Near-miss: Leopard seal interference with diver

A member has reported a near miss incident in which diving operations had to be aborted when leopard seals started interfering. The incident occurred during IRM operations on an SPM and PLEM in the South Atlantic. Whilst all divers, equipment and animals were unharmed, the potential risk of harm was very high and could not be ignored.

Leopard Seals are apex marine predators that typically grow to over 3m in length and over 500kg in weight.

In the first instance the animals were displaying a high level of curiosity, showing a gaping mouth and fast circling around the diver. The diver was safely recovered to the LARS basket and brought back to surface as the Leopard Seal got closer and closer. The Leopard Seal continued to remain in the area, beaching itself on the floating hoses, but after a period of no sightings, diving operations were resumed.

A week later the diver was working on the subsea valves when he received a strong push from behind. The diver took refuge between the valves whilst the animal closely investigated the diver, again with high speed swimming and a wide open mouth. The diver was brought back to the LARS basket and recovered to surface but the seal forced the diver to take refuge in the bottom of the basket during the ascent. The diver was badly shaken by the experience.

After consultation with British Antarctic Survey, divers, underwater cameramen and environmental researchers who regularly dive in the South Atlantic and Antarctic waters, the following procedures were put in place:

• A watch for marine mammals should be in place for 30 minutes before starting a dive;
• The marine mammal watch should be maintained throughout diving operations. If a Leopard Seal, or an Orca (killer whale), be seen, this is to be communicated to Dive Control and the diver recovered to deck;
• If the Leopard Seal comes into contact with the diver, the diver is to return as calmly as possible to the LARS basket along the seabed, keeping arms close to the body, and not touching or pushing the animal;
• Midwater swimming is to be avoided when a Leopard Seal is known to be in the area – travel in the basket instead;
• Diving operations should be suspended until 4 hours after the last sighting of the Leopard Seal.