As energy costs have risen in recent months and America has, once again, begun paying attention to our nation's dependency on foreign oil, both individuals and businesses are taking a hard look at energy consumption -- with many making changes in the way they do things to conserve energy and save money.

This is true for the Michigan Department of Natural Resources, which has adopted a number of strategies to reduce its energy use and implement "green" building and maintenance practices at many state parks and field offices, and even at all of the DNR's six fish hatcheries.

Raising millions of fish from egg-take to stocking size -- and for some species, that's an 18-month process -- is obviously an energy-intensive affair as most water pumps, oxygen generators, water heaters and other equipment runs almost nonstop.

So the first step toward energy efficiency was for hatchery section employees to conduct a complete energy audit at each of the facilities.

Some of the initial actions taken were very simple, such as turning off the light switch when leaving a room or turning down thermostats. In some places, personnel were slightly more proactive, swapping out older fluorescent light bulbs for newer, more energy-efficient models. But a few bigger changes have yielded better results.

Most state fish hatcheries now use only well water these days to help prevent introducing any pathogens -- such as a virus or bacteria -- into the hatchery system. The pumps moving the water from these wells into the fish-rearing facilities run 24 hours a day, 365 days a year. That requires a lot of energy use.

"One major improvement was the installation of variable-frequency-drive controls for many of our pumps to allow for better control of water and energy use," said Dave Stine, a maintenance mechanic at Oden State Fish Hatchery. "The motors can be set to pump a specific amount of water, which causes the motor to use only the necessary energy to pump that specific amount of water."

The savings have been significant.

"You really need to look at how and when you are running your wells," said Jon Jackoviak, fisheries biologist at the Harrietta State Fish Hatchery. "We have reduced our electricity usage at Harrietta by nearly 15% over the last few years by managing our water use more efficiently."

Hatchery section personnel also travel some 120,000 miles every spring delivering the fish they produced to their stocking locations. That endeavor demands approximately 17,200 gallons of fuel. In an attempt to throttle back on the petroleum consumption, the hatchery section began experimenting with biodiesel fuel in 2007.

The Platte River State Fish Hatchery was the test site for the first run of the alternative fuel, running its trucks on B-5, which is a mixture of 95% ordinary diesel fuel and 5% biodiesel.

"Originally we were going to use B-10, but with the cold temperatures and the recommendation of the manufacturer, we decided to go with B-5," said transportation mechanic Phil Sedelmaier. "We used it in four different vehicles totaling around 22,500 miles for the year. The vehicles ranged from small trucks to semis, from a little more than 10- to 17-years-old, and the trucks had a wide range of mileage on them. We did not have a single fuel-related breakdown, so we decided to try it on more vehicles in 2008."

Last March, temporary tanks were delivered to the fish hatcheries at Platte, Harrietta and Oden containing B-10 biodiesel. To date, this fuel has been tested in nine different vehicles, ranging from a 1991 model to a brand new truck. Over the course of nearly 75,000 miles this spring, there were no fuel-related breakdowns and no noticeable loss of performance or mileage on any of these vehicles.

"Although there has been only minimal savings in our fuel costs, everyone is pleased that we were cutting down on petroleum consumption by investigating alternative fuels," Sedelmaier said.

DNR Fish Hatcheries are not just using alternative fuels; in one case they have eliminated the use of energy altogether while keeping their raceways aerated.

Several years ago at the Wolf Lake State Fish Hatchery near Kalamazoo, hatchery personnel began experimenting with liquid oxygen instead of using oxygen generators.

Today, most hatcheries now are equipped with industrial-sized liquid oxygen tanks, like those you might see at a hospital. The tanks have no moving parts; they operate totally on pressure. And there is virtually no maintenance; some are even equipped with signaling devices that alert independent vendors when they need to be refilled.

The new system does not need the usual repair associated with oxygen generators, which increases as the machinery ages, and it continues to deliver oxygen even during power failures.

"At a minimum, we're breaking even going to liquid oxygen," said Gary Whelan, who oversees the fish production section, "but when you look at the whole package -- electricity, maintenance and replacement parts -- it puts you ahead. It's a big advantage."

Whelan added the department also can use it to fill the oxygen cylinders on its fish planting trucks.

"That eliminates the need to deal with individual compressed oxygen cylinders," he said. "It saves time, money, reduces injuries and it saves energy."

Sportfishing is a multi-billion-dollar-a-year industry in Michigan. Approximately 40 percent of all recreational fishing relies on stocked fish, including 70 percent of all fishing that occurs for Great Lakes trout and salmon.

To keep this industry going Michigan's fish hatchery system will continue to use significant amounts of energy; there's no other way to raise millions of fish in relatively small spaces.

But DNR fish hatchery personnel have looked, and will continue to look, for ways to make the operation as energy efficient as possible.