When it began in 2008, the Gator Bait open water swim was a modest experiment that attracted a couple of dozen local swimmers.

Since then, it’s quickly morphed into something bigger.

The newly rechristened Gator Bait Endurance Challenge begins Saturday at 7 a.m. at Eagle Lake’s Messina Landing. It will include not only the open water swim, but also an Olympic-distance triathlon and a duathlon.

About 175 athletes are expected to participate in the event — six times the number who hit the water for the inaugural swim just four years ago.

Tying into the Gator Bait is a series of nature activities beginning Friday at nearby Tara Wildlife that is expected to attract more than a hundred or so additional people.

“We’re trying to keep it a well-rounded activity,” race director Matthew Mixon said. “We have three distances in the swim, and even have a 12-and-under division. Last year, the kayakers even got together after everything was done and had their own little race. There’s something for everybody.”

Most of the participants Saturday — about 140 of them — have signed up for the triathlon. The race will begin with a 1.5-kilometer swim around a course set up in Eagle Lake, followed by a 40-kilometer bike ride on Mississippi 465 and a 10-kilometer run on Eagle Lake Shore Road.

It’s the second year the Gator Bait has offered the triathlon. Joe Giambrone, a Vicksburg resident who helped set up the course and will race Saturday, said the distance and course layout have made the Gator Bait an instant hit with the state’s triathlon community.

“There’s only two Olympic-distance races in Mississippi, so if you want a late-season race at an equitable distance, this is a good one,” Giambrone said. “Eagle Lake is a great area. It’s flat. It’s easy. There’s great transition areas.”

For athletes who don’t want to get in the water, a duathlon was added this year. It’s a 5-kilometer run, followed by a 40-kilometer bike ride and another 10-kilometer run.

Mixon said only about a dozen athletes have registered for the duathlon this year — the registration deadline is today — but hoped it would grow as another Gator Bait attraction in the future.

“A lot of people were tentative on the distance in the water. It’s a lot tougher than people realize,” Mixon said. “It’s just to attract more people. We’re all about making it a day at the lake. I’d love to see it keep growing and become a weekend extravaganza.”

Gator Bait Endurance Challenge

What: Triathlon, duathlon and open water swim

When: 7 a.m. Saturday

Where: Messina Landing, Eagle Lake

Cost: $30 per person for the open water swim; for the triathlon and duathlon, $65 per person, $90 for a two-person relay team, $100 for a three-person relay team

Registration: The registration deadline is today, and there is no raceday registration. To sign up online for any of the three events, visit vsaswim.org.