Author: Sue Gibbs
Office for Coast and Marine, National Parks and Wildlife, SA
Each winter Southern Right whales migrate north from their sub-Antarctic feeding areas into warmer waters to find mates and to calve. The base of the spectacular cliffs, in the Great Australian Bight Marine Park, South Australia is one location where many of these great whales gather. The 2001 winter was no exception with more than 120 sighted since the first arrivals in May.
On 2 July a young adult arrived at the Head of Bight with rope and a buoy tangled around her tail. National Parks and Wildlife, SA (NPWSA) quickly sought advice from around Australia to assess if it was possible to remove the entanglement from the whale – 14 metres long and 50 tonnes in weight. Advice and offers of help were generously forthcoming while news footage and aerial photographs were examined. The South Australian Research and Development Institute (SARDI) research vessel, Ngerin was made available to assist and a team from the Western Australian Department of Conservation and Land Management, with experience in disentangling whales, was willing to help. Equipment was located and purchased from Quinn Marine, and a satellite tag designed for tracking elephant seals was kindly loaned by the sub-Antarctic Division of CSIRO, based in Tasmania.
Soon plans for disentangling the whale took shape. A mammoth task, involving a remote, almost inaccessible location, rough seas and many sharks. The entangled whale was in a nursery area of the whale sanctuary amongst others with newborn calves. The consequences of disturbance to cows and calves were considered.
Careful preparation was needed, the nearest hospital being several hours flight by helicopter away, we could not afford accidents. This rescue was made especially hazardous as the entanglement was around the whale’s very powerful tail. Further danger came from sharks following the stricken whale. Near perfect weather conditions were required to even attempt the difficult rescue while minimising risk to rescuers, and the weather was not on our side. Forecasts indicated wind speed would drop to less than 10 knots the following Tuesday and Wednesday and the rescue attempt was scheduled for this window of opportunity. Meanwhile, the whale was monitored from the cliffs and by aerial surveillance. After that two-day window, long range forecasts indicated impossible weather for the next five to ten days.
Saturday morning, as the Ngerin was preparing to leave Adelaide for the sixty-hour journey to the Head of Bight, we received news from a spotter plane crew that two sharks had been seen very close to the whale. A second spotter plane sent up Saturday afternoon, found her floating motionless on her side with up to eight sharks (one white pointer reported to be five meters long) feeding on the body. The buoy was no longer attached, although the rope was.
As whale, seal and sea lion numbers increase concurrently with human use of the oceans, linked with the use of new, stronger and longer lasting marine gear, entanglements are likely to occur more frequently. NPWSA now has the equipment to deal with marine mammal entanglements and has planned workshops for training staff in its safe and appropriate use. A response team with a strategic plan will be put in place.
The Great Australian Bight Marine Park is closed to fishing each year prior to the arrival of the whales. Inspection of video footage of the buoy suggested that it did not come from the local fishing industry. The whale may have picked it up anywhere on its journey from the sub-Antarctic to the Head of Bight.
The Southern Right whale skeleton was retrieved by the SA Museum and will become part of their permanent collection.
NPWSA thanks SARDI, CALM, especially Doug Coughran and his team, the CSIRO Sub-Antarctic Division, especially Nick Gales for their generous advice and assistance and the numerous other individuals and organisations involved. These include (in no particular order):
- Environment Australia
- The South Australian Police
- Transport SA
- Channel Seven News
- PIRSA, especially Fisheries SA
- The Ceduna Hospital
- Royal Flying Doctor Service
- The people of the Yalata community
- The Port Lincoln Dive School
And everybody else who was involved – you know who you are. The cooperation and generosity of spirit you demonstrated was incredible.