HALIFAX -- For most Canadians, sharks are objects of mystery and fear -- unblinking, primeval monsters of the deep whose razor-sharp teeth are the stuff of nightmares.

In Nova Scotia, however, for a few weeks every summer they are objects of desire.

Unique in Canada, the province hosts annual shark derbies every August, in which hundreds of anglers pay for a chance to land one of the top predators of the sea.

These fishing tournaments have been closely monitored by the federal Fisheries Department since they started in 1993. Four are scheduled for the next two weekends: two in Cape Breton and two along the province's southwest shore.

"Just to feel it, even if it's a little one, you've got something there that's very powerful," said George Benham, president of the 25th annual Lockeport Sea Derby. "It can run for a minute or two and a time, and the line is flying off the reel. It's exhilarating."

Benham says the town's festival also offers prizes for those who catch the largest mackerel and groundfish, typically cod, pollock and haddock. But it's the big sharks that attract the most attention when fishermen haul them onto the wharf to be weighed and examined by federal scientists.

Benham, a lobster and cod fisherman, admits shark fishing can be dangerous -- "if you're careless."

"If you catch one, and you start putting your hands and fingers around their mouth -- well, that's not a smart thing to do," he says.

"Obviously, you've got a live creature that can be pretty big and powerful with sharp teeth. You treat them with respect."

Virtually all of the sharks landed during the derbies will be blue sharks, the most abundant type of shark off Nova Scotia and southeastern Newfoundland.

Any blue sharks under eight feet long must be released back into the ocean, according to federal rules introduced in 2006.

Benham says the largest blue shark he's seen was about 12-feet long and probably weighed about 400 pounds.

But there are even bigger sharks to be had, though they are rarely caught.

In 2004, a massive 1,085-pound shortfin mako shark was landed in Yarmouth, N.S., where it was hauled away with a forklift, its gaping jaws showing rows of hooked teeth.

The shark derby is Louisbourg, N.S., is called "Mako My Day!"

Thresher sharks are sometimes caught, as are porbeagle sharks. But the endangered porbeagles must be released.

Other species, including the notorious great white, frequent Nova Scotian waters. But most of these fish prefer warmer, deeper waters, putting them off limits to most recreational anglers.

Benham says some visitors have expressed their disdain for the shark derby, a non-profit venture that depends on volunteers and donations. He says it's important to note that relatively few sharks are landed, and the federal Fisheries Department relies on the derbies for scientific research.

Last year, 460 participating fishermen caught 49 sharks in total at Lockeport, Riverport, Louisbourg and Petit-de-Grat, according to statistics compiled by the department, which maintains ownership of the carcasses.

Fishing boat captains who take part in the derbies are told to keep detailed records of their catches and to place tracking tags on the sharks that are released.

Marilyn Sweet, a senior adviser within the department, says the derbies account for only three per cent of the blue sharks killed by fishing-related activities in Canadian waters.

"Blue sharks are very abundant in our waters (and) it's very minimal the numbers that are removed," she says.

"We have a responsible approach to how we deal with the shark derbies. Science has informed us, and we're comfortable with the rates of removal that we have ... It's beneficial to smaller communities and brings in scientific information about a species that is no longer captured commercially."

Virtually all of the blue sharks killed are hooked by fishing boats using long lines to catch swordfish and tuna, she said.

There is no commercial shark fishery in Atlantic Canada, but there are 307 recreational licences for fishing boats that offer catch-and-release voyages -- most of them in Nova Scotia.

The Canadian wing of Humane Society International, an animal welfare group, says shark derbies are "cruel and problematic." But spokesman Gabriel Wildgen says the group is more concerned about the practice of shark finning -- slicing off a shark's fins and discarding the fish into the sea, often still alive but unable to swim.

"We are working to achieve better international protections for sharks under ... international trade mechanisms, and so we aren't focusing on derbies at the moment," Wildgen said in an email.

Finning is illegal in the United States, but American fishermen are still allowed to hunt sharks and have their fins removed during processing on land.

A bill introduced in the U.S. Congress last week would ban the sale and possession of shark fins to ensure U.S. fishermen and seafood dealers no longer participate in the global fin trade, which mainly serves Asian markets and is worth hundreds of millions of dollars.