What do anglers like almost as much as catching fish? That’s an easy one: looking for fish.

And so it is that, in its fourth year, the Brook Trout Survey Project has signed up 850 volunteers, of which more than 200 have actually made it into the field, surveying ponds where brook trout seem likely to be but have never been confirmed.

Amanda Moeser, the project’s volunteer coordinator from 2011-12, has returned this year, and says it’s a “pretty solid” citizen science effort that continues to attract new participants.

Based at Maine Audubon, she does outreach through fishing clubs, media appearances, sportsmen’s shows and, this year, social media. “A lot of it’s word of mouth,” she said. “This is a topic that catches people’s attention.”

Most of the volunteers head out into the field, either close to their homes or for a new adventure, to one of the hundreds of ponds in the far northern and western reaches of Maine. Some tie flies and help with data analysis.

A few of the ponds are big enough for a plane to land, but most are less than 10 acres, and can be reached only on foot. “Some are close enough to a road so you can see your way in,” Moeser said. “But for most of them you have to bushwhack.”

Occasionally, the pond can’t be found, possibly because the aerial surveys being used are up to 50 years old. “They might have dried up or changed position,” she said of the ponds.

And, occasionally, someone gets lost, but not for long — everyone’s returned safely so far. A GPS device is recommended but not required.

The volunteers are vital to the success of the project, Moeser said. “There’s no way the IF&W biologists could cover all these ponds on their own.”

Though many ponds remain to be explored, the project is expanding this year to include the coastal streams and rivers that also contain brook trout, though they have clear differences from their inland cousins. Some brook trout, dubbed “salters,” spend significant amounts of time in ocean water, for reasons that scientists haven’t yet determined.

“There’s still a lot that isn’t known” about brook trout, she said.

The expanded effort should benefit the project, which is funded at least through 2015. “A lot of people prefer stream and river fishing, and we can take advantage of their knowledge, too,” she said.

Moeser has also worked on citizen science projects in the far West, and in urban environments such as the Bronx borough of New York City, where she focused on eels and elvers as part of her graduate work at Antioch University in New Hampshire.

As with brook trout, Maine has one of the largest eel and elver runs in the continental U.S. “It’s great to be in a place that has so much to conserve,” she said.