(CNN) -- They can reach lengths of 18 feet and their numbers are estimated to be in the tens of thousands, but Burmese pythons, a nuisance in the Everglades, aren't easy to find.
"It's an amazing challenge to try to come out and hunt these big snakes," hunter Dennis Jordan told CNN Miami affiliate WSVN in the closing days of the 2013 Python Challenge sponsored by state officials.
The Florida Fish and Wildlife Conservation Commission announced Saturday that 68 Burmese pythons were killed during the January 12-February 10 competition that drew 1,600 registrants lured by prizes of up to $1,500.
Though the take was small, wildlife officials said their main aim was heightening public awareness of the invasive species.
"Thanks to the determination of Python Challenge competitors, we are able to gather invaluable information that will help refine and focus combined efforts to control pythons in the Everglades," commission executive director Nick Wiley said.
State wildlife officials say there may be as many as 100,000 Burmese pythons living in the vast swamps outside Miami. By comparison, the state is home to about 1.3 million alligators.
"You can go out there for days and days and days and not see one python," snake hunter Justin Matthews said last month. "I don't care how much experience you have. It is going to take some luck."
Hunters covered a million acres of swamp and sawgrass, officials said.
The pythons began turning up in the Everglades in 1979, most likely abandoned by pet owners when the snakes got too big to handle. They have no natural predators.
Rabbits and foxes have disappeared, while raccoon, opossum and bobcat populations have dropped as much as 99%, researchers at Virginia Tech University, Davidson College and the U.S. Geological Survey reported in 2012. The U.S. Fish and Wildlife Service has banned the importation of Burmese pythons, along with three other exotic snake species and their eggs.
While the pythons can run to double-digit lengths, University of Florida wildlife ecologist Frank Mazzotti said the average snake runs about 6 to 9 feet.
State officials recommended shooting the snakes in the head or decapitating them with a machete.
Hunter Brian Barrows of Fort Myers won a $1,500 grand prize in the amateur category for harvesting six pythons, as did Ruben Ramirez of Miami, who bagged 18 of the creatures in the competition for professional hunters.
Paul Shannon of Lehigh Acres won $1,000 for the longest python, which stretched 14 feet, 3 inches.
CNN's Phil Gast and Matt Smith contributed to this report.