When Craig Swepston wants his athletes to perform, he reaches for a bucket of herring.
Location : San Diego, California
Age : 42
Years on job : 22
As a trainer with the Navy Marine Mammal Programme, Swepston prepares sea lions for military missions. They practise capturing enemy divers with snap-on shackles and locating unarmed mines, dropped by pilots during training missions, so they can be recovered. The creatures can dive more than a hundred metres and recover a target in minutes, he says. “That could take a dive team a week.” In 2003, he spent three months on patrol at Mina Salman pier in Bahrain. “We were the defence against enemy swimmers – think of sea lions as underwater guard dogs.”
Swepston navigates the waters off San Diego in a 10-metre Northwind Marine boat. The craft carries up to four sea lions and holding cages, buckets of fish and practice targets. Away from base, the team uses inflatable Zodiacs.
A 2-metre aluminium cylinder simulates live targets that sea lions – including Joe, left – tag on recovery missions. It’s outfitted with a dual-frequency transponder that emits a 9-kilohertz audio ping detectable by the animal, and a 37-kHz ping, which Swepston tracks himself. “We set the target from 60 metres to 300 metres deep and exercise the animal a number of times on it.”
Sea lions mark the target by attaching a stainless-steel hook (with neoprene bite plate) to a wire loop on the target’s end.
Navy trainers use militaryexclusive defence advanced GPS receivers to set targets at precise points.
Swepston tracks his animals’ location with three devices attached to the harness: a 45-kHz pinger, an RF tag and a satellite tag. “The sea lions rarely stray from the boat, but we can actively track them via satellite if they get lost or disoriented,” he says.