The Minnesota Zoo may have some trouble coaxing out some of its critters for a new conservation-focused station opening this spring. These tough and slimy creatures naturally clam up.

The zoo is putting freshwater mussels, all native to Minnesota, on display to promote mussel conservation in partnership with the Minnesota Department of Natural Resources.

The zoo and DNR last year launched a mussel conservation project in the Apple Valley zoo’s main lake, where researchers are culturing young mussels until they can be released into the wild. They’re providing a secure space to raise the mussels up to a size where they will have better odds of surviving their release.

Even though the animals won’t be one of the zoo’s big attractions, officials hope they will draw some onlookers looking to learn about mussels.

“They don’t have a cute, furry face that grabs people’s attention,” said Matt McLaughlin, zoo life support systems coordinator. “Mussels as a group … are considered one of the most threatened groups in North America.”

The zoo researchers are working out of a cabin by the lake that they converted into a conservation station. Once it’s open to the public, visitors will be able to get a close-up look at the mussels and read about the zoo’s effort to save them.

The zoo received its first group of about 150 mussels from the DNR in August. The plain pocketbook mussel was the first species to be introduced to the nutrient-rich lake, followed by the fatmucket and mucket.

The zoo has seen some early signs of success.

“We had some early grows,” McLaughlin said.

In the wild, mussels are facing many threats, with habitat loss being one of the leading causes of their decline. About 28 of Minnesota’s 50 species of mussels are endangered or threatened, or have been driven out of the region, according to the DNR.

Other threats come from dams fragmenting river connections, stream dredging, pollution and zebra mussels — their celebrity cousins whose claim to fame is invading waterways.

Before the zoo introduced the mussels to the lake, researchers tested the water quality to ensure that it could host the mussels. The zoo then installed a pumping system to provide water flow to buckets with mesh screening where the mussels are kept.

“They are filter feeding animals that require constant flow of water,” McLaughlin said.

The whole project is twofold, McLaughlin said. The zoo would like first to sustain a reliable population of endangered mussels for the wild and, secondly, educate the public about the importance of mussels.

McLaughlin said the zoo plans on unveiling the conservation station sometime this spring.

“We hope to have it fully operational for the public,” he said.