After three hours of legal debate, U.S. District Court Judge Michael W. Mosman said Wednesday that his "tentative thoughts now" were that NOAA's Fisheries Service had complied with federal law in granting authority for the lethal removal of California sea lions from below the Columbia River's Bonneville Dam.

But at least one issue gave the judge reason to pause -- whether the federal agency had given proper consideration to the impact sea lion removal would have on recreationists that enjoy viewing the large marine mammals.

"This is the point I'm most tentative about," Mosman said at the end of the hearing in Portland.

In its challenge of the NOAA decision, the Humane Society of the United States alleges the federal agency violated the Administrative Procedure Act, the Marine Mammal Protection Act and the National Environmental Policy Act.

A NEPA failing, the HSUS has said, is that "NMFS did not consider the effect of sea lion removal on aesthetic, wildlife-viewing, and other wildlife-dependent recreational interests in this National Landmark and National Scenic area." Nor did NOAA in its March 12 environmental assessment properly weigh the risk posed to Steller sea lions by the proposed shootings of California sea lions that also frequent the area below the dam, HSUS says.

In concluding remarks the judge said he was satisfied the Steller sea lion issue was "given a hard look by the agency."

NEPA requires an EA or a more exhaustive environmental impact statement to determine whether a proposed action will have a significant impact on the human environment. HSUS argues that the proposed sea lion removal deserved a more complete analysis.

Federal attorneys say that kayaking and wildlife viewing were considered in the EA and pointed out that the area where the pinnipeds congregate is off limits to the public. Federal briefs also note that there will undoubtedly still be sea lions below the dam and in the river even after the removal of up to 85 sea lions each year.

Mosman said Wednesday that on most of the points argued his initial thoughts favored the federal decision making. He said he planned to produce a written opinion "in the very near future" but needed time ponder those tentative inclinations. The review of the arguments, applicable case law and writing time would take about two weeks, he said.

A July 3 HSUS summary judgment motion asks the court to set aside NOAA's March decision granting five-year authorization to the states of Idaho, Oregon and Washington to lethally remove California sea lions, which prey on salmon, steelhead and other fishes below the dam and elsewhere in the lower river.

In making the decision, the agency determined that the situation satisfied the MMPA's requirement that only "individually identifiable pinnipeds which are having a significant negative impact on the decline or recovery of salmonid fishery stocks…" can be lethally removed. There are 13 Columbia River basin salmon and steelhead stocks listed under the Endangered Species Act.

HSUS says that NOAA violated the MMPA by failing to properly define in its documents what level of salmon catch by the sea lions represents "a significant negative impact."

Mosman pointed out at several points in the debate that he is "not supposed to dive too deeply into the science." He cited recent precedent established in the U.S. Court of Appeals for the Ninth Circuit that says the science of the expert agency must be heeded.

The opinion in that case said the appellate court had been asked "to act as a panel of scientists," and that "in recent years, our environmental jurisprudence has, at times, shifted away from the appropriate standard of review and could be read to suggest that this court should play such a role."

"We defied well-established law concerning the deference we owe to agencies and their methodological choices," the en banc order said of an earlier decision by a three-member Ninth Circuit panel.

The Ninth Circuit "has some very pointed remarks about what the standard of review is," Mosman said. His task, he said, is to judge whether the decision is grounded in science and rational, and he cannot "pick" the science offered by HSUS over NOAA's unless the organization proves NOAA's choices are irrational.

The judge said Wednesday it is "within the authority and expertise of the agency to attempt to define" what is relatively ambiguous MMPA language regarding significance.

"It's not beautifully written, but I am unable to say it's contrary to the law," Mosman said of NOAA's criteria.

HSUS also argues that NOAA failed to consider other impacts to salmon, as required by the MMPA, and improperly left documents from the administrative record relating to previous ESA decisions allowing harvest and hydro system impacts on listed fish that are greater than sea lion impacts. HSUS attorneys said coming to "no significant impact" or no jeopardy conclusions in prior decisions while finding sea lion take significant is contrary to APA mandates.

Federal attorneys say that "NMFS appropriately considered the effects of the Columbia River power system and fishing on these species in the context of their MMPA decision process," and that NMFS's MMPA Section 120 finding does not "swerve from prior precedents" as HSUS contends.

HSUS attorney Rebecca Judd argued that the NOAA decision is irrational.

"They still haven't explained why 17 percent is not significant" while a sea lion take of 12.6 percent is significant, she said. Judd referred to the maximum allowable harvest of a salmon run. "I don't see any reasonable explanation in the record."

Mosman agreed with federal arguments, saying that the decisions are "made in very different settings" and answer to different statutory demands.

"I don't find the decision here to be arbitrary or capricious or irrational," Mosman said, again qualifying his conclusion as tentative.