If you do much fishing, you’ve probably seen fish feeding at the surface of the water. Sometimes the signs of surface feeding fish are subtle. Sardines, anchovies and herrings are primarily plankton eaters, and lots of plankton gets stuck in the water’s surface layer. The “raindrop” dimpling on the surface that we see being made by these small fish is actually a feeding behavior. Each dimple represents a small fish gulping a bit of plankton from the surface.
But sometimes the signs of surface feeding fish are much more obvious. When large predators attack smaller baitfish, the frothy, splashing commotion that accompanies such surface feeding can often be seen from a good distance. These blitzes have cued many millions of fishermen over many thousands of years to the whereabouts of potentially good fishing.
And humans aren’t the only ones to take advantage of a noisy feeding frenzy at the surface. Seabirds are attracted to the fracas in hopes of picking off from above the baitfish that are being attacked from below — creating a real double-jeopardy situation for the hapless baits. Other predatory fish and mammals such as dolphins are attracted to the noise as well. The result can be a multi-species frenzy as thousands upon thousands of the little guys give their lives to support the food chain.
But have you ever stopped to think about why we see this type of action? If the baitfish become exposed to attack from above when they go to the surface, why do they end up there at all? Predators herd baitfish to the top, because to a water-swimming creature like a small fish, the surface of the water is a boundary. Hunters are able to trap the prey fish against the surface boundary from beneath.
We don’t think about it much because we almost never get to see it, but the seafloor is a boundary too. Some predator fish will herd their prey to the bottom and trap them there. King mackerel do this quite a bit, and good kingfish anglers know that if they see schools of bait on their depth sounders that are pushed down tight against the bottom, there’s a good chance kings may be working on them.
But is the surface of the water really a boundary? Anyone who’s discovered their favorite pet goldfish lying dead on the carpet knows that fish can cross that boundary by leaping out of the water. But in the outdoor world, when a small fish leaps out of the water it must fall back — unless its trajectory is intercepted by a seagull or a leaping fish that snatches the poor little guy out of the air in mid-leap.
Have you seen snook, jacks or mangrove snapper popping baitfish at the surface along a seawall? That’s an even better setup for the predators, because they have the baits trapped in a horizontal corner formed by the concrete seawall and the water surface. And if the predators can trap their prey back at the end of a canal in a corner of the seawall, it’s a triple-jeopardy trap for the baits. It’s much like the way we use the corners of our baitwells to trap live baits we are trying to grab to stick on a hook.
Dolphins have this pretty well figured out, and when they are chasing mullet in the canals they often try to push the fish into a seawall corner. The commotion that ensues as the dolphins blast into the hapless mullet is astounding. One Punta Gorda canal resident told me that the first time he heard the noise, he thought it sounded like a horse fell into the canal.
But there’s a catch: Mullet are such great leapers that they can spoil the dolphins’ game by leaping clear over the top of the seawall and landing in the grass. This puts them out of reach of the voracious dolphins, but I’m not sure that flopping around among the fire ants until suffocation finally kills them is any better a fate for a mullet than disappearing down a dolphin’s gullet.
Let’s go fishing!
Capt. Ralph Allen runs the King Fisher Fleet of sightseeing and fishing charter boats located at Fishermen’s Village in Punta Gorda. He is an award-winning outdoor writer and photographer, and is a past president of the Florida Outdoor Writers Association. Contact him at 941-639-2628 or Captain@KingFisherFleet.com.