My obsession with these fish started seven years ago, when Josh Lane and I stumbled upon them almost completely by accident in the Sakonnet River.

We had left the dock at 4:00 that morning. It was flat calm—the kind of morning that looks beautiful from a boat but doesn't exactly inspire confidence when you're hoping to find bonito and false albacore. The bay was loaded with rain bait, though, and the reports had been favorable enough that we figured it was worth making the run. An hour later, our optimism was disappearing quickly.

We had worked our way through upper Narragansett Bay, across Mount Hope Bay and eventually through the dreaded Tiverton no-wake zone without finding a bonito or albie anywhere. The water was practically glass. Nothing was showing. We were just about ready to pack it in when we saw something about a hundred yards off our port side. Rain bait exploded out of the water. Then it happened again, this time maybe a hundred feet behind the boat. Then again. Within moments, bait was being blown out of the water all around us.

Whatever these fish were, they weren't behaving like the albies we were used to. They weren't racing through the area and disappearing. They stayed put. They were actually cooperating. And we still couldn't catch them.

Josh put cast after cast directly into the middle of the feed. Nothing. I had my fair share of shots too. Nothing. The fish kept pushing rain bait out of the water while we threw everything we had at them. Then Josh finally came tight.

He had tied on a Puglisi Bay Anchovy, and suddenly the rod bent. There was that familiar high-frequency vibration through the line and the initial burst of speed we associated with an albie. And then there wasn't. The fish came off.

"What was that?"

"I think it was an albie."

"Maybe a small one?"

Neither of us really knew. The fish stayed around for another two hours, torturing us until we finally had to point the boat toward home and get to the shop for work. We had made cast after cast without another touch. Neither of us had brought truly tiny flies, so the explanation seemed obvious enough: they were extremely picky albies keyed in on microscopic rain bait. Except something about that answer bothered us.

For the next day or two, it ate away at both of us. We had to go back.

Going Small

A couple of days later, we returned under nearly identical conditions, except this time our fly boxes looked different. We had Puglisi Micro Minnows, Skok Micro Candies and every other tiny baitfish imitation we could get our hands on. I had even tied a few Woolly Buggers on saltwater hooks. We weren't going to be too big again.

By the time we arrived, several boats and kayaks were already working the area. A couple of spin-fishing boats eventually gave up and motored away. Another guy called over to us as he was leaving.

"Good luck. They aren't eating anything."

We tied on our tiny flies. First cast. Game on.

The fish ripped off with that same strange combination we had felt a few days earlier. The burst of speed was there. The vibration through the fly line was there. Everything about the strike said albie. Except the fish didn't pull like an albie.

When we finally brought the first one alongside the boat, we looked at it and came to what seemed like the obvious conclusion. Baby albie. Then we caught another. And another. Two hours and countless fish later, we knew something wasn't adding up. Whatever we were catching, they couldn't all be juvenile false albacore.

Back on shore, we started researching and comparing photographs. Eventually we figured out what had been terrorizing those schools of rain bait. Frigate and bullet tuna. And just like that, we had a new obsession.

Tiny Tuna

Calling these fish "miniature tuna" almost doesn't do them justice.

Bullet tuna, Auxis rochei, and frigate tuna, Auxis thazard, are two extremely similar members of the genus Auxis. They belong to Scombridae—the family containing the mackerels and tunas—but taxonomically they sit within Thunnini, the tuna tribe. In other words, despite names like "frigate mackerel" and "bullet mackerel" sometimes being applied to them, these little fish are very much part of the tuna lineage.

They are also remarkably difficult to tell apart. Both have that unmistakable tuna construction: a compact, muscular body tapering into a narrow caudal peduncle, finlets trailing toward a deeply forked tail and an overall shape seemingly designed for one purpose—speed. The distinction between the two can come down to details in the scaled corselet around the front of the body. On frigate tuna, that rear extension is relatively narrow; on bullet tuna it is broader and extends farther rearward.

But none of that scientific language really describes what they look like when you hold one in your hands. They're spectacular.

Their backs can flash blue, green, turquoise and purple depending on how the light hits them. The sides turn silver with hints of pearl and green, while the darker markings across their backs seem to appear and disappear as the fish moves. Looking at them in bright sunlight, the colors don't seem entirely real. They're tiny versions of the offshore tuna we spend our lives admiring, except we were catching them inside Narragansett Bay on fly rods. That realization was intoxicating.

We spent the rest of that season chasing them. As we learned more, the tackle got lighter. Eventually, five- and six-weight rods became our favorites. On a nine-weight they were interesting. On a five-weight they were tuna.

You could feel everything. The initial hit, the rapid vibration transmitted through the line and the short, frantic runs all became amplified on lighter tackle. They weren't going to take you into the backing like a big albie, but that wasn't really the point. We were catching genuine little pelagics inshore on trout-sized fly rods. It was absurdly fun.

