PINE HAVEN, Wyoming — Weston Rosenau floated on the lake surface Saturday morning, barely visible in a dark, camouflage wetsuit. Behind him trailed a bright yellow buoy with a red diving flag. Suddenly, Rosenau dove, flippers sticking up in the air before nothing remained by the buoy and flag.

Seconds turned into a minute. The minute passed with no sign of him. After what seemed like an eternity, Rosenau broke back through the surface holding a spear with a flopping bright gold and yellow carp; it was his first fish in Keyhole Reservoir that morning.

    He shook his head as he swam with his speargun and fish to a nearby pontoon boat. “I need fish,” he said to the boat driver. “Take me over there to that rocky point.” Rosenau, 25, had no time for pleasantries. He and partner Brandon Miller, 31, were competing in the first Freshwater Spearfishing Nationals tournament in their home water. They finished in fifth place Friday against teams from as far away as New Zealand and Hawaii, and as close as Gillette and Douglas. Saturday’s goal was to break into the top four by shooting the most pounds of carp up to 50 fish each.

The weekend’s tournament was only the second national championship in Wyoming, and the first one for Miller and Rosenau. If they didn’t place higher after Saturday, they at least hoped to increase visibility and understanding of their sport among traditional anglers.

    Spearfishing, they both said, requires fishermen hold their breath for minutes at a time and dive deep into murky lakes and reservoirs. It’s the best of both fishing and hunting. “Sometimes the fish come right up to you, but other times you have to go down and hide by a rock,” Miller said. “When a fish floats by you have to slowly move by and creep up to it and find the right time to get your shaft in them.”

And all without running out of air.

Freshwater spearfishing, as practiced during tournaments such as the Freshwater Spearfishing Nationals, is a relatively new sport in the U.S. and its rules are a complicated list of fish limits and equipment restrictions. In some states, such as Florida, freshwater spearfishing is illegal. Other states prohibit spearfishing game fish, Rosenau said. Wyoming allows spearfishing, but restrictions vary depending on fish species and the individual body of water. In Keyhole, for example, rod and reel anglers are allowed to keep six walleye, while spearfishermen are allowed only two.

One of the most important, and basic, spearfishing regulations states that all spearfishermen must be completely submerged before shooting a fish. That means no standing on shore or leaning over the side of a boat to spear a walleye or crappie, said Andrew Nikirk, Sheridan region fisheries biologist with the Wyoming Game and Fish Department.

    While underwater, anglers can use spears, or guns that shoot spears, but the line attaching the spear to the gun or person can be no longer than 20 feet. “It can only be done in lakes, and can’t be within 100 yards of a boat,” Nikirk said. “Diver’s flags must be displayed to identify locations for other boaters.”