Filters

Killer Whale

by Marilyn Hewish

A Killer Whale off Cape Otway

orca

The hobby of bird-watching can lead to all sorts of other interesting observations. At dusk on 20 June 1999, 1 was sea-watching for albatrosses and other seabirds from the cliff-top at Cape Otway. There was a light northerly wind and the sea was fairly flat except for a low swell. I was scanning with a Kowa telescope on a tripod, and I saw something tall, thin and black projecting above the waves.

It seemed to be a fin of some kind. It was to the east of Cape Otway between the cape and Point Franklin from a map I later estimated about 2 km away from me and maybe 1 km out from shore - and very clear in the telescope. The light was still reasonably bright. I thought this fin looked to be large, but wasn't sure because of the distance and lack of other objects for comparison. I watched the fin for about 15-20 minutes, taking notes and making drawings until the light started to fade.

Shape and colour:- In side view, the fin was considerably taller than it was broad, rising almost straight out of the sea at the base, and then slanting gradually so it was bent over slightly at the tip. The trailing edge was concave. The fin was held stiffly upright. From the front, it was held at a slight angle off the vertical, maybe 1 0 degrees. When a wave trough went past it, I could see a short stretch of back on each side at the base of the fin. The colour appeared to be uniform black.

Size:- I was struggling to estimate the size of the fin, until a mollymawk albatross flew past right next to it. The fin height was about half the wingspan of the albatross, which would make it about a metre tall.

Activity:- The fin stayed visible for the entire time at the same level above the sea, and did not sink, or rise. The angle from the vertical was also consistent. It was moving slowly but consistently towards me, and weaving so that I got both front and almost side-on views. It appeared to be a purposeful and deliberate movement.

After I had spent about 1 0 minutes staring at the fin, some flurries of activity started in front and to the sides of it. There were many splashes and areas of disturbed water quite distinct against the flat sea, and sometimes flashes of black bodies within them. At first, the albatross had not passed so I had no idea of the size of the fin and I was thinking it might belong to a large dolphin. I thought these splashes might be made by its companions. However, after I got a clearer idea of size, the fin showed itself to be large, and the .things making the splashes were small animals, their whole bodies being not too much larger than the fin. A few good but brief views of an animal at the top of a leap showed them to be flexible, blunt-nosed and tapering to the tail, and they jumped out of the water and flopped back in rather than 'porpoising'. They were all jumping away from the fin. I came to the conclusion that the fin-bearing creature had drifted into a group of seals which were rushing away out of its path.

Identification:- I had no idea of its identity, except to think it was probably alive (not flotsam) because of the purposeful movement and regular shape, and maybe a whale or large dolphin because of the size. I 'knew' it wasn't a Killer Whale because I had seen them on David Attenborough's TV programmes, with very tall, thin, triangular dorsal fins with straight front and rear edges. The next day I bought a book (Whales and Dolphins of Australia and New Zealand: an Identification Guide, Alan Baker, 3rd ed., 1999; Allen & Unwin, St Leonards, NSW) and saw that Killer Whale fins come in two shapes and sizes depending on the sex of the animal. The only picture in the book that fitted my sighting was the dorsal fin of a female Killer Whale Orcinus orca.

Recently I sent copies of my sketches and notes to Peter Menkhorst of the Victorian Department of Natural Resources and Environment. He agreed with my identification and has entered the observation into the department's wildlife database. The field guide (Baker 1999) describes the female's dorsal fin as shorter (up to 0.9 metres) than the male's (up to 1.8 metres), and slightly. hooked. Killer Whales are cosmopolitan in distribution and common in New Zealand and Australian waters, particularly around Tasmania and along the east coast. Peter Menkhorst told me that there a few sightings of Killer Whales off the Victorian coast each year.

Editor's Note :- In August, 2000, Dale White reported a pod of three Killer Whales close to the shore off Fairhaven Surf Beach. The whales were travelling west, just behind the break where a number of surfers carried on unaware.