And, at least during those first seasons, it seemed like we had stumbled onto a fishery almost tailor-made for fly fishermen. The spin fishermen around us were struggling because the fish were feeding on prey so small that conventional tackle had trouble matching it while still being able to cast effectively. We could throw a tiny, nearly weightless fly plenty far enough to reach them. For once, the fly rod wasn't a handicap. It was the advantage.

Enter the Scum-Bag Bird

The following year, Jared Koval joined Josh and me in our obsession with these miniature pelagics.

We spent countless days combing the Sakonnet River looking for them, and Jared and I eventually began finding particularly good concentrations around Newport. By then, a few patterns were starting to emerge. Flat-calm days—the conditions that could make traditional albie fishing painfully difficult—seemed to suit these fish perfectly. We found them both in the bay and tucked into larger harbors. Rather than the explosive, chaotic slashing we associated with albies, the little tuna often pushed bait ahead of them in a rolling, wave-like pattern. Rain bait would suddenly spray from the surface, then another patch would erupt a short distance away.

We also became convinced that they had an eye for iridescence. Micro Candies tied with silvery pearl Bodi Braid became favorites. Chartreuse Puglisi Micro Minnows were another. Tiny flies mattered, but so did flash. Something about that pearlescent shimmer seemed to perfectly match the tiny bait they were eating.

Then there were the birds. Whenever we found the tuna, there seemed to be some ratty-looking brown gull hanging around nearby. Unlike the dramatic bird activity we normally associated with a blitz, these birds weren't necessarily wheeling overhead and crashing violently into the water. They were lazy. They would simply paddle around near the feeding fish and wait. The tuna would do all the work, driving rain bait toward the surface, and the gull would be sitting there ready to pick off whatever unfortunate baitfish appeared underneath it.

We started calling them scum-bag birds. It wasn't an ornithologically sophisticated name, but it stuck.

Eventually, the scum-bag bird became one of our most reliable pieces of fish-finding equipment. We'd cruise around looking for rain bait and those lazy brown gulls sitting suspiciously on the surface. Find the combination of the two and there was a good chance something interesting was underneath. All fall, we searched for bait and scum-bag birds. And we caught an awful lot of tiny tuna.

A Fishery That Comes and Goes

The pattern continued over the next couple of seasons, but gradually the numbers seemed to decline. Each year there were fewer fish. The schools weren't as consistent, and eventually those incredible days became harder to find.

Talking with fishermen who had been around these waters much longer than I had, I began hearing the same story repeatedly. They remembered years when frigate and bullet tuna seemed to be everywhere. Some remembered them coming up in nets as bycatch in remarkable numbers. Then they would slowly fade away until they were almost nonexistent. Eventually, according to those fishermen, they'd return and the entire sequence would begin again.

Some put the cycle at roughly eight to ten years. Whether their appearances in Narragansett Bay really follow a clock that precise, I don't know. Fish populations and movements are influenced by far too many things to reduce them to a simple calendar. But I do know what we saw. For a few years they were remarkably abundant, and then there were fewer and fewer.

That's part of what makes this season interesting. We're hearing reports of them in the bay again in decent numbers. I'm hoping that means we're standing at the beginning of another good run rather than the end of one. Because if they return in numbers anything like those first seasons, I'll happily spend another fall looking for scum-bag birds.

The Mini-Tuna Setup

One of the best parts about this fishery is that it doesn't require particularly specialized equipment. In fact, half the fun comes from scaling everything down.

A five- or six-weight fly rod is about perfect. I strongly prefer a rod with an aluminum reel seat because everything about this fishery involves saltwater, and a fighting butt is certainly nice to have. These aren't giant fish, but they're still little tuna, and on a five-weight they can put enough pressure on the rod to make the fight interesting.

An intermediate line has become my favorite. A clear intermediate or clear-tip line is even better, particularly when the water is calm and the fish are keyed in on tiny bait. It lets the fly settle just beneath the surface and keeps the presentation clean without forcing you to fight a fast-sinking line.

Leader construction doesn't need to be complicated. Seven to nine feet ending in roughly 12-pound-test tippet is plenty. The important part is what comes after it. Think small. Really small.

Micro Candies, Micro Minnows and other sparse rain-bait patterns are where I would start. Pearl, silver and chartreuse all deserve a place in the box. Whatever you choose, don't be afraid to fish something that looks almost comically small compared with the saltwater flies you're accustomed to carrying.

That was our mistake seven years ago. We had spent the morning believing we were watching impossibly selective albies when, in reality, something much stranger was happening underneath those scum-bag birds. We had accidentally found a tuna fishery.

Seven years later, I still find something wonderfully ridiculous about the whole thing. We spend so much of the fall searching for bonito and false albacore—watching the weather, chasing reports, running miles of coastline and throwing nine-weights until our shoulders hurt. And then there are mornings when the bay goes flat, the albies disappear and a few little brown gulls begin lazily paddling around a patch of rain bait.

Those are the mornings that now get my attention. Because somewhere underneath them might be one of the smallest tuna I'll ever catch, wearing colors that seem impossible for a New England fish, ready to make a five-weight feel like exactly the right rod.

And seven years after Josh and I accidentally found them, I still want one more.