A newly trained batch of gumshoes are about to enter the hunt for aquatic invasive species, casting a dragnet for insidious foreign infiltrators.

When a concerned citizen calls the state about possibly finding one of the nefarious hostile organisms, these new rookies will be the first ones on the scene to confirm what kind of strange plant or animal the citizen is dealing with: is it a native-born critter, like the virile crayfish? Or an invasive species, like the rusty crayfish? Regular zooplankton, or spiny waterflea, one of the possible culprits ailing the Mille Lacs walleye population? A small regular mussel, or the dreaded zebra mussel?

In order to be prepared to make the right call on those questions, a group of volunteers gathered at the Crow Wing County Land Services building Friday to be trained by the University of Minnesota and the Minnesota Department of Natural Resources' newly formed AIS detectors program. They're the last bunch of 125 total detectors trained statewide this year, intended to be the DNR's first line of defense against possible new infestations.

The students ranged from a crew-cut Douglas County sheriff's deputy with his duty weapon and badge clipped to his belt, to a tie-dye clad woman who wanted to help save her local loon population.

The deputy, Shawn Schmidt, said he was part of an initiative within the sheriff's department to train their deputies on how enforce the state AIS laws when they go on water patrol.

The tie-dye woman, Julie Hepburn, feared for the health of the lake she had been coming to since childhood, Lake Margaret near the town of Lakeshore. She said she already volunteers for the state by tracking loon births. Unchecked AIS will damage the fish population, in turn cutting off the birds' food supply.

"It was heartbreaking," she said of AIS encroachment on her lake. "I don't really like to swim anymore. It's a contagion."

Daniel Larkin, a fisheries, wildlife and conservation professor with the U of M at its Twin Cities campus, drilled the students in identification practice by prompting them to match the names of aquatic plants and animals with specimens the teachers brought. Some of the plants were laminated, while some of the animals to be ID'ed were encased in epoxy, not unlike the mosquitos trapped in amber that caused so much destruction in the movie "Jurassic Park."

Larkin said the practice was designed to be the hands-on phase of their training. The students already received classroom-style instruction via the web. The AIS detectors were also due to be trained on how to deal with potentially challenging people, such as a jumpy citizen or a tenacious reporter trying to get them to say whether a lake is infested with AIS or not. It's important the detectors follow the chain of communication and leave confirming the presence of AIS to the DNR professionals, because an off-the-cuff remark to the wrong person could lead to a public scare, Larkin said.

The detectors also receive instruction on how to use a nationwide mobile phone app called EDDMapS to report potential AIS sightings.

At the end of the class, the students have to pass a test on what they've learned in order to become detectors, Larkin said. There's also continuing education requirements the detectors will have to complete later on in order to stay current. The rigorous training is worth it in the end because the program makes volunteers well prepared to supplement the huge workload facing the 10 paid DNR staff saddled with responding to AIS reports statewide, Larkin said.

"They get a lot of phone calls and emails saying, 'I saw something suspicious, I think it might be invasive.' And that's a lot of work for them," Larkin said. "It might require that they to drive an hour and half to go look at an (lake) access. Or they might get a blurry picture of someone ... holding a glob of green plant, saying, 'I think this might be invasive.'"

Larkin added one of the main goals of the detector program is to help weed out (no pun intended) the false positives. The volunteer detectors aren't allowed to make a definitive, positive ID on whether a lake is infested with AIS, he said-they have to pass it up the chain to their superiors.

Becca Nash of the U of M's Aquatic Invasive Species Research Center said in addition to their tactical mission of identifying AIS in specific lakes, the detectors also serve an overarching strategic purpose by adding to data on how AIS spread in general. The program essentially turns them into volunteer scientists, trained to collect information to higher degrees of accuracy.

"We really wanted a way to get the best known science out in the field as fast as possible," Nash said.

Researchers have learned how to pick out water bodies that might be susceptible to infestations, Nash said. Another DNR job for volunteers is combing these lakes, proactively looking for any warning signs of AIS sneaking their way in. Nash called it "doing surveillance."

Whether the detectors perform stakeouts or respond to citizen sightings, they have their work cut out for them. Research center co-director Nick Phelps used stark words in a May letter describing the task awaiting those dedicated to stopping the threat of invasive species ruining Minnesota waters.

"I am not naïve to the seemingly insurmountable challenges posed by AIS and work every day to address them," Phelps wrote. "I know that solutions will not be easy, fast or cheap. However, I am hopeful for many reasons and believe that if anyone, at any time, could move forward to solve AIS problems, it is Minnesota right now."