Where do the auks go to find food for their chicks? What prey are available to them? What are the characteristics of the water masses that they foraging in?
In order to answer these questions we went aboard the R/V Oceania for two days for a round the clock oceanographic survey of the water outside of Hornsund Fjord.
The Oceania is a three masted oceangraphic ship that sails from Poland to the Arctic every summer for oceanographic work.
While travelling along transect lines, we recorded all the birds within 300 meters off of one side of the ship. We noted the number of birds in each flock, the species of birds, and the behavior of the birds. One person would call out their observations while another used the computer to record them. We used a special program on the computer that made it easy to enter all of these data in a few keystrokes. For example, “5 little auks flying southwest, 1 northern fulmar flying towards the ship, 2 black-legged kittiwakes sitting on the water” can all be in the computer by hitting only 10 keys.
Here is Derek recording the observations made by Laurel.
The ship stopped along the transects at stations where oceanographic measurements were made by the zooplankton biologists and physical oceanographers aboard. First the physicists would lower an instrument called a CTD (Conductivitiy Temperature Depth sensor) into the water. The CTD measures the temperature and the salinity of the water as it descends. These data allow us to know if the water being sampled has Arctic or Atlantic origins. Next the zooplankton biologists pull a net through the upper 50 meters of the water. This net catches the zooplankton that little auks could eat.
Roman and Rafal pull up the multinet. This net is specially designed to sample different layers of the water column with multiple nets that open and close at different depths. We used this net twice during our surveys and at the rest of the stations we used a simpler hoop net.
We crossed the shelf break several times and each time we saw loads of Atlantic white-sided dolphins and whales. It was easy to know when the dolphins were around because they were always attended by flocks of black-legged kittiwakes. These birds would periodically swoop down to the water in unison to catch fish that would rise to the surface trying to evade the dolphins. When we first started our surveys, the seas were relatively calm.
Our view during the first part of our at-sea surveys.
Later, the swells increased and we were tossed around a bit. Dishes fell off the tables and we would slide across the benches where we sat to eat. Derek finally realized why the steward only filled the glasses with juice halfway.
Waves crashing over the bow of the Oceania during the later part of the survey.
When we weren’t counting birds, we were horizontal in the lounge.
All is all it was an excellent trip. We counted 990 little auks in 2 days!
We wish the captain, crew and scientists gentle seas for the rest of their surveys!