Captain Frank Crescitelli, known as Captain Frank to his many clients, makes decent money as a saltwater-fly-fishing guide. For backup he owns a small insurance agency, which his wife mostly runs. In his 32-foot, center-console Fin Chaser, powered by two 250-horsepower four-stroke Yamaha outboards and fitted with $20,000 worth of electronics that include a Raymarine digital sonar fish finder, GPS, chart plotter, and mounted video cameras, or in one of his other boats, Captain Frank is on the water about 200 days a year. He puts a lot of fish in the boat—although, following current angling practice and common sense, he lets most of them go. Of all the guides I've fished with, none has had a better success percentage than Captain Frank. What adds an extra level of remarkability to all this is the fact that Captain Frank lives in and guides out of New York City.

He has a house in Staten Island, the city's most rural borough, and he docks at Great Kills Harbor, on the island's south shore. Great Kills Harbor attracts your serious saltwater anglers. Michael's Bait and Tackle, by the marina, sells every kind of saltwater gear, such as commercial fishermen's rain slickers and nautical charts and bags of ice and shark hooks and sand eels and so on. A sign in front of the store announces who is high hook for the past few days. (An angler named Luyen Ng had just caught a 38-pound striped bass off Staten Island's Gateway Park, I noticed recently.) A study of the economic benefits of striped bass sportfishing commissioned by a conservation group, a favored project of Frank's, found that area anglers spent $2.8 million on ice alone in 2003. Obviously, lots of anglers still keep the fish they catch. Every so often, when I get a taste for fresh striper or bluefish, I do too. But never again will I carry a small bluefish of perfectly respectable eating size down the Great Kills dock when the local semi-pro angling dudes are hanging around; last time, somebody yelled, "You gonna get that trophy mounted?" Then all the onlookers haw-hawed as the seagulls shrieked along.

When Captain Frank fishes in tournaments in other parts of the country, he is surprised that people so quickly identify him as being from New York. He thinks he looks like anybody, but he doesn't. His eyes are seawater green; many of his ancestors came from the Piedmont region of northern Italy. His hair, without much effort being expended on it, naturally assumes the shape of a Sopranos-style pompadour. His chest is full and ample, and his posture, in head-to-toe profile, resembles that of a confident Italian tenor. His smile is nearly rectangular and gated by strong white teeth. He laughs unreservedly, gigantically. In the early morning, feeling a bit hungover and fragile, I hesitate to provoke that laugh. But Frank truly and purely loves fishing and fish—all kinds. When you catch a good one, the vastness of Frank's pleasure amplifies your own.

Wherever Frank goes, he wears around his neck a gold chain with a two-and-a-half-inch-long gold charm in the shape of a marlin. He does this because in 2004 he and four friends took Fin Chaser down the Jersey Shore to compete in the annual white marlin tournament out of Beach Haven, New Jersey. Theirs was the only center-console in the competition; most of the other boats were big yachts, million-dollar-and-up extravaganzas. To fish for marlin, you have to go at least 75 miles offshore. Frank and friends got a good soaking from the spray and were tossed around considerably in the open ocean. As one of the competing yachts motored by, Frank heard its captain say over the radio, "Oh my God, these waves are big! I think I just knocked the owner off his bunk." He and his friends still laugh about that one.

Marlin travel in blue water—the warmer water coming up with the Gulf Stream. Frank has a gift for noticing distinctions in ocean water that are invisible to (for example) me. But in order to pin the Gulf Stream's location down even more closely, he subscribes to a satellite service that sends ocean-temperature data over the Internet and updates it regularly. A two-degree difference between one section of ocean and another strongly suggests the Gulf Stream's presence; baitfish tend to hang out along the seam on one side or the other of that temperature divide. Of course, the predator fish, including marlin, can be found there, too.

On the day before the tournament, the satellite could provide no data, because the sky was overcast. Frank thought the weather might clear up later in the night, and he knew the satellite was due to pass over again at about 2 a.m. He stayed up and, sure enough, early in the morning, new temperature data appeared. He downloaded it, studied it, and came up with a new set of numbers about 85 miles out, in an area called the Wilmington Canyon. He and his crew headed there before dawn, found the spot, put out their string of squid teasers. Almost the minute they did, a marlin surfaced, hitting at the squid with his bill. They couldn't get him to strike, however, and they caught no keepers that day. In the evening, back in port, Frank (never a tight-lipped fellow) cheerfully told some competitors that the Wilmington Canyon was the place. The following morning it was full of boats.

But then, in an unusual display of divine or higher-power justice, that afternoon something big took one of Fin Chaser's trailing baits. Frank saw the rod bend; he had forgotten to put on the clicker, and the line was reeling off silently. He quickly set the hook, everyone jumped to his station, and about 15 minutes later they had landed a 57-pound white marlin. When they brought it to the dock and weighed it, it was the biggest fish of the tournament so far.

The next day, word came by radio that another boat, also fishing the Wilmington Canyon, had caught a marlin many pounds bigger. Frank and company stood on the dock with about 100 other people waiting for this other boat to come in. It arrived just before the tournament deadline. The crew jumped ashore, and their marlin was produced and weighed. The needle of the scale bounced to 63 pounds and down to 61, and finally settled at about 54. Fin Chaser's was bigger by three and a half pounds. Captain Frank and his crew divided prize money of $35,000. Frank bought gold marlin necklaces for the crew and himself in celebration.