By: Capt. Joel Brandenburg
When it comes to offshore fishing in the Florida Keys, few destinations compare to the Marathon Humps. Situated about 27 miles offshore of Marathon, these underwater seamounts rise dramatically from the ocean floor, creating a unique environment where currents collide and baitfish gather. This natural upwelling turns the humps into a year-round feeding ground for pelagic predators, with blackfin tuna being one of the most sought-after catches. Anglers from around
the world travel to Marathon to test their skills against these hard-fighting fish, which are prized for both their strength and table quality.
The Marathon Humps consist of three primary rises: the West Hump, the 409 Hump, and the Marathon East Hump. Each one is a hotspot where nutrient-rich waters attract schools of flying fish, squid, sardines, and ballyhoo. Blackfin tuna, the smallest of the tuna species, thrive here in impressive numbers. Ranging from five to 30 pounds, they are fast, aggressive, and incredibly strong for their size. The humps offer consistent action nearly year-round, with peak blackfin seasons occurring in spring and fall when the schools are at their thickest.
There are several productive methods for targeting blackfin tuna at the Marathon Humps, each catering to different conditions and angler preferences.
Live Bait Drifting;
One of the most effective tactics is drifting live baits such as pilchards or cigar minnows over the humps. Many captains recommend catching a livewell full of pilchards before heading offshore. Once you arrive, you can deploy a steady chum line of live baits, often called “live chumming.” This excites the blackfins and brings them right to the boat, often within sight of the surface.
Vertical Jigging;
For anglers who enjoy a hands-on, high-energy method, vertical jigging with heavy metal jigs can be extremely productive. Dropping a jig to depths of 200–400 feet and working it back up with quick, erratic motions mimics fleeing baitfish. Blackfins often strike suddenly and without hesitation, giving anglers a direct feel for the fight.
Trolling;
Trolling small feathers, cedar plugs, and rigged ballyhoo around the humps is another classic method. This technique allows you to cover more ground while searching for schools of tuna. Trolling also offers opportunities to hook into other pelagic species such as mahi-mahi, wahoo, or even the occasional billfish.
Chunking;
Another tried-and-true technique involves cutting up fresh baitfish into chunks and tossing them overboard to create a feeding frenzy. With lines baited and set at varying depths, anglers can pick off blackfins one by one as they move in to feast.
Blackfin tuna fight far above their weight class, proper tackle is essential. Medium spinning or conventional setups spooled with 20–40 lb. braid or mono are standard, matched with fluorocarbon leaders in the 20–30 lb. range. The fish have sharp eyesight, so light leaders often produce more bites. Circle hooks are preferred, as they help with solid hooksets and improve the chances of releasing fish in good condition.
Once hooked, blackfin tuna provide a thrilling battle. Their stamina and speed make them one of the toughest pound-for-pound fighters in the ocean. After the fight, the reward is equally satisfying. Blackfin tuna are excellent table fare, perfect for sushi, sashimi, seared steaks, or grilled fillets. Because they don’t grow as large as their yellowfin cousins, icing them quickly is critical to preserving the quality of the meat.
As with all fisheries in the Florida Keys, sustainability is important. Anglers should stay current on bag limits and size regulations set by the Florida Fish and Wildlife Conservation Commission and federal authorities. Responsible harvesting ensures that future generations will continue to enjoy the thrill of fishing the Marathon Humps!
— For a charter with Captain Joel Brandenburg of Ana Banana Fishing Company Marathon Florida Keys call 305– 395–4212 office# or 813–267–4401 Cell #. Or visit us in person at ponchos fuel dock a half block away from Cast Away restaurant at 1280 Oceanview Ave. Marathon Florida Keys.