It was a sunny day in the city by the bay – or what used to be the community by the bay, back when Hawaiians lived on Hawaii and not tourists. Myself? I was a tourist in the ruins of Kaloko-Honokohau, a fishing village, and I was snorkeling in the remains of the rocky fish pens built here hundreds of years ago.

Kaloko hadn’t been my first choice for a dive. I’d driven out to the old harbor first, but it was closed for road repairs. Then I’d headed back into Kona, passing Kaloko on the way, and tried Disappearing Sands Beach, but the surf was too rough. Just a mile down the road was the more protected Kahaluu Beach, but I’m a conscientious kind of guy and I’d read that the site was so over-snorkeled now that the reef was in danger. Ecologists were encouraging serious water rats to stay away.

So I’d driven back to Kaloko and found a spot on the nearly empty beach. The sandy waters don’t provide a great place to snorkel, but I was to find out that it was the blind goddess justice that had brought me here and not the gods of pleasure.

My name is Preston Filbert, and I’m a national parks nut. I collect visits the way real men collect beer cans, lining them up on the shelf so I can say, “Yeah, I knocked that one down.” I’d been to Kaloko a few days before, but like I’d said, I’d run out of options.

I swam around the shallow bay and spotted a few fish. Some of them were pretty, but like a lot of things in my life, most of them were not. Then I saw him, a pale, pudgy man in floral trunks. Definitely not pretty. He had a small black net on a pole and was scooping up fish, putting them in a yellow plastic container. It looked odd. And not just because of those floral trunks.

Sitting up on the beach I watched for a few minutes more. Nothing about him said National Parks Service; something about him said poacher. I knew there was a ranger station about a half a mile up the hill, so I left my gear in the care of a French-Canadian couple and hurried up the slope.

It was a harder hike than I had imagined. The path was covered with ground-up chunks of lava, winding through the bigger rocks belched forth by some volcano a long time ago. Halfway there I knew I was wasting my time. I figured the park rangers would shrug off my concerns, or the man would be long gone before they ever came down to investigate. I wasn’t worried about the French-Canadians messing with my stuff, though; I figured the worst they’d do was fold my towel for me while I was gone.

At the station, a ranger was bent over a map, showing a visitor where to drive. I told her what I’d seen and she stood upright. I remembered her from my last visit: Nice blue eyes. But my news had turned those eyes to ice. It was gratifying.

“Get in my car,” she ordered. “Give me a description of what you saw.”

We raced back down to the beach, but the man was gone. We talked to an Asian couple that had been snorkeling nearby; they feigned ignorance. I was a little embarrassed, and headed back to my pile of gear and the confused Canadians. I didn’t even know if my park ranger believed me, and it was time to go; I had a plane to catch. But as I passed the ranger on the way out, she said, “We got him! He was a little ways up to the north.”

She said he’d gotten belligerent and they’d had to call in armed backup.

“They took him away in cuffs,” she said, “and we confiscated his gear.”

I was worried about only one thing: “Did you free the fish?”

“They’re back in the bay.”

As I left the park, two more rangers came to meet me. There was handshaking and a reiteration of the arrest. They wanted to know how I’d figured he was a poacher, how I’d gotten up to their station so fast. Probably, I decided, they wanted to know why I had risked my life – or at least my kneecaps – from a tumble on the path.

And then I said it, and it’s become my credo: “No one steals from my national parks.”

I don’t know why they didn’t salute as I drove away.