Preventing whale beaching

It was reported in 1995 that the New Zealand's Department of Conservation was looking at two lines of research for directing pilot whales away from potential stranding areas. In January, a bubble net or "air curtain" was used for the first time in Golden Bay. This comprised air compressors and a perforated hose which was draped two or three metres below the surface. The bubble "wall" acted as a barrier and reflected the whales sonar back to them. It had reasonable success in turning whales at sea, but once the whales discovered the wall was an illusion then its effectiveness was reduced. It was a mixed success, possibly useful as a short-term measure. In future the bubble net is likely to be most effective in herding refloated whales out to sea after a stranding. The second avenue that DoC was investigating was to use the same mechanism that draws so many whales onto the shore in the first place - the animal's own distress signals. DoC was hoping to record pilot whale distress calls and use the recordings to attract refloated whales away from danger areas.

It has been suggested that if some sort of human chain could be put between a sick whale and its pod, this would prevent the healthy whales beaching. While it has sometimes been possible, using this method, to prevent restranding once a pod has been put back to sea, it is very difficult to carry out beforehand because of the difficulty in identifying the sick animal and the logistical problems of having enough people on the spot at the right time.

Some whale rescuers suggest that if the leader of a pod is put to sea then the other whales will follow. The problem here is that it is usually impossible to read the social dynamics of any pod. As pilot whales are socially matriarchal, the leader will usually be female, but it is very difficult to identify the leader of a pod. There may be more than one, the pod may have a number of subgroups within it, and the leader will not necessarily be at the front.

Perhaps a tape recording of orca feeding might deter pilot whales from entering the bay. Buoys supporting speakers and underwater equipment, he says, could be placed across the entrance, and a solar panel and unit could pick up the sound of the approaching pilot whales and turn on the tape. Opinion is divided whether this would work or not. Some conservation managers believe it is akin to throwing a stoat in amongst a group of chickens, and could well panic the whales, while others say it is a natural sound that pilot whales would recognise and avoid. Use of such deterrent noises has been largely unsuccessful worldwide.