Humpback whale Photo: Frank Grebstad
Preparing to travel and do research in Antarctica is unique. It is a combination of finding the right equipment to keep warm and dry yet flexible and mobile and all of the scientific gear that is needed to accomplish your research. The preparations start months in advance looking at data from the previous year; where did the ship go, what were the conditions like, where were the whales most abundant, where did they spend the most time once tagged. This information is critical to think about how to maximize the precious little time we have to deploy our instruments and collect samples.
Our main objectives are to locate humpback whales early on in the feeding season and deploy satellite-linked tags that will provide us with positions of where the whale is nearly every time it comes to the surface during the season. The tags transmit a signal that is received by orbiting satellites and triangulate the location of the whale and send that information to a web site where we can log in and see all of the positions as they are acquired. We use this information to study the different behavioral states of the whales and can determine when and where whales are foraging. If you think about whales searching for patches of krill and then when they find a good area, remaining in it to feed, the track of the whale will have very distinct shapes. Whales that are transiting will generally move in one direction with little change in course from one position to the next. However, when whales are feeding in what is called ‘area-restricted search’ the turning angles between locations will be variable and the whale will generally stay in the same location for a given period of time. We can use a number of analytical tools to determine when, where, and for how long each of these foraging bouts takes place and then link these in space and time with environmental co-variates like water depth, distance to the ice, known distributions of Antarctic krill, historic catches from the commercial krill fishery etc.
We will also collect a small skin and blubber sample from each whale that we tag (as well as from other whales that we encounter) that will allow us to determine the sex of the whale, if a female if it is pregnant or not, what the whale has been eating, and what breeding population that whale comes from. All of these demographic pieces of information are critical to understand how animals behave during the feeding season and where they forage.
A couple of weeks before departing, we will look at images showing the distribution of sea ice which will dictate where we can and cannot work, and try to locate known areas that are likely to have whales early in the feeding season; these are generally open water areas near the ice edge and often close to shore. Much of our equipment remains in a warehouse in South America to be placed on our research ship in advance of our flying down. This includes our biopsy sampling equipment including crossbows and customized bolts with a small float on the end and a hollow tip about the size of a pen cap that collects the sample from the whale. The satellite tags are deployed using a modified line launching mechanism using compressed air to discharge the tag. The tags themselves anchor in the skin and blubber of the whale and have a small antenna that is programmed to transmit a signal every time it is out of the water until the battery is exhausted several months later. We leave this gear at the port of departure to minimize the amount of gear we have to travel with otherwise. Jackets, waterproof pants and boots, base layers, hat, gloves, sunglasses, computers, cameras, GPS, and all of the related accessories add up! Suffice it to say, we tip the scales at the airport and push the limits of what we are allowed to carry and check on for baggage!
The trip down is long and arduous. It takes a full 24 hours to fly from the US to southern Chile or Argentina, including an overnight flight to either Santiago or Buenos Aires. Once we arrive at the southernmost points of South America in Punta Arenas, Chile or Ushuaia, Argentina, we spend a day loading our cargo on to the ship and then it is a 3-5 day journey across the Drake Passage and to the icy waters surrounding the Antarctic Peninsula where whales and krill and sea ice and glaciers help provide the most amazing and inspiring ecosystem on the planet. We are lucky to be here and even more fortunate to be able to call this place home for the next few months.