HUNTSVILLE, AL—Construction of the Toyota-Mazda assembly plant here has been “temporarily suspended” so that researchers can determine if the project will adversely affect the habitat of an endangered fish.

“This is a short-term suspension that reflects a shared goal of environmental preservation by Mazda, Toyota and the city of Huntsville,” according to the city’s statement. “Crews anticipate construction to resume shortly with minimal disruption.”

There was no indication how long the project suspension would last. The Center for Biological Diversity had said that the project could drive the fish, the spring pygmy sunfish, into extinction, and filed a federal lawsuit last month against the U.S. Fish and Wildlife Service demanding that it protect the fish’s habitat.

The only remaining habitat for the spring pygmy sunfish is Beaverdam Spring and Creek, according to both the lawsuit and the Fish and Wildlife Service. The creek runs north-south in eastern Limestone County, near the proposed site of the Toyota-Mazda plant.

Toyota and Mazda have formed a joint venture to build the $1.6 billion plant. Full-scale construction of the plant is expected to start next year, with operations to begin in 2021. The plant would employ about 4,000 workers.