As I watch the slate gray waves moving rhythmically away from the bow of the vessel, a shocking white cloud erupts ahead of my field of vision. My eyes, momentarily blurry from the hypnotic motion of the waves, focus on the spot where the white anomaly appeared. Again, a spout appears, stark white against the ashen sky and sea. ‘Whale’ I whisper with enthusiasm, trying not to annoy the crew who are busy driving the ship. This is not the first whale I have seen, in life or on this trip, but after hours of scanning the waves, the sight of a whale’s ‘blow’ is a welcome jolt. Such is the day-to-day life of a marine mammal observer on a research vessel.
On an interdisciplinary research expedition, such as the Arctic Shelf Growth Advection Respiration and Deposition project (ASGARD), the overall role of the marine mammal observer (MMO) is to connect the observations and data collected by the physical, chemical, and biological oceanographers to the upper trophic organisms, the top of the food chain. In many ways, marine mammal and seabird observers are the ‘eyes’ of the science team. Not only do we observe and count the seals, whales, and birds that come into view on the transects, but we also note weather conditions, dead animals, and marine debris that we see along the way. Sadly, there have been some days during the cruise that I counted more trash floating by than animals. One of the moorings, a chain of oceanographic instruments anchored to the sea floor, that we recovered had a plastic bag wrapped around its chain. Plastic pollution, which is plaguing our world’s oceans, has made its way into the Arctic.
One of the unique aspects of working as a MMO on the ASGARD cruise is that not only do I collect visual observations of marine mammals from the bridge, I can also ‘listen in’ on them using underwater microphones, called hydrophones. Part of the ASGARD project is to deploy hydrophones at three locations in the northern Bering Sea. The hydrophones will turn on every hour and record the first 25 minutes of that hour, capturing any vocalizing marine mammals and other marine life in the area. Since this is the second year of the project, I have had the opportunity to listen to recordings from the hydrophones deployed last year which we recovered during the trip. So far, they have some interesting stories to tell. For example, two days before we arrived at one hydrophone, it recorded a pod of orcas in the area which we never saw from the bridge. In this way, the acoustic data from the hydrophones helps us fill gaps in our marine mammal observations and inform our knowledge of marine mammal presence in the area.
The next natural question to ask is why do we care about marine mammals in the northern Bering and Chukchi Seas? For starters, marine mammals provide an important food source for indigenous communities in the region. Hunting marine mammals has allowed humans to subsist in the harsh Arctic environment for millennia, and the subsistence hunt is an important component of Alaska Native culture. Understanding the health of marine mammal populations in the northern Bering and Chukchi Seas is a food security issue as much as it is an ecological concern.
Secondly, as the top predators in the region, marine mammals are important indicators of the health of the ecosystem. It takes a lot of food to feed a ~36-ton gray whale, and if there are many gray whales (sometimes we count them in the hundreds) in an area, that area must have a high enough density of food to support a large population.
Conversely, if we do not observe marine mammals in an area that historically had large numbers of animals, that could indicate an environmental shift. Such information is vital for tracking the impact of climate change, human activity, and other impacts.
Finally, we are interested in observing the marine mammals of the northern Bering and Chukchi Seas for the sake of scientific curiosity and discovery. There is still much to learn about the behavior of marine mammals. Basic questions about their lives and whereabouts remain unanswered. For example, how do they find food in the vast ocean? What brings them to the Arctic in some years and not others? How do they navigate to the same feeding locations every summer?
A longstanding scientific question of mine is if Northern fur seals spend most of their time swimming in the open ocean, how do they rest?
During this trip I found a potential answer when I observed a Northern fur seal resting in a floating ‘bed’ of bullwhip kelp that was ripped out during a storm and had become tangled together. Observations like this are what makes working as a MMO on a research expedition exciting and give us information on marine mammal behavior that would not otherwise be obtainable. Such discoveries also make the hours spent staring at waves all the more worth it.