Alongside the submarines, ships and airplanes participating in large-scale military exercises in the Pacific this month, teams of sea lions and dolphins are expected to patrol the sea.
These marine animals will be flown in from San Diego for simulated mine recovery and mine detection during the biennial RIMPAC war games.
Six bottle-nosed dolphins would find the mines, while four California sea lions would help recover them.
"There are a number of mechanical systems that work to some degree in those areas, but not as well as the Navy would like them to work," said Tom Lapuzza, spokesman for the Navy's Marine Mammal Program. "Unmanned vehicles are becoming better at finding mines and being able to deal with them, but they are still not as good as the dolphins are."
More than 40 ships, six submarines, 160 aircraft and nearly 19,000 military personnel are taking part in RIMPAC 2006, which runs from Monday through Wednesday.
It brings together military forces from Australia, Britain, Canada, Chile, Peru, Japan, South Korea and the United States for training off Hawaii.
Animal applications debated
The high-tech gadgets deployed by the military can't match the natural skills of the dolphins and sea lions, Lapuzza said.
Sea lions have "incredibly good underwater hearing" and can dive to 1,000 feet (300 meters) to attach a recovery line to a simulated mine, he said. Dolphins use their sonar to find the mines.
"For sure the divers and unmanned vehicles are going," he said. "They are thinking about taking dolphins, but are not sure they are going to do that yet."
Opponents of the program say the military should not train animals for use in warfare.
"These animals are highly sensitive, deeply intelligent creatures, and to use them for warfare is to abuse them," said Wayne Johnson, who is on the board of Animal Rights Hawaii. "These animals need to swim free."
Marine mammals have been used by the Navy since the early 1960s.
The animals save the Navy an estimated $1 million a year, Lapuzza said.
The $15 million Marine Mammal Program has 75 dolphins and 30 sea lions at its San Diego facility.
The four sea lions will be transported to Hawaii in cages with pools of water, and dolphins are carried in 10-foot-long (3-meter-long) fiberglass boxes suspended in a sling and enough water to enable them to float, Lapuzza said.