The Chesapeake has been certified as sturgeon safe—at least if the region meets its goals to clean up the Bay’s water.

The National Oceanic and Atmospheric Administration’s Marine Fisheries Service this spring issued its official “biological opinion” that new Chesapeake water quality criteria published by the EPA last year would not likely harm the recovery of the endangered shortnose sturgeon.

The approval is significant because it means that states can move forward with adopting the criteria for dissolved oxygen, chlorophyll a (a measure of algae) and water clarity as enforceable state water quality standards without worrying that their actions could violate the federal Endangered Species Act.

Rich Batiuk, associate director for science with the EPA’s Bay Program Office, said the approval was validation that “good solid science went into the criteria.”

He noted that some of the dissolved oxygen criteria were set specifically to protect sturgeon, using information from recent studies about the effects of temperature and dissolved oxygen on the fish.

The criteria would be protective of all of the sturgeon’s life stages except in the deepest areas of the Bay which naturally have low-oxygen conditions in the summer.

“We are not impacting the organism,” Batiuk said. “In fact we are going to be benefiting its recovery by increasing the amount of suitable habitat available to sturgeon.”

The Bay Program in April 2003 completed a three-year process of developing complex new water quality criteria for the Bay. Part of the criteria set minimum levels of dissolved oxygen needed in different parts of the Bay to protect the aquatic life that uses those areas.

Sturgeon, though, are less tolerant of low oxygen than most other fish. They are also sensitive to warm temperatures, so during the summer they are often squeezed out of both surface areas because of high temperatures, and deep areas because of low dissolved oxygen.

To deal with that problem, the Bay’s criteria requires that warmer water have more oxygen than cooler water to reduce stress on the fish.

The new water quality criteria were published by the EPA last year to guide the development of enforceable water quality standards in the four Bay jurisdictions with tidal waters—Virginia, Maryland, Delaware and the District of Columbia.

To attain the water quality criteria, the Bay Program estimates that the amount of nitrogen entering the Chesapeake from its 64,000-square-mile watershed must be slashed 48 percent from mid-1980s levels, and phosphorus by 53 percent.

But NOAA, which has the responsibility for protecting the endangered shortnose sturgeon, had questioned whether the criteria were protective enough, and initiated a formal review last year.

The issue was critical to the Bay because NOAA could have required changes in the criteria—possibly requiring further cleanup actions — if it had determined they were not adequate to protect shortnose sturgeon.

This spring, though, NOAA biologists issued their formal opinion stating that some deep parts of the Bay would have “suboptimal” oxygen conditions during the summer, but any adverse impacts of the fish would be short term and not lethal.

Overall, NOAA said achieving the criteria would “result in significantly improved water quality conditions in the Bay, elimination of anoxic zones and the improvement in the quality and quantity of habitat available to shortnose sturgeon as well as improving the chances for shortnose sturgeon recovery in the Bay and improving the likelihood of long-term sustainability of this population.”

The opinion does require the EPA to submit a report to NOAA each year summarizing the progress in achieving nutrient reductions and summarizing water quality conditions from the previous year. And it leaves the door open for additional action if the water quality goals are not met in 2010.

Under the Endangered Species Act, NOAA has to review any federal action that could affect an endangered species. That means not only did the agency have to review the criteria, it will review the EPA’s approval of all state water quality standards based on the criteria.

Batiuk said that as long as the state standards adhere to the criteria affecting sturgeon, NOAA has agreed a stepped-up review process.

While the biological opinion does not deal with Atlantic sturgeon, which are not protected under the Endangered Species Act, Batiuk said the criteria should be equally protective as its water quality requirements are nearly identical to those of shortnose sturgeon.

“They have about the same sensitivities,” Batiuk said. “We looked at juveniles and adults, so we considered several life stages.”

Interest is growing among many state and federal fisheries biologists in launching an effort to rebuild Atlantic sturgeon populations in the Chesapeake.

Sturgeon were once abundant in the Chesapeake, but they were the target of intense fishing pressure a century ago, which depleted the population of both Atlantic and shortnose sturgeons. Neither population has significantly recovered in the Bay.