Icebergs And Orca

On 15th December, we passed 60° south which officially means that we are in Antarctica! The day unfolded like no other on board - whilst climbing up onto Monkey Island, I caught a glimpse of dorsal fins in my peripheral vision. As I hurried onto the deck, Ryan had already spotted a male orca, two females and then.... a calf surfaced right next to its mother. The group were so close to the boat that we could see them perfectly. 

Orca, Orchinus orca, are a species with a cosmopolitan distribution. Within the orca species, different ecotypes have been identified according to ocean basins ie. North Atlantic ecotypes, North Pacific and Antarctic. Ecotypes arise due to evolutionary processes which generate genetically distinct populations that can no longer interbreed. Orca ecotypes often look different, prey upon different food sources, maintain geographically distinct ranges and even adopt different vocal communication. When implementing conservation measures for marine ecosystems, the most effective practices will recognise different ecotypes and adopt species-specific management. The orca we sighted at 60° south were Antarctica 'Type A ', we were able to determine this using distinguishable features such as the size of their eye patch, the shape of the saddle patch and other markings on their back. Type A Antarctica orca are distributed in offshore, ice-free open water. As we approach the peninsula and travel into inshore waters with dense pack ice, we expect to encounter Type B orca.

The shape of the white saddle patch photographed here is a key identifiable feature which allows us to distinguish between different Antarctic orca ecotypes.

The day continued to become more 'Antarctic' as icebergs emerged through the fog on the horizon. At first, I could just make out their outline but within the hour, distinct forms stood proud and offered much variation to our seascape. I have become very accustomed to looking out onto vast expanses of ocean, so much so that when I watch a film with forests, I'm almost shocked as if I've completely lost touch with terrestrial land!

The seascape dramatically shifted from vast expanses of open ocean into an iceberg field

The ship took a wide berth around Coronation Island (the largest of the South Orkney Islands) to avoid the icebergs that had grounded on the very shallow plateau surrounding the island. Soon after, we caught our first glimpses of Antarctic land amongst the icebergs. In addition to the stations on King Edward Point and Bird Island, which I wrote about in my last blog, the third base on our route is Signy. Signy is a 6.5 km long island and is located south of Coronation Island. We arrived into the bay late afternoon and Ryan and I could not keep track of the whale sightings. Left, right and centre, humpback whales were surfacing and giving us spectacular fluke (tail) displays before diving again. We also encountered fin whales in the bay displaying proud, tall columnar blows. Gentoo, chinstrap and Adelie penguins were darting out of the water around the ship whilst others were spotted on icebergs before they plunged into the ice-cold water. The ships sensors were recording temperatures of -0.5°C. This was the Antarctic experience I had dreamt of. And if seeing whales wasn't special enough, sighting them against a backdrop of sheer ice cliffs blew me away. Almost all BAS staff (35 of us) were up on Monkey Island gaping in awe at the spectacle unfolding in front of us. We realised then just how lucky we are. 

Humpback whale fluke - Signy Island

 Adelie penguins darting out of the water

An Adelie penguin on an iceberg

View from the ship - on the approach to Signy

Despite the perfect weather conditions we experienced upon arriving into the bay, our landing onto Signy Island the following day was delayed due to bad weather which prevented the cargo tender going ashore. Similarly to Bird Island, Signy is such a small station that is does not have a substantial enough wharf to harbour the JCR. Therefore, the crew organised shuttle runs between the JCR and the island. It was crucial that an inventory was maintained to keep track of the many cargo pieces so that once items were located from the hold, their number could be called out and ticked off from the ship and then again on the wharf at Signy. It wouldn't be very amusing if certain items of cargo were missed off eg. toilet paper.... or more serious scientific equipment! 

Half of the team spent the day unpacking new mattresses, making beds and organising the food stores, whilst the tech service team were busy turning the generators on, cleaning the reverse osmosis plant (to obtain drinking water) and starting up communication systems. Signy is a summer only station and therefore everything had to be in working order before the JCR left the station. I couldn't help thinking how it must feel to be one of the four summer personnel on station waving goodbye to the JCR for 8 weeks, knowing that they would be the only ones on the island. 

                                        Transporting drinking water reserves onto the station 

Boarding the cargo tender

Through assisting the station relief, I have certainly gained an appreciation for the work it takes to keep a BAS station running, from the ordering of cargo, to packing in a warehouse, to stowing on a ship in a way that preserves the items, to the final relief at each research station.

 

A brown skua

We were lucky enough to be taken around the island with the field guides and explore the sites. After a walk crossing mossy vegetation and patches of ice, we came across 4 Adelie penguins waddling towards their colony. Together with emperor penguins, Adelie penguins are the most southerly distributed penguin species and we also expect to have these visitors at Rothera. 

As we continued to climb, a spectacularly grand Adelie colony unfolded beneath our eyes. This was the kind of footage you see on TV: hundreds of thousands of penguins tightly packed together in circular colonies. Skua birds were making attempts to dive for the Adelie chicks and as I took a closer look through my binoculars to see the chaos, the skuas had been successful. Adelie penguins are intriguing individuals; small black and white birds with afro style haircuts. They are extremely inquisitive and are not shy to make themselves heard! Adelie penguins build nests using stones and lay two eggs. The eggs are incubated for a month with both parents assuming equal responsibilities in the form of 12 hour shifts.  

                                                                 

                                                      Adelie penguins wandering past

An Adelie rookery

I was delighted to have my first sighting of chinstrap penguins. While also black and white, chinstraps are distinguished by a distinctive black line under their chin - hence their name. Chinstrap penguins are the most abundant of the Antarctic penguins.

                                                                   

                                                                   Chinstrap penguins

As the tour continued, we passed crabeater seals inhabiting the tops of icebergs and Weddell seals laying on the beach. We took a route to the Cemetery Flats where piles of elephant seals were laying on top of each other to stay warm. It was delightful except from the repetitive farting and burping which regularly erupted from the seals! Cemetery Flats are a relic of past whaling on the island. The low lying beaches are littered with fossilised whale bones. Amongst the plains (abandoned whaling grounds) are five graves from the whaling days, a stark reminder of what was once a terribly dangerous and destructive profession. I was confronted by the thought that although whaling is an activity of the past, today's destructive fishing practices vividly mirror the depletion of whale stocks in the 1980s.

A dozing Weddell seal

A resting elephant seal 

Elephant seals 

I highly recommend Britain's Whale Hunters - a fantastic BBC documentary exploring the stories of whalers and focusing on Antarctic whaling stations.

Ryan (Marine Assistant) and myself on Signy beach admiring whale vertebrae that have become petrified