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The hunt for krill continues around the Bouvet island

The Bouvet Island is the southernmost island on the Mid-Atlantic Ridge. It is situated in the middle of the Southern Ocean between Cape the Good Hope in South Africa and the Antarctic continent, at 54° 25’S and 3° 21’E. This small and uninhabited volcanic island measures 7 x 10 km, reaches 780m above sea level and 94 % of the surface is covered by a glacier.

Above:
The Bouvet Island visible from the Southern Ocean on board G.O.Sars, with the large glacier covering 94% of the entire land area. Photo: Leif Nøttestad

The island was discovered in 1739 by the French marine officer Jean Babtist Charles de Lozier Bouvet. With two ships equipