Every year, month, week, and day in Antarctica is different. From year to year the whole timbre of the landscape can change with the ice conditions. From day to day the weather can turn on a dime and turn a peaceful and tranquil vista into a dark and wind-battered curtain of snow. Through it all, the animals that make this place home weather the storm and we must do the same.
Working with whales requires an ingredient list that would rival a witches brew. We need to have whales, whales behaving in a manner that allows us to get close to them, daylight, calm seas, little wind, a platform to work from, etc. When these things all line up we have to be ready to take advantage of the time and work efficiently. Once these elements come together we focus our efforts.
This morning, we have calm seas, fair winds and a glorious display of morning light filling the sky at 4 am. The horizon is peppered with the blows of humpback whales, the 20 foot-tall columns of vaporized water hanging above the sea for a few seconds offers evidence of where the whales were. At least 15-20 on a quick scan from the bridge of the ship. This is the perfect opportunity for us to work. I prepare our biopsy gear, satellite and suction cup tags and assemble the team for an early morning on the water. We talk about our goals; we would like to deploy a multi-sensor suction cup recording tag to understand the fine-scale movement and foraging patterns of the whales for 24 hours, deploy a long-term satellite tag that will show us the movement patterns of the animal throughout the entire feeding season, and collect a number of biopsy samples that will elucidate the population from which these whales came as well as if they are male or female.
From the small inflatable boat, I direct the driver from a pulpit that sits above the pontoons and always be a slightly higher view from which to see the whales and a platform to lean out just enough to tag the animals. We find a number of animals bubble-net feeding, creating spiraling circles of bubbles underwater to concentrate or aggregate the krill and then lunging up through the center with mouths agape to feed on the small crustaceans. When the whales do this, it is obvious where they are likely to come up and once they do, they are trapped at the surface for half a minute while they sift all of the water out of their mouths before going down once again for another foraging bout. We slowly approach a bubble net as it forms at the surface and when the whales come up, we idle in their direction. I communicate with the driver where the whales are and where we need to position ourselves to place the suction cup tag on the whale’s back. When it arches to dive, the whale shows us a fine piece of real estate and with a gentle thwack, I place the tag on the whale. The tag sits at the end of a 25-ft carbon fiber pole that looks like a giant magic wand and it does not take much effort to place the tag on. As soon as the tag is deployed my graduate student collects a small skin and blubber biopsy sample using a crossbow and customized tip that takes a small sample about the size of a pencil eraser.
Once the tag is deployed we can listen for it with a VHF antenna and receiver. Whenever the tag is above the surface (either on the whale or once it has fallen off and floats) we hear a signal and can keep track of the whale’s location. We spend the rest of the morning following the blows in the early morning air and collecting biopsy samples. The tag will stay on the whale for about 24 hours and then fall off. When it does, we use the tracking gear to locate it and retrieve it. The data are stored on the tag so we have to get it back in order to get the data. When we do it is a flurry of downloading, running code, and generating figures. Our tag is out now, on a humpback whale maneuvering through the icy depths. When we retrieve it, we will see the motion of the whale, count how many times, where, and when it feeds and how these massive ocean giants make a living in the Antarctic.