Work has stopped at the construction site of a massive Mazda-Toyota assembly plant to ensure that a threatened species of fish that lives nearby will be protected.

The spring pygmy sunfish, listed as a threatened species by the U.S. Fish and Wildlife Service, lives in Beaverdam Creek in the Mooresville area. 

Toyota and Mazda have a joint agreement to build a $1.6 billion plant that will produce Toyota Corollas and a new crossover vehicle from Mazda.

Production is expected to begin in 2021, but initial groundwork has stopped at the site while surveys confirm that the new plant will not impact the sunfish's environment.

"Mazda and Toyota continue to make environmental preservation a priority and we are committed to developing the property sustainably," Toyota spokeswoman Kim Ogle said.

The Arizona-based Center for Biological Diversity has said recently that it plans to sue the U.S. Fish and Wildlife Service for failing to designate the area around the creek as a protected critical habitat.

Ogle said Toyota and Mazda are working with the city of Huntsville and the U.S. Fish and Wildlife Service to ensure that the fish's habitat is protected.

"We anticipate that this will be a short-term suspension and that construction will resume shortly with minimal disruption," she said.