This week at the station
This week at Macquarie Island: 29 November 2013
Elephant seal Life
It was around the 7th September, (the day of the Federal election) that the first elephant seal pup was seen on the beach on the western side of the isthmus. The pups are around 40kg at birth. Everyone was so excited, with many heading out to the beach to get glimpses and photos of that seal pup.
Just the week before, on the 3rd, we had started the elephant seal census. Every Sunday, until the 17th November a count was made of all the female elephant seals on the beaches around the isthmus and beyond. On the western side the count was made from the northern most harem (known) of Camp Beach, just below Wireless Hill, right next to the station, all the way down the beach to the rocks at the corner then along West Beach to the jump-up to the West Coast featherbed.
The eastern side started at Garden Cove and then the beaches to the south of Camp Hill to Tractor Rock.
Each side was split into harems, which were known from past counts.
On that first count there were four seals (females) on the eastern side and 6 on the western side, none with pups. The second week, 8th September, the count was similar with 3 in the east and 7 in the west. This time however, there were two pups.
The numbers increased exponentially over the next six weeks peaking at 872 on the eastern side and 1883 on the western side, for a grand total of 2755. The largest harem was at Razorback West which had around 700 females.
Each harem had one male dominant male ‘beach master’, who was always fighting off challengers from every direction. It seemed that at the larger harems the beach master tolerated several other large males who looked after the periphery of the harem.
Added to this was the large number of pups. We never counted the pups but it seemed that most of the females in the harems did give birth. On one occasion while walking along the western beaches I saw 3 births in a 15-minute period.
At the peak the noises were incredible, with pups and females constantly barking in the closely packed harems. There was the occasional roar of the big bulls warding off challengers. Of course there were numerous battles for supremacy and an occasional overthrow of a beach master. Most of these battles were brutal affairs, with one resulting in the death of one of the protagonists.
Pups start to wean and become independent from their mothers after around 21 days. At this time they are 120 to 130kg, a weight gain of 80 to 90kg in three weeks.
By the 17th of November the number of females had dropped to a total of 131. It was hard to distinguish between females who had given birth or males and females who were coming in to moult. Counting the moulting seals will be the subject of the next census.
At the moment the beaches, tussock and any spaces around station are occupied by weaners and moulting seals.
Barend (Barry) Becker