Fishing for blackfin tuna? Here is a great and fun place in the Florida Keys to do that

Fishing for blackfin tunas can be excellent on the humps off the Florida Keys.
Fishing for blackfin tunas can be excellent on the humps off the Florida Keys.

Catching blackfin tuna around the humps off the Florida Keys can be as simple as trolling lures or as labor intensive as catching and chumming with live bait. Either way, the results are delicious.

Pulling a skirted lure, a feather or a swimming plug well behind the boat typically catches tuna 5 to 10 pounds, although larger fish sometimes bite. Live baits such as pilchards usually catch the bigger tuna, which can range from 15 to 30 or more pounds.

There are three primary humps in the Keys. They are underwater sea mounts that rise from the ocean floor to within several hundred feet of the surface and they create upwellings that attract bait. The bait attracts a variety of gamefish, including dolphin, wahoo, sailfish, amberjacks and sharks.

Most anglers head to the humps in search of blackfin tuna, which are around most of the year. Their dark, red flesh is excellent table fare whether sliced thinly and eaten raw with soy sauce and wasabi or cut into steaks and seared on the top and the bottom in a hot skillet, leaving the interior rare or medium rare. Blackfin chunks and steaks marinated in teriyaki sauce are also great on the grill.

The Islamorada Hump, which is less than 300 feet from the surface, is the easternmost of the humps. Next is the 409 Hump, which is 409 feet below the surface. The Marathon or West Hump is the westernmost mount and less than 500 feet from the surface. Big tuna are typically at the Islamorada Hump through the end of this month, at the 409 through July and at the Marathon through the summer.

As you arrive at a hump, you can put out two or more trolling lures anywhere from 300 to 500 feet behind the boat on 20- and 30-pound outfits. Generally, the farthest lures get the most bites.

Another lure that works well at the humps is a butterfly or vertical jig, which is a slab of metal painted to look like a fish with a free-swinging hook. The jig is dropped down 100 or more feet, then jigged up and dropped down over and over again. Tuna that are well below the surface near the humps will hit the jigs, but so will amberjacks.

Live baits can also be fished 100-200 feet down on the humps using a sinker attached to the fishing line. The boat can simply drift around the humps while the angler waits for a tuna to strike.

Serious tuna fishermen like to go to the humps with 100 to 500 live pilchards, which they catch on sabiki rigs or with cast nets. The pilchards not only serve as bait, but also chum to get the tuna to the surface.

Anglers can toss five or 10 pilchards at a time into the water behind the boat every five minutes. As the little baitfish swim around, tuna will splash, or even go airborne, as they try to eat them.

Pilchards hooked through the nose or towards the back, which makes them swim deeper, can then be drifted back on 20-pound spinning outfits. Make sure there is no tension on the fishing line so the baits swim naturally as they get to where the tuna are busting. Tuna have excellent eyesight, so using fluorocarbon leaders, which are invisible in the water, and small 3/0 to 5/0 circle hooks will get more bites.

Be aware that multiple hookups can occur when the tuna are chummed up and in a feeding frenzy. That can result in crossed lines, so it’s important for anglers to pay attention to where their fish are headed so they can go over or under a fellow angler’s fishing line.

On a recent live-chumming trip to one of the humps, four of us were hooked to blackfins at the same time and we landed all four thanks to some excellent choreography by the mate, who had us going from one side of the boat to the other. One time we lost a fish when a monofilament line was crossed by a braided line, which cut through the mono like a knife, and a couple of times we had some tangles that cost us a fish.

Tuna at the humps can also be lost to sharks. An angler will be fighting a blackfin and reeling it closer to the boat when it suddenly takes off. That’s the shark chasing or swimming away with the tuna. When the shark bites the blackfin, the fishing line goes limp and the angler reels in half a tuna or less.