The fish’s second eye

The Method · September 2026

There’s a version of that morning I still run back sometimes. Early 2000s, walking the beach south of San José del Cabo before the heat came up, no real plan — just covering water, the way you do when you don’t know a stretch yet. I came around a bend and there it was: the estuary had broken through. Estero San José normally sits closed off, a still freshwater lagoon dammed up behind its own sand bar until enough water builds up behind it to blow the barrier out into the Sea of Cortez. It had done exactly that, and the outflow was pouring through a cut in the sand, green — that stained, algae-and-tannin green a breached lagoon puts out, nothing like the blue water fifty yards either direction.

I set up and started working through the box the way you’re taught to: jerkbait, then a soft plastic, then a topwater walking bait worked right along the seam where the green water met the blue. Nothing. Not a follow, not a bump. I’d rotated through four or five things with total confidence and gotten total silence back, which is its own particular kind of frustrating when you can see bait getting pushed through that cut every few seconds.

I had a vibrating blade tied on from earlier — one of those thin metal lipless baits that doesn’t swim so much as buzz, a tight, fast wobble with a lot of thump to it — and I threw it almost as an afterthought on my way down the beach, more out of habit than expectation. It never got more than a few cranks. Game on. And it stayed on: snook after snook, stacked right at that current seam, fifteen or twenty of them over the next couple hours, every one of them sitting in exactly the same three-foot window where the outflow cut the blue.

I didn’t have a name for why at the time. I just knew the blade worked and nothing else had. It took me a long time afterward to actually understand what had happened in that green water, and it comes down to a sense fish have that most anglers never think about: the lateral line.

Distant touch

Every fish has a line of pressure-sensing organs — neuromasts — running down each flank, hair cells that flex when water moves past them, tuned to exactly the kind of low-frequency vibration and pressure disturbance a swimming, struggling, or fleeing animal puts off. It’s sometimes called a sixth sense, or “distant touch” — but on a green-water day, it’s not a backup system. It’s the primary one. There’s research showing predatory fish with their vision blocked can still hunt effectively — but block the lateral line instead, vision intact, and they can’t (lateral line, overview). Whatever a fish’s eyes are doing, it’s the lateral line making the actual strike decision at close range. That’s not a minor sense. In water where the eyes have already given up, it’s arguably the only one still working — which is as close to a second eye as biology gets.

That’s exactly the trade I’d made without realizing it. Every visual bait I’d thrown — the jerkbait’s flash, the walking bait’s surface disturbance — was built to be seen, and there was nothing to see it in. The blade wasn’t built to be seen. It was built to be felt: a tight, high-frequency wobble that pushes a distinct, urgent pressure signature through the water, the kind a lateral line reads as an easy, disoriented target, whether or not a fish could make out its shape (MeatEater; Mississippi Sportsman). In clean water it’s one option among many. In green water pouring out of a broken estuary, it was the only bait in my box actually speaking a language those snook could receive.

The conveyor belt

And the snook weren’t there by accident either. A breached estuary mouth is a feeding station: real baitfish getting swept out of the lagoon on that outflow, disoriented, funneled through one narrow cut instead of spread across open beach. Predators don’t need to hunt a scenario like that — they just need to sit in the current seam and wait for the tide to deliver. My blade bait wasn’t fooling them into thinking it was food out of nowhere. It was joining a conveyor belt of real, vibrating, disoriented bait that was already there, in a signal those fish were already tuned to and actively working.

I didn’t plan any of that. I stumbled onto a broken lagoon mouth on a walk, fished my way through a box of the wrong answers, and only backed into the right one because I happened to have something tied on that spoke to a sense I didn’t even know I was fishing to. But the pattern holds up every time I’ve found it since: green or stained water, current cutting through a defined seam, and a bait built to be felt instead of seen. That’s not luck repeating itself. That’s just fishing to the sense that’s actually switched on.

Sources

• Lateral line, Wikipedia: neuromast structure, mechanoreception, and predation in poor visibility.
• Understand Lateral Lines to Help You Catch More Fish, MeatEater.
• The Lateral Line System (“Long-Distance Feeling”), Mississippi Sportsman.
• San José del Cabo Estuary, Notes From the Road: breach mechanics, sand barrier, outflow.