A federal judge has dismissed a lawsuit challenging the Navy's use of sonar in Hawaii waters.

The court says an environmental study and other developments have rendered the case moot.

Earthjustice filed the lawsuit against the Navy in May 2007 on behalf of the Ocean Mammal Institute and other organizations.

They lawsuit argued sailors should do more to protect whales and other marine mammals from Navy sonar.

Both sides in the dispute asked U.S. District Judge David Alan Ezra to dismiss the case.

U.S. Pacific Fleet spokesman Mark Matsunaga says the Navy's recent completion of an environmental study for its Hawai'i training area was one factor that rendered the case moot.

The dismissal Wednesday also dissolves an injunction Ezra imposed restricting the Navy's use of sonar.