's case ... a shark-eat-marlin one too, which ended up costing 'em a ton of dough -- to the tune of millions of dollars!

Officials for the Big Rock Blue Marlin Tournament in North Carolina disqualified a crew this weekend after they hooked a massive marlin that they'd spent upwards of 6 hours reeling in ... and weighing in at over 619 pounds.

It should've won 'em the grand prize. Should have ...

That award would've been a whopping $3.5 million ... but the team, cruising on their boat Sensation, got screwed out of it -- all because their catch had been mauled.

Indeed ... tourney honchos came down with their controversial decision to disqualify the marlin after Sensation landed the massive fish and had taken tons of pics with it hanging over their boat and deck too. Apparently, the thing had significant shark bites in it.

Those bites aren't all that visible to the untrained eye ... the marlin appears to be mostly intact and in good shape -- but, as it turns out, there was enough damage to it for the Big Rock people to cross it out.

Instead, another fishing crew -- riding on a boat called Sushi -- ended up winning with a much smaller marlin ... which weighed only 484 pounds or so. The Sensation team, of course, was bummed about losing out ... saying it was a tough pill to swallow.