It's the Little Details that Count When You're Fishing Offshore

Sometimes the most important road signs in the ocean are in the fine print.

January 02, 2025 By Jeff Weakley

Offshore there are big obvious things like swarms of bait getting rocked by tunas; vivid, current-swirling color changes; huge, bait-clouded reefs that blot out the sonar screen.

We dream about stuff like that, but often it’s the little things that make the day.

Earlier this summer, my oldest daughter was counting Portuguese man o’ war along a vague weedline off Fort Pierce—more a sprinkling of grass than anything else. It was around 10 a.m. and fishing had been slow all morning, just a couple of bonitos.

What do you do on a slow day but idle along a weedline and count jellyfish. That or park on a reef and dip chicken rigs for grunts and such. Too hot for the latter. Our instinct was to keep a little wind in our face as we watched the ocean to admire its ephemeral beauty. Turns out someone else had the same idea.

Beneath one of the diaphanous, neon-tinged jellyfish was a flash of green and yellow. My daughter saw it first. A nice mahi had been patrolling this little edge, likely hunting the little jacks and other fish that gather wherever plankton piles up. Which, of course, is exactly where jellyfish tend to pile up.

I had a nose-hooked thread herring swimming on a flatline behind the boat, and before I could pick up a rod, that dolphin jetted away from the man o’ war and inhaled the bait. Our fortunes had changed. Soon we had a second mahi in the box, plenty for dinner and some to share with neighbors.

Three photos of a herring bait, tripletail fish, and young woman holding a mahi-mahi. — The dolphin (right) was hooked on a live herring (top left) fished near a couple of Portuguese man o’ war. The buoy-hugging tripletail (below left) made it to the net by way of a live shrimp.

Small Floaters

Whether it’s a jellyfish, an errant lobster trap float, a palm frond or even a bucket, little things drifting at the surface can be big attractions in the bluewater fish world.

There are two attributes which seem to up the fish-producing potential here. One is time in the water. The longer a piece of debris floats at sea, the more algae builds up on it, lending to the familiar food chain where small browsing fish pick away at the growth and larger fish move in to pick off the smaller fish. Smaller fish apparently also regard the structure as a safety zone, a place to hide from predators. Lift a piece of old rope, for instance, out of the water and there’ll remain a cloud of fish that will instantly gravitate back to the structure when you return it. (Rope is always a great find!)

Basically, the dirtier and dingier the better, when it comes to small floater finds. A clean foam marker float, recent flotsam, may not hold much, but one that’s covered in algae and attended by little fish is always worth a cast.

The other thing besides time in the water is depth penetration. A floater that reaches down several feet beneath the surface—like a vertical tree trunk, or perhaps best of all, a huge palm frond with leaves sweeping down under the surface—is a super find. Nothing better. What amplifies the attraction here may reflect a few things. Depth, obviously, gives fish room to space themselves out, increasing the potential holding power—the effective biomass. Another thing is, a thin piece of material barely submerged, reaching down a ways, is not easily recognizable to other anglers. It’s hard to miss a big log floating high and perfectly horizontal—if you don’t spot the log immediately at a distance, good chance you’ll see the white of seabirds sitting on it. The high log, assuming no boats are fishing it already, is always a good prospect… but just because no boats are currently there doesn’t mean others weren’t there already. The condition is much the same with reef fishing—often the large shipwrecks and rubble piles are pretty well picked over by anglers, whereas the little rock you spy in uncharted terrain could hold a pod of mature, unfished groupers.

One of the best floaters I ever saw was a single barrel out in about 200 feet of water, past Sand Key Light off Key West. The barrel itself was pretty clean, totally submerged but for a little rim that popped above the surface now and then. It was not drifting in any kind of obvious fish-holding water. No big rip, no parade of sargassum, just a barrel that had evidently fallen off a ship or been swept out of some storm-rent harbor.

The captain of the Garrison Bight charterboat I was on at the time, knew there’d been a few wahoo around, and he wisely steered our skirted ballyhoo around that barrel to see if anyone was home. Home is not the right word. This was a high-rise wahoo condominium! We caught wahoo for sure—14 of them. They weren’t big, maybe 15 to 20 pounds max, but neither were they “wee-hoos.” In hindsight, we kept too many of them, but the event sticks in my memory.

I learned long ago—from an assortment of captains and other sources—that dolphin seem to prefer water at or above 78 degrees F. Indeed, I can recall trips where that figure—and little else—coincided with a good bite. Of course, there seems to be nothing about a dolphin’s physical makeup that limits its ability to survive in cooler or hotter water. Seventy degrees is certainly not fatal, and neither is 88 degrees. You could find dolphin in this range. But that 78 seems to be a trigger. Captain Rick Ryals, who years ago wrote a book on the subject, related research indicating spawning may occur at, and possibly not below, that 78-degree figure. Unsurprising in the least to find creatures gravitating to a favorable spawning condition—much like humans drawn to a scenic beach or bustling nightclub. Speaking of night clubs: Recent research, published by the University of Miami, narrows that dolphin preference window to 80 to 82 degrees F. Additionally, the researchers found mahi spawn at night, and down deep, during a new moon.

So there’s a bit of gray area in terms of exactly where dolphin roam depending on their thermoregulatory needs. The figure might be 78, or it might be 76. Or 80. The real key here is your attention as a fisherman: If you’ve pegged a particular temperature, and you’re watching your plotter screen while running the boat, or scanning online satellite imagery—you’re now attuned to change. Change, and not a specific number, is often the subtle sign of mixing water bodies—edges where shelf water meets the fractal swirls of Gulf Stream eddies, for example. These are naturally where plankton tends to build up, and fast-growing plankton-feeders like sardines, juvenile flyingfish, jacks, and small fish concentrate. Find the sudden break—or even the slight rise or dip in temperature—and you might have uncovered a gamefish foraging zone.

Works same for wahoo, tuna, billfish—find your source (there are many) for optimal temperature ranges, discuss local preferences with trusted sources, then keep an eye for where that figure arrives. Does it suddenly—within a short distance—rise from 76 to 78 degrees? See if there’s a subtle change in the water color or accumulation of grass in the area—that could be the rip that’s holding the dolphin. But even if there are no other apparent signs of life, spend some time along the transition zone.

Tiny Bottom Breaks

No discussion of the “big little things” would be complete without some account of subtle bottom structure. Not to say we should pass up 300-foot steel freighters looming like fish apartments in the ocean currents, but we should also be constantly on the lookout for small, outlying features that are, in many cases, heavily populated and lightly fished.

In a recent issue of this magazine, writer Steve Dougherty touched on the relationship between African pompano and the pocked, eroded limestone bottom found in much of the Gulf of Mexico. African pompano are generally regarded as “reef fish,” along with snappers, groupers and amberjack, but pursuant to Steve’s article, all these types may be present on structure that hardly registers on a sonar. The structure—complete with attendant benthic life and prey fish—could very well be the inverse of a reef, a hole in the bottom of the sea!

Watching the fishfinder while trolling or relocating is a good way to find off-the-grid reefs or holes. We pretty much all look for sudden depth changes, thickening (or reddening) bottom line indicating hardbottom, and seemingly random patches of midwater life—the kind of stuff that says, “Stop here, look around!”

Sometimes you find all three conditions in one zone, sometimes one or two. As with water temperature, it’s good to focus on change. Where the hardness of the bottom abruptly changes on your fishfinder screen, regardless of depth or apparent “shows” of fish, can be a day-saving drop. Spending some time idling in the area may reveal the rest of the story: A ledge, a rockpile, an old wreck not on your chart.

A Little About Birds

Lastly, seabirds are a traditional sign for offshore fishermen, but of course there’s hardly a one size fits all here. Terns, with their dagger-like beaks, are geared up to dive hard and spear or grab live fish. The best ones are the real offshore roamers, the sooty terns, with their chocolate topside feathers. Frigate birds, unmistakable black pirates of the sky, are good fish-pointers, always surveying the water and skies in a wide radius, looking to grab fish chased up by dolphin or tuna—or to pilfer catches from the terns.

If you find a real bonanza of birds, it’s obviously worth inspection. But if the birds are moving fast—as they were for us a few months ago off Key West—likely they’re on skipjack tuna. The Key West captain I was fishing with, TV host Rush Maltz, had pulled up a few blips on his Furuno radar in bird mode. We ran out to the area, but Rush soon noticed the birds weren’t staying in one place. There were terns and shearwaters down low apparently chasing bait, a few frigates up high, but they were moving fast—like 20 mph fast. We made a few passes to intercept them, and did manage to catch a small mahi, but it was pretty clear this was skipjacks. Skippies can be fun to catch—and pretty good to eat—but if you have other goals, they can also be sort of a time and fuel suck.

Rush suspected blackfins would be in shallower. And he was right. We pulled away and set up in about 200 feet of water, freelining pilchards as the captain sent chummers upcurrent, slapping them out of his bait net. A lone shark, possibly a silky, cruised along the boat for a moment. One random predator in open water? The tiniest sign. Soon eruptions appeared where our chummers landed. The blackfins had found us. Our day was made.