While I don't predict outcomes based on the types of questions asked, a New York Times editorial on the case opined that "[s]ome of the justices’ comments this week sounded as though they were feeling far too deferential to the military." Law.com's take was "that most justices seemed to accept the Bush administration's argument that the needs of the military should trump environmental concerns about damage to marine mammals." A slightly more optimistic L.A. Times report stated that the justices sounded closely split on the case.
A separate NY Times article mentioned a dubious Hobson's choice offered by the Chief Justice that seemed to imply that the judge below needed to choose between protecting dwindling marine life populations and North Korea attacking Hawaii:
My question, though, is that at no point that did the district judge undertake a balancing of the equities, putting on the one side the potential for harm to marine mammals that she found -- and that's your point about the record -- and putting on the other side the potential that a North Korean diesel electric submarine will get within range of Pearl Harbor undetected. Now, I think that's a pretty clear balance.NRDC's attorney pointed out that the trial judge, who heard all the testimony and evidence presented by the Navy and NRDC, made a factual finding that the Navy's training would not be impacted by the decision to have limits on the use of sonar.