KENNNEWICK — Six months after sturgeon hatched at Pacific Northwest National Laboratory, the creatures are swimming around an indoor tank, thanks to a major upgrade of PNNL’s Aquatic Research Laboratory.

The $4.9 million project remodeled 40-year-old laboratory space that was “a dark, dingy, dank, water-leaking place,” said Julie Erickson, deputy manager of the Department of Energy’s Pacific Northwest Site Office.

But it also enclosed the lab’s outdoor fish tanks in a 5,500-square-foot indoor space for a total of 7,400 square feet of space.

The improved laboratory will allow scientists to do new research because it has better control of variables such as water quality and temperature, and it will hold more fish and different kinds of fish, said David Geist, technical group manager.

The lab develops the science that helps leaders make critical decisions, said Mike Kluse, PNNL director. Its focus includes research to improve hydropower dams, make decisions about the cleanup of Hanford and other waste sites, and assess climate impacts, he said.

Now the aquatic research lab conducts $15 million of research annually, much of it focused on better ways to operate dams used for hydropower.

Researchers can draw on PNNL’s wide range of expertise in engineering, biology and computational mathematics to develop ways to operate dams safely for salmon but in ways that keep electrical costs down for utility customers, Geist said.

Among the fish swimming around the new indoor tanks are the juvenile sturgeon, just a few inches long now but looking much like the 10-foot-long, bony-plated adults they could become. In another tank are rainbow trout, weighing at least a pound and a half each. Brightly colored tropical fish are kept for international work.

“Fish are happier,” Geist said, summing up the improvements to the lab that began three years ago.

The remodeled lab near the banks of the Columbia River in Hanford’s 300 Area can use river water now that the lab has a water treatment system. It filters the water, treats it to remove disease-causing pathogens and then heats or cool it to the desired temperature.

Research includes work with juvenile lamprey. Not much is known about what habitat they prefer, said research scientist Bob Mueller. The goal is prevention of destruction or contamination of their preferred habitat.