14 January 2013

Cuverville Island Landing, Gerlache Strait Killer Whales & Humpbacks, and Port Charcot/Booth Island Landing

Cuverville Island

Cuverville Island

Cuverville Island is the centerpiece in an amphitheater of dramatic steep black spires and near-vertical faces of flowing ice, with tabular and pyramidal icebergs dotting the deep blue water all around. This tall, blocky island sits close up against larger Rongé Island to one side and both are nestled into a mainland bay. Today the peaks were veiled in gradually thinning clouds that eventually revealed stunning blue skies. For me (Kate) it was a painter’s heaven.

For geologists, this was a first look at the formations that make the Gerlache Strait, Le Maire Channel and Neumeyer Channel so famously beautiful. Ian Dalziel explains that the jagged scenery is caused by “the glacial erosion of the Upper Jurassic to Cretaceous rocks of the Antarctic Peninsula Volcanic Group and their underlying plutonic equivalents of the so-called Andean Intrusive Suite. [Over the course of the next three days] we had the opportunity to see several of the intrusive bodies and their relationship to the overlying volcanic rocks.”

At Cuverville Island, people had the option of Zodiac cruising or exploring on land, or both, and both were great. There’s a nice Gentoo Penguin colony at one end of Cuverville’s short beach. Pink krill-colored penguin trails snaked up snowbanks to nests on higher outcrops. This far south, the penguins nest later so the chicks were quite small and wobbly. A few last eggs were even hatching as we watched. Some hikers who apparently have no fear of heights climbed steep scree and snow slopes to outcrops near the top of island. A few inadvertently discovered how skuas behave when a human is near their nest.

Gentoo PenguinsPhoto Credit: Melissa Rider/National Science Foundation

Gentoo Penguins
Photo Credit: Melissa Rider/National Science Foundation

Boaters enjoyed the multifaceted bergs and some were lucky enough to encounter a leopard seal that spent quite some time investigating the boats. A couple minke whales were seen briefly. Zodiacs that circumnavigated Cuverville Island observed a shag colony on the opposite side, and got to see pink and green snowfields where bacteria and algae grow in the ice.

Minke WhalePhoto Credit: Robyn Waserman/National Science Foundation

Minke Whale
Photo Credit: Robyn Waserman/National Science Foundation

It was a lovely, long afternoon ship cruise southward down the famous Gerlache Strait toward our planned evening site at Port Charcot. Conditions were perfect with only a light breeze and no chop. Lookouts were posted on the bridge and it wasn’t long before, voilá, killer whales (orcas) were spotted — and they were harassing three adult humpbacks. The ship slowed to a stop so all could watch. All of us experienced in whale watching agreed that the captain and officers of the watch performed excellent maneuvering, giving us good views while keeping a respectful distance from the animals.

The northwestern opening to the Gerlache Strait near the Antarctic Peninsula.Photo Credit: Peter Rejcek/National Science Foundation

The northwestern opening to the Gerlache Strait near the Antarctic Peninsula.
Photo Credit: Peter Rejcek/National Science Foundation

For nearly half an hour at least twelve killer whales surrounded the much larger humpbacks. The humpbacks slashed their great tails sideways in defense and added powerful vocalizations to their exhalations. The killer whales circled and dove around the humpbacks repeatedly but we never saw any blood. Eventually the killer whales lined up side by side and swam away to other pursuits. We, too, left the humpbacks to collect their wits after what must have been a very frightening encounter.

Humpback WhalePhoto Credit: Tom Hudson

Humpback Whale
Photo Credit: Tom Hudson

Perhaps the orcas had been training the two young calves in their midst. It would be rare for even mammal-hunting killer whales to take down an adult baleen whale; they usually target calves, and these light gray, Gerlache Strait-type killer whales are more commonly known to feed on seals or penguins and fish. Everyone on board with a long camera lens was enlisted to take photographs. These will be shared with the primary Antarctic killer whale researchers, so perhaps our observation will contribute to science’s understanding of these fascinating top predators.

The largest dolphin, Orcas can grow to nearly 10 meters in length and to 7 tons in weight.Photo Credit: Joe Stanford/National Science Foundation

The largest dolphin, Orcas can grow to nearly 10 meters in length and to 7 tons in weight.
Photo Credit: Joe Stanford/National Science Foundation

Other small groups of killer whales were seen both before and after this amazing interaction. A little while after, three killer whales appeared and dove right alongside the bow of the ship, to the delight of everyone out on the front deck. The captain again circled the ship, perhaps hoping to get his own photos; however, the hunters, apparently uninterested in the Akademik Ioffe, disappeared in our wake.

Port Charcot is a bay on the west side of Booth Island, which forms the west side of the narrow Lemaire Channel. This would be our southernmost landing and Zodiac cruising spot. With the unending sunset at this high latitude, people could choose landing or cruising from about 8 p.m. to midnight. The clouds had closed in but the light was still lovely in pale shades of peach and lavender.

Booth Island

Booth Island

The Zodiac cruising was terrific, with a gorgeous arch in one huge berg, minke whales interacting with boats, and leopard seals getting curious. Cheesemans’ staff member Michael Moore captured some impressive underwater video, using a GoPro camera mounted on a pole, of a swimming leopard seal. These huge predators live on penguins and krill. They are renowned for their enormous gape and powerful jaws that deserve respect. Any close encounter where one looks you in the eye leaves an indelible impression of having met someone who sees right through you.

A leopard seal captures a Gentoo penguinPhoto Credit: Sean Bonnette/National Science Foundation

A leopard seal captures a Gentoo penguin
Photo Credit: Sean Bonnette/National Science Foundation

On Booth Island, an easy walk across from the tiny landing beach gave views of the “iceberg graveyard” on the other side, where innumerable islets and shallow rocks trap bergs drifting in from farther south and west until they melt, sometimes years later. Five leopard seals were hauled out on ice chunks near the shore. Tim Carr led a hike onto a shoulder overlooking this scene, where they could hear the haunting calls of the leopard seals. In South Georgia these forlorn sounds were once mistaken by whalers for the horn of a freight ship.

Photo Credit: Tom Hudson

Photo Credit: Tom Hudson

Of course the Gentoos and Adélies nesting around near the landing were quite delightful, though they were getting sleepy in the late hours, only occasionally stirring to check on their recently hatched tiny chicks. There were great views of the wide ocean if one climbed to the rock cairn monument to explorer Charcot, up on the small ridge beside the landing. It was accessible by either an easy walk up a gentle snow slope or by scrambling up rock directly from the landing. Of course most of the geologists took the rocky way.

An unusually good assortment of Antarctic bird nests were very near the landing. The rock-climbing geologizers encountered a very protective pair of Antarctic Terns. Two tall, fluffy, still-flightless Kelp Gull chicks were guarded by their fearless parents on a low boulder. The diminutive Wilson’s Storm-petrels appeared in growing numbers as the light faded. They were coming in from a day’s foraging at sea to return to their scree-slope burrows. They are as acrobatic in flight as swallows, both over the waves where they dance against the surface pattering their webbed feet to bring up crustaceans, and as they flit tirelessly back and forth across the cliff faces near their nests before they land.

Wilson's Storm-Petrel

Wilson’s Storm-Petrel

All were back aboard ship at midnight. Though the sun had set at 11:30, it was not even dark at 1:40 a.m. when I went to sleep, and the sun would be rising again in less than an hour. The darkest minutes were brighter than twilight: one could see the different blues in the icebergs slipping by, and if there had been a whale nearby one could have seen it clearly. Somewhere out there, the leopard seals snoozing on their floating ice beds were just as cozy in their blubber-and-fur coats as we were in our fluffy duvets.

Midnight SunPhoto Credit: Tom Hudson

Midnight Sun
Photo Credit: Tom Hudson

- Kate Spencer, Staff Naturalist; Cheesemans’ Ecology Safaris