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Half way through the AKES research cruise

Time flies even faster here in the Antarctic Ocean than it does at home. The weather has been great. But even in the middle of summer the temperature here is only 3 degrees centigrade. Comparatively, the summer in Bergen last year was fabulous. 

Above: Rolf Korneliussen and Svein Iversen with some of the krill catch.

The research cruise so far has been a fantastic experience with ice bergs, penguins, seals, whales and albatrosses. On South Georgia we even met birds that might have visited Bergen on their migration from one pole to the other. Grytviken, however, has been covered so thoroughly in this cruise diary that I will only say that it will be a memory for life.

Eventually, we finished calibration of the acoustic equipment just outside Stroemness, an old Norwegian whaling station not far from Grytviken. Calibrating is like a balancing act when it comes to keeping the sphere within the echo sounders beam. A complicated system of fishing spools and rod-like gear was used to achieve this. This time calibration was done in unknown waters, without moorings, and with plenty of curious and playful seals and penguins around. Luckily, they showed limited interest in the spheres used for calibration.

Immediately after leaving the South Georgia shelf we caught two tons krill and a few ice fish juveniles. We immediately dug out the reference books and have over time almost become experts on phytoplankton, zooplankton and various fish species. The ice fishes are especially interesting with their transparent blood due to the lack of red blood cells. That our retired colleague Steinar Olsen is referred to in several papers on this topic is really nice. He worked with Antarctic cod an ice fish on South Georgia early in the 1950s.

Ice fishes caught with the trawl close to South Georgia.

When the rest of us have to study both the objects and the literature closely to identify the species, the oceanographers have it easy. Measuring salinity and temperature is the same all over the world. The abundance of krill is such that we have difficulties limiting the catch. Our first trawling for fish with the Åkra trawl failed because caught large quantities of krill on its way down. Krill is not the only plentiful species in this area. The same goes for amphipods, which are small shrimp-like crustaceans one to two centimeters long.

We have deployed both landers twice, which are acoustic measuring devices that use echo sounders to observe the activity of krill, plankton and fish as well as seals and penguins. In addition we obtain valuable information about the echo strength of krill and ice fish from these stations which is one of the main objectives with this research cruise. We are happy that we have collected so much valuable data that eventually will reveal what are the correct echo signals from krill and ice fish, depending on their angel and orientation.

The end of the trawl is pulled in the trawl gate.

This is substantial and complicated work but we aim to have results ready for when CCAMLR’s work group for krill gathers in St. Petersburg next summer. Unfortunately, so far the BBC photographers have not been able to film schools of krill at surface levels. They are optimistic, however, and hope to get a chance to film this around the Bouvet Island. The geologists, on the other hand, are pleased with the data they have collected from the core samplers.

Time and favorable weather conditions have even allowed them some bonus sampling. We still have two of them on board whereas the other three left the ship at Grytviken to continue core sampling on South Georgia. We also collect data for NASA when the sun is shining. The space organization is interesting in aerosol data from the sun and we all hope for many sunny days.

An amphipod, a small crusteans just a few centimeters long crustaceans.

Just before leaving South Georgia a trawling resulted in 350 kilo fish, predominantly mackerel ice fish. We arranged a fish breakfast early this morning and all attending agreed that nothing beats a self-fished meal. It was agreed that painted rockcod was the tastiest of the species we sampled.

A cruise ship passing in front of a huge iceberg.

Right now we are sailing toward the Bouvet Island with a small storm coming from behind. The research vessel “G.O Sars” behaves exemplarily in the water. We will arrive at our first research station tomorrow evening. Around the Bouvet Island we will sample the pelagic ecosystem. On the island there are five observers from the Norwegian Polar Institute who has been there since mid December. They have tagged fur seals and have observed their feeding habits. It will be interesting to compare our observations of krill, plankton and fish with how and where the permanent inhabitants of the Bouvet Island obtain their food.

Svein Iversen
cruise leader