"Congress entrusted NMFS with determining when impacts reach the level of 'significant'" in deciding whether lethal removal should be used to reduce sea lion predation on salmon and steelhead stocks that are listed under the Endangered Species Act, according to documents filed by the federal government in U.S. District.

And the agency used its expertise appropriately in deciding that California sea lions should be removed from below the Columbia River's Bonneville Dam, the documents say.

The U.S. Justice Department filings rebut arguments presented earlier this month by the Humane Society of the United States. The July 3 motion for summary judgment says that NOAA's March decision to allow lethal removal is arbitrary and capricious under the federal Administrative Procedures Act and contrary to the MMPA and the National Environmental Policy Act.

The HSUS motion asks the court to set aside NOAA's decision.

The federal reply filed this week says NOAA followed all the rules in granting 5-year authorization for the states of Idaho, Oregon and Washington to lethally remove California sea lions.

"The Plaintiffs object to the exercise of this 'lethal take' authority on principle," according to the federal filing. "They believe that it should never be used, except as a last resort.

"But that argument has been rejected by Congress, which has weighed the protection of sea lions under the MMPA against the protection of threatened and endangered salmon and steelhead under the ESA, and found that the protection of sea lions must yield under these circumstances.

"While Plaintiffs undoubtedly disagree with this policy, the fact is that NMFS complied with applicable procedures, used its expertise, and reasonably concluded that all of the relevant statutory factors were met. This decision was further supported by virtually every other expert that reviewed the issue," the federal briefs say.

The HSUS arguments focus in great part on MMPA's permitting language that says that lethal removals are allowed only of "individually identifiable pinnipeds which are having a significant negative impact on the decline or recovery of salmonid fishery stocks . . . ." The organization says that NOAA did not prove that the sea lions' impact was significant and didn't properly quantify what sort of impact would be deemed significant.

The federal attorneys say NMFS analyzed three principle factors in deciding whether impacts are significant: (1) whether the sea lion predation is "measurable, growing, and could continue to increase if not addressed," (2) whether the adult salmonid mortality is sufficiently large to have a measurable effect on the numbers of listed adult salmon and steelhead contributing to affect the productivity of the populations; and (3) whether the "mortality rate for listed salmonids [caused by sea lion predation] is comparable to mortality rates from other sources that have led to corrective action under the ESA."

"Applying these factors, the record amply supports NMFS's conclusion that sea lion predation is having a "significant" negative impact under the MMPA," a federal memorandum in support of its motion says.

While the actual observed predation immediately below the dam has reached only as high as 4 percent of the upriver spring chinook salmon run in any given year, the actual level of take is likely much higher.

"Based on the bioenergetic needs of the species, actual take may be as high as 12.6 percent of listed spring Chinook and 22.1 percent of listed steelhead," the memorandum says. In addition, pinniped scarring rates of adult salmon and sea lions rose from 11 percent in 2002 to 37 percent in 2005.

"This level of impact is sufficiently large enough to have a measurable effect on adult salmonid productivity."

That level of impact is "comparable to impacts NMFS has sought to decrease under the ESA. For example, NMFS has reduced the harvest allowed for tribal and commercial fisheries. NMFS has also recommended a series of steps to reduce the impact of the Columbia River power system by incremental improvements," according to the memorandum.

"Plaintiffs repeatedly argue that the impacts of predation are 'at most' 4.2 percent. This is incorrect.

"In addition, Plaintiffs argue that other decisions made by NMFS under NEPA and the ESA make this decision unreasonable. This argument fails because NEPA and the ESA are different statutory schemes with different standards, definitions, and purposes and also because the specific circumstances underlying those decisions make simple comparisons inapt," according to the federal filing.

The HSUS contends that NOAA "reached a conclusion that flies in the face of more than a decade of past administrative decisions concerning the relative significance of those 'other reasons for the decline' of salmonids" as compared to sea lion predation.

But federal attorneys argued HSUS's numbers deliberately downplayed sea lion impact and poorly characterized other sources of mortality. The 17 percent spring chinook impact allowed in tribal and non-tribal fisheries is a maximum and is only permitted in years of abundant returns. And sea lion impacts are more than 4 percent and almost certainly more than the 12.6 percent estimated via the bioenergetics modeling, the federal filing says.

The law requires NMFS to consider those other impacts, which it says it did.

"However, NMFS was not required to eliminate or minimize the impacts of other actions before finding that impacts of California sea lion predation are significant under Section 120 of the MMPA and accordingly, Plaintiffs' argument lacks merit," federal attorneys say.

The states of Oregon and Washington last week both filed motions in support of NOAA, urging that its decision be left in place.

"The threat to the salmon and steelhead in the Columbia River is current and it is significant. The loss of salmonids to CSLs at Bonneville Dam is new and growing. The exercise of this authority poses no threat to the CSL population," according to Oregon's memorandum.

"WDFW agrees with and joins in the motions filed by the National Marine Fisheries Service (NMFS) and the Oregon Department of Fish and Widllife (ODFW), and the arguments in support of those motions," according to the memorandum filed by Washington's Attorney General's office.

"Recovery planning and other efforts to reduce impacts to salmon in the Columbia Basin have been guided by the principle that all manageable sources of salmon mortality should be addressed. This approach is based on recognition that the decline in salmonid populations has many causes, and there is no single action that will restore these fish," the Washington filing says.

"California sea lion predation is currently the only measurable, potentially manageable and yet increasing source of salmon mortality in the Columbia Basin."

Both states stressed that extensive non-lethal deterrence has been attempted, to no avail.

The sea lions typically begin arriving at the dam in the Columbia in winter with their numbers peaking in April and May, the same time that the annual spring chinook salmon spawning run is building.

The federal filings noted that few of the pinnipeds made the 146-mile, inland foray in recent decades past. But their numbers began to swell in 2002, peaking at about 100 in 2004 and 2005.

NOAA in March approved an application via section 120 of the Marine Animal Protection Act that would allow the removal of up to 85 California each year for five years. In its decision NOAA said says it is unlikely that more than 30 could be removed annually.

The decision says that the removals would not harm the health of the sea lion population overall and would reduce mortality of the listed fish.

The plaintiffs now have until Aug. 8 to file their opposition to the federal and state briefs and reply in support of their own request for summary judgment. The briefing in district court would be complete by Aug. 22 when the federal government and states file their replies. Oral arguments are scheduled for Sept. 3.

The district court process was scheduled to allow the judge to render an opinion this fall and thus leave time over the winter for an appeal or appeals to be argued and completed before the sea lions return in force in the late spring.