From Phillip Island & District Historical society general meeting minutes, April 2010
Guest Speaker:
Roger Kirkwood is the Mammal Biologist at the Phillip Island Nature Park with a background in fisheries research and Antarctic research on penguins. He has written two children’s books: Antarctica and The Emperor’s Kingdom: Living on the Ice. He studies the seals at Victorian islands, including Seal Rocks off Point Grant.
The fur seals of Seal Rocks are very like sea lions in that they are large, have the odour of sea lions, are thigmotactic (like to touch) and are benthic (bottom) feeders, but are typical of fur seals in that they have two layers of fur.
Seals appeared in Australian waters 3-6 million years ago, with the Seal Rocks species artocephelus pusillus doriferus arriving 18-12 thousand years ago. Fourteen thousand years ago Bass Strait did not exist and what is now Seal Rocks was a distance inland. However, seals were in the area and it is believed Aborigines hunted them for their blubber and skins, which are extremely warm.
While Grant is credited with discovering Bass Strait in 1800 there was shipping in the area prior to him, as proved by the grounding of the Sydney Cove at Preservation Island in the Furneaux group in 1797. Seal Rocks was seen by Grant in the Lady Nelson covered by seals in March 1801.
In Sep 1801 Robert Campbell and his crew in the Harrington took 3000 skins and 2500 gallons of oil. By 1826 there were 2+ sealers on Phillip Island taking 1000 skins annually from Seal Rocks. Seven sealers were operating in the 1840s, and in 1860 a boatload of skins is recorded to have been taken, with males being hunted for their reproductive organs.
The seal trade was enormously important to Australia in the first half of the 19th century, with a ‘seal rush’ stimulating a ship building industry and seal fur felt hat industry. Australia ‘rode on the seals’ back’ before whaling. Between 1800-1810 130,000 skins were taken, but by 1830 it was down to 20,000 with virtually none left by 1860.
Sealing ceased on Seal Rocks in 1923, but was followed by a couple of culls by fishermen in 1934 and 1948 when up to 600 were shot. Seal Rocks became a State Faunal Reserve in 1975 and came under the Commonwealth Wildlife Act in 1975.
Taxonomy of the fur seals was very confused, beginning in 1802 with Baudin and not being clarified until 1971 by Repening and others.
Roger showed slides of old engravings and photos of sealing activity in Western Port and of seals and naturalists at Seal Rocks in the early twentieth century.
Research began there with Le Soeuf in 1925. In 1945 Fred Lewis from the Fisheries and Wildlife Division did counts and examined stomach contents. The really big research program was by Bob Warneke and his crew from F&WL between 1966-1991. They did counts, tagged pups’ flippers, examined stomach contents, determined causes of death and recorded behaviour.
Roger showed slides of the research buildings, the flying fox between the main island and Black Rock, and the stone hut on east beach at the base of the main plateau, built in 1979. From 1997-the present the Phillip Island Nature Park has also carried on an extensive research program, doing counts, analysing scats for diet, tracking seals for their foraging range and diving behaviour, looking at human interactions with the seals, and also doing hut maintenance.
There are 20 seal colonies in southern Australian waters: in Victoria, Tasmania, NSW and SA, with a total pup population of 21,882 in 2007. Victoria had 78% of the pups.
Part of Roger’s job is to disentangle seals that have become trapped in human cast-offs, such as trawl and other netting, box strap, twine, plastic bags, rope, etc. He showed slides of the technique he uses to crawl on his stomach with a large net until close enough to the entangled seal to trap it in the net.
Roger also explained the seal tracking program which so far has included 25 juveniles, 13 adult females and 11 adult males. They stay on the Continental Shelf and mainly in Bass Strait and west and east coasts of Victoria. Some venture into NSW.
Diet has been recorded near monthly for 10 years from scat contents (fish bones, etc). Mostly the seals feed on redbait and jack mackerel, but also gurnard, red cod, barracouta, leather jacket and squid, depending on factors such as upwellings and currents.
Bruce Procter gave the vote of thanks for Roger’s fascinating and informative talk, mentioning that Roger had enlightened us as to how financially important the sealing industry had been to Australia.