For the first time in years, Minnesota boaters celebrating the unofficial start to the boating season this weekend will face a new regulation.

A state law took effect May 1 making carbon monoxide detectors mandatory on some boats — the first law of its kind in the nation. Sophia's Law is named for Edina 7-year-old Sophia Baechler, who died in 2015 on Lake Minnetonka when carbon monoxide leaked from a hole in a boat's exhaust pipe.

On Memorial Day weekend, usually one of the busiest boating weekends of the year, conservation officers and other law enforcement agencies will be out in full force on rivers and lakes to educate boaters on the new rule.

"It's a big deal," said Lt. Adam Block of the Minnesota Department of Natural Resources. "There's going to be a lot of retrofitting done."

With relatively cheap gas prices, officers are expecting crowded lakes and rivers across the state, which has 800,000 registered boaters and ranks No. 1 in the nation for most boats per capita.

Already this year, there have been seven drownings and three boating-related deaths, some of the earliest fatalities on record for the boating season. Last year, 17 people died in boating-related incidents.

Law enforcement will be clamping down this weekend on drunken and distracted boating. They'll also be enforcing speed rules, especially with special speed limits on some lakes and rivers, and looking for violations of the state invasive species rules.

"For a lot of people, it will be their first trip out there [of the season]," Block said. "We're anticipating a good turnout and we'll be out there to keep our eyes and ears out."

While pending legislation could push the effective date of Sophia's Law to 2018, as of this weekend, the law is in effect and officers will issue warnings. The law requires any motorboat with an "enclosed accommodation area" — sleeping areas, galleys with sinks, and toilet compartments — to have a marine-certified carbon monoxide detector. All motorboats with "an enclosed occupancy space" — smaller areas into which a person might enter — aren't required to have detectors but must have three warning stickers about carbon monoxide poisoning.

New measures

Officers will also be looking for life jackets, which must be accessible for every passenger and worn by children under 10.

"There's some common sense stuff unfortunately people forget or choose not to do," said Capt. Todd Turpitt of the Hennepin County Sheriff's Office Water Patrol Unit, which covers 107 lakes and rivers including Lake Minnetonka. "A lot of [accidents and fatalities] are preventable."

Seven deputies will patrol Lake Minnetonka, the metro's most popular lake, which got a new emergency access dock last year.

Elsewhere, boaters won't be going full throttle on waterways including Lake Independence near Maple Plain and the St. Croix River in Taylors Falls, which have 5 mph speed limits due to high water levels.

Throughout the state, 150 DNR conservation officers will also be deployed this weekend to enforce rules — along with new canine experts.

The DNR added two pointers to its K-9 division of four dogs, one of which will be on Lake Minnetonka and neighboring lakes, sniffing out hard-to-detect zebra mussels on boats. The DNR introduced the dogs in 2013, only the second state to do so.

To help prevent boats from spreading invasive species from lake to lake, more decontamination units and watercraft inspectors will be at public accesses this year. Last year, more than 900 DNR-trained inspectors were checking boats at public accesses.

Since 2010, state law has required boaters to remove the drain plug, clean off weeds, and drain water from bait buckets and livewells before transporting a boat, or risk a $100 to $150 fine. Transporting zebra mussels results in the biggest hit: a $500 fine.

The DNR says the number of violations has dropped as boaters have gotten used to the new norms. But there's still a lot at risk. While more than 800 Minnesota rivers, lakes and wetlands are designated by the DNR as infested with aquatic invasive species such as Eurasian watermilfoil or zebra mussels, most of Minnesota's 11,842 lakes aren't infested.

"It may sound like it spread statewide, but it isn't," said Jackie Glaser, DNR enforcement operations manager. "There are way more lakes that aren't infested."

Kelly Smith • 612-673-4141