Aboard the RV Sanna, our days rotate around meals, fishing, and experiments.
Our ship is the newest vessel of the Greenland Institute of Natural Resources. Her name, RV Sanna, inspired from ‘Mother of the Ocean’ in Inuit mythology, shows the Institute’s commitment to safeguarding the aquatic environment and to advising governments on the sustainable use of living oceanic resources.
At 32 metres long, Sanna is small for an ocean-going vessel. She is, however, well-designed for scientific research in the marine environment. She is five stories tall, with engines in the bottom and the bridge, where the Captain sits, at the top. Our rooms are above the engines and below the waves.
As the only female scientist aboard, I knew I’d have to share a room with one of the men. I ask for he-who-is-least-likely-to-snore, and that turns out to be Emil. He takes the bottom bunk, I take the top. It isn’t easy climbing up there on the rough seas. When a five-story-tall boat hits rough seas, you can really feel it!
Rocky ride to the fjords
From Nuuk, the 40-hour transit south to the fjords near Narsaq is really tough. We head down along Greenland’s west coast towards Cape Farewell in gale force winds. The northerly winds hit the ship at around more than 12 metres per second as we get to the open sea and worsen overnight, creating five metre swells waves hitting our ship from all sides. Most of us need to use the patch against seasickness. One of its side effects is blurred vision, so I spend the first few nights half blind trying not to roll out of my bunk.
Life on board tries to proceed as normal during the onslaught. Our cook Caroline makes a valiant effort to feed us despite the sensation of living inside of a washing machine. At lunch one day, Caroline is caught off-guard by a rogue wave. It hits the ship so hard that she and everything else that is not tied down goes flying five metres through the air and across the room. Chairs break, and dishes in the kitchen fly out of the cupboards and smash!
Living conditions improve when we finally reach the calm waters of the southern fjords, and pull into the port at Narsaq. In the quiet of the harbour, we set up our scientific equipment. Microscopes come out of boxes, chilling water circulators are plugged in, and apparatus used to measure all sorts of forces (like pressure, flow and tension) are calibrated. Most importantly, everything is placed on top of non-slip mats and is tied down, just to be safe. In the evening, we head into town to have a pint, meet the locals, and ask them where the sharks are. The Greenland shark is very common bycatch for the major Greenlandic fisheries (like halibut), so the local fishermen know which fjords harbor sharks of which sizes. We celebrate everyone surviving the 40-hour transit in the rough seas, and buy some more dishes for the galley!
The pub is in a wooden shed, serves local microbrews, and features a band playing Greenlandic folk songs. I get asked to dance by an elderly Greenlander. I don’t think I have the right moves; we don’t even last a whole song!
We get back to the ship around midnight to find it locked up. The captain must have gone off to bed. We try every door at no avail. Julius valiantly squeezes through the window used to tie the ship off, and lets us in from the cold. We all troop off to bed right away, as we need to be fresh for pulling up the longlines bright and early in the morning.
How to catch sharks, and only sharks
Long line fishing. Image courtesy of the FRDC
Longlining is a fishing technique we use because the sharks swim up to 1.5 kilometers deep. The longline is the main line of reel that starts and ends with a buoy that floats on the top. Between the buoys, our longlines sit at around 200 metres deep. From that main line, are a series of lines that end with baited hooks. These secondary lines are between 100 and 200 metres long. You can vary the depth of each set of lines to place the hooks in the part of the water column where you expect your fish to be. We usually set one or two longlines each morning and evening.
Each of our sets of lines has about ten hooks baited with ringed seal that we buy from local hunters. Seal meat is a common food in Greenland, but apparently sexually mature males don’t taste very good, so this is what we buy to bait the hooks. Seal meat is very oily and attracts the sharks better than other fish-based bait. Stomach content analysis confirms that these sharks eat seal. In fact, their stomachs contain whole seals suggesting that they sneak up from the depths and swallow the sleeping seals whole!
Longline fishing has been criticized, especially in commercial fisheries such as for swordfish, because of the large amount of bycatch: the other marine creatures that are caught unintentionally. It’s a major problem for fisheries and is something that governments, environmental groups, and commercial fisheries are working to reduce globally. Our crew knew the correct combination of bait, depth and positioning needed to prevent bycatch. In our ten days of setting longlines, we caught 27 Greenland sharks, and had no bycatch whatsoever.
Follow #SharkDiary on Twitter to see all the updates about the expedition.
This expedition was made possible by funding from the Danish Centre for Marine Research, the Greenland Institute of Natural Resources, The Danish Natural Science Research Council and the Carlsberg Foundation.