DULUTH, Minn. - Kassidy is an 8½-year-old girl, and something of a tease.
After leaping high to corral a rubber toy that looks like a dead mallard, the 62-pound chocolate Lab takes a victory lap to the backyard fence, around the garden and directly past Nero, a similarly sized 2-year-old male black Lab being held to wait his turn.
Nero's frustration is palpable. Like Kassidy, he loves to run, leap and fetch. The only thing the two dogs might like better than playing in the backyard of Heath and Kristin Wiersma's home would be having a pool of water to leap into.
Both dogs participate in the sport of dock jumping, with everyone in the Wiersma family - Heath and Kristin, both 38; 12-year-old Kiara and 11-year-old Kylee - serving as handlers. Heath and Kylee work with Kassidy and Kristin and Kiara with Nero, a rescue dog the family adopted from Animal Allies in February.
Competitive dock jumping started in Minnesota and Wisconsin about 13 years ago, said Heath Wiersma, a Duluth firefighter for almost 13 years.
Incorporated as Dock Dogs, it's the fastest-growing canine sport in the world with 10,000 dog-handler teams competing, Heath Wiersma said.
His colleague Perry Ludwig and his dog Lily introduced him to the sport, and when Kassidy was a 1-year-old he gave it a try.
"We practiced one day, and I fell in love with it and Kassidy fell in love with it," he said.
The sport has a junior division for handlers so that Kiara and Kylee can compete in the same events and with the same dogs as their parents.
But the spotlight is on Kassidy because, for the first time, Heath and Kassidy have qualified for the dock-jumping world championship. The event will take place Nov. 13-17 at a convention center in Dubuque, Iowa.
Kassidy was named "biggest-jumping dog" - the overall winner - in four previous competitions this year. It was a fifth event, in which Kassidy placed fifth overall, that won dog and master the invitation to Dubuque.
The competition consists of three events. In "extreme vertical," the dogs leap over the water to snatch a toy - in competition lingo it's a "bumper" - suspended in the air at gradually higher positions.
In "speed retrieve," the dog runs 20 feet on the dock, leaps into the water and swims to the bumper at the end of the pool, 38 feet away from the dock.
In "big air," the handler throws the bumper, the dog leaps off the dock after it, and the distance from the end of the dock to the point where the dog's rump hits the water is measured.
Kassidy will compete in two divisions: the veterans division, for dogs between 8 and 10 years old; and the masters, for dogs that have made five "big air" jumps between 20 and 22 feet in high-level competitions. Kassidy's best jump is better than that: 25 feet 5 inches, still well short of the world record of 31 feet.
But Nero may not be playing second fiddle for long.
"The way Nero is progressing ... I think that he'll be extremely good next year," Heath Wiersma said, sounding just a tad wistful. "He's going to surpass (Kassidy) in everything next year."
There's just a hint of a friendly family competition. When Kassidy's best extreme vertical jump of 5 feet 10 inches was reported, Kristin Wiersma chuckled before announcing that Nero's best was 6 feet. Nero also is slightly ahead already in the speed retrieve and not far behind Kassidy's big air with a best of 24 feet 3 inches.
There's also a chance for intergenerational rivalry. Heath Wiersma said Kylee's best scores with Kassidy haven't exceeded his - yet. Because of Nero's rapid progress, Kiara and her mom kept passing each other's marks all summer, Kristin Wiersma said.
The family aspect of Dock Dogs is one thing both parents said they particularly like.
"It's great time to spend together as a family," Kristin Wiersma said. "And it's something we can do with our dogs. We don't have to kennel them and leave them behind. For us, we got dogs because we wanted companions. And we love having them. We love doing things with them."
Some of the family time includes practice sessions at area lakes from about late May through late August, Heath Wiersma said.
"You bring them to a lake and they see a dock and water; they go berserk," he said. "They love doing it that much."
Many of the dogs in competitions also are hunting dogs, Heath Wiersma said. But although he is a hunter, neither of the dogs hunts with him. There's a possibility Nero might someday. As for Kassidy, it turned out that her love for running, jumping, swimming and retrieving was matched by a distaste for guns.
"She does a great job in the woods until the time I shoot my first bird," he said. "And then she's done."