The Duke O’ Fluke is a floating store that offers products and experiences from the natural world.

Like most stores, there is a core product — it’s namesake flounder — and a diverse selection of other offerings: Birds, marine ecology, sightseeing, partying on the water and other brands of fish.

Captain and owner Brook Koeneke, 75, of North Wildwood, bought the 45-foot pontoon boat in 1995, a decade after it had begun its fishing business out of Margate.

Two years later he moved the Duke O’ Fluke to the municipal pier in Somers Point, where the centerpiece of its offerings remains two four-hour flounder fishing trips every day during the season.

The 14-foot wide and flat boat can accommodate 46 paying passengers and a crew of two, and its stability is as appealing as its easy access to summer’s favorite fish.

“We can claim very little seasickness due in large part to the fact we only operate in the back bay,” Koeneke said. “Anyone prone to motion sickness most likely will have a pleasant experience on a four-hour trip aboard the Duke.”

Like any good businessman, Koeneke keeps his prices competitive with the other activities available to vacationing and local families. Adults pay $24, children $15, seniors $17, and rod rentals are $3.

“Families with a couple of kids are spending far less than they would on three hours on the Ocean City Boardwalk,” he said.

Onto that flatfish foundation Koeneke has built a few other revenue streams that have made the Duke a success.

One is nature tourism, specifically trips to view some of the area’s signature birds in habitats reachable only by boat.

At 6 p.m. Wednesdays in summer, the Duke O’ Fluke leaves the Ocean City Bayside Center for a nature cruise, with guides from the Wetlands Institute in Stone Harbor.

Same time the next night, Koeneke leaves from the Somers Point pier for a bird watching trip with experts from the Cape May Bird Observatory in Swainton spotting and interpreting.

The state’s largest colony of endangered black skimmers — estimated at 3,000 birds — is the centerpiece of that trip, he said.

“We also do, with CMBO, spring and fall trips up the Great Egg Harbor River to look for hawks and eagles,” he said. “That’s a quality trip. People don’t realize the quantity of eagles and raptors along that river. We see a lot of birds on that trip.”

Another important niche for the Duke is school trips.

The Ocean City Intermediate School has a fishing club, for example, and its 20 or so kids usually take three trips a year.

“They hold a fishing flea market in March, and that generates enough money to fund all of the club’s activities,” Koeneke said.

The Egg Harbor Middle School’s top-notch science program has been doing about four trips a year, exploring marine life around islands, picking up trash, and sampling life on the bay floor with a trawl net, he said.

A favorite among several other school trips is one by students of Atlantic County Institute of Technology.

“Most of the students are in their culinary program and they make their own food to bring on the boat,” Koeneke said. “The mate and I wind up getting fed also.”

The final component of the Duke’s business model is party and fishing charters, three-hour cruises late afternoons or evenings. A party cruise for 35 to 40 people costs $550 “plus a tip for the crew,” and the organizers bring their own food and beverages, he said.

To handle all these trips, the Duke employs three relief captains, two regular mates for the daily runs, and several occasional mates for evening work.

Expenses also include a couple thousand dollars a year to have the boat hauled out and stored in Egg Harbor Township, and maintenance and mechanical work each spring and as needed, Koeneke said.

Fortunately, the Duke’s $75,000 cost was paid off after three years, thanks to a big down payment and “a very workable lease purchase agreement,” he said.

The result is a good semi-retirment life for Koeneke, who did “100 percent of everything” his first several years.

“As I aged, the business became more successful, to the point now I’m only on the boat three days a week,” he said, leaving time to go to Cape May for bait and other essentials of his floating business.

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