A herring bonanza
There was great astonishment along the coast of Tromsø in 2011 when large numbers of humpback whales and killer whales suddenly arrived in the fjords. What was attracting whales in along the coast, and what was really going on under the water? www.nordnorge.com contacted Martin Biuw, senior researcher at Akvaplan-Niva in Tromsø and Professor Audun Rikardens at The Arctic University of Norway.
A natural phenomenon
Norwegian spring-spawning herrings fatten up in the Barents and Norwegian Seas during the summer. Towards autumn they travel south to the area outside Tromsø, Senja and Vesterålen. Audun Rikardsen says that the herrings remain in shoals and save their energy while waiting to spawn. At some point in February, they travel further south to spawn in the sea there. These large herring shoals are followed by predators and fishing boats.
Lunch on the go
Before and after Christmas, the humpback whales make their way down from the plentiful waters of the Barents and Norwegian Seas to Caribbean or West African waters. This species of whale is one of the animals with the longest migration routes in the world, and mating and birthing take place during migration. Huge amounts of herrings appear along the way giving the humpbacks a chance to stock up. “A sort of pit stop” Rikardsen says.
Martin Biuw explains how the humpback whale hunts. If the herrings are grouped closely together, the humpback whale descends to 60-70 meters (approximately 200-230 feet) or even deeper and helps himself. If the herrings are in shallower water or more spread out, the humpback whale lunges down quickly and then surfaces with its mouth wide open. The whale takes in hundreds of herrings at once and filters out the seawater using its baleen. For a brief moment, the humpback whale is in free-fall in the air.
Killer whales are known as the wolves of the sea. They hunt in groups; they encircle the shoal, enter it one after the other and tuck in to lunch. Often the killer whale will strike its tail in the water stunning the fish. When herrings began coming to this area some years ago, there were very few killer whales. Now, however, you can see several hundred all at once. The herrings’ reputation throughout the marine world has obviously spread.
This reputation is spreading underwater
Killer whales communicate via a well-developed set of sounds. According to Martin Biuw, it appears that humpback whales recognise killer whales’ herring signal. Humpback whales can suddenly appear and feast on the herrings that the killer whales have gathered up. Both humpback whales and killer whales have learned how to recognise the sound of the heavy machinery hauling up seine nets into seiners, and after a few minutes the whales swim around the boats. The fishermen also look out for the whales, because then they know that the herrings are close by.
The herrings are leaving
This natural phenomenon is on borrowed time. Maybe this year, next year or in five-ten years, the herrings will be gone; at the least their numbers will be greatly reduced. The reasons why they will no longer be here are not fully clear, but the younger generations are changing their behaviour. Almost like a youth rebellion, the younger generations are simply going to other places. In the 1990s, herrings could be found in the fjord of Tysfjorden in Nordland county, but from 2011 onwards, they could be found along the coast from Tromsø to Vesterålen. We don’t know where they’ll go next, but it could well be far out to sea.
Join us and register
Whales have big personalities. If you come on one of the many whale safaris that go from Tromsø, Senja or Andenes and get a really good photo of a whale fin, you could be helping our researchers. Whale fins are a clear, unique identification mark on the whale, rather like a fingerprint.
- For humpback whales, please upload your photos to www.hvalid.no
- For killer whales, please send your photos to researcher Eve Jourdain of Norwegian Orca Survey at email@example.com
- If you would like to join us on a whale safari in Tromsø, we have quite a range to choose from:
- Check out the following from Senja:
- Two companies in Andenes:
Where can you book a whale safari?
If you would like to come on a whale safari, please see below
- There are many tours from Tromsø and Sommarøy. Please check the Visit Tromsø homepage.
- Trips from Senja depart from Hamn in Senja and Mefjord Brygge
- In Andenes you can travel with Whale Safari or Sea Safari Andenes
NB! IT SEEMS LIKE (NOVEMBER 2017) THAT THE WHALES HAVE MOVED NORTH TO SKJERVØY/KVÆNANGEN/ALTA. NOW TWO TRIPS ARE ON OFFER IN ALTA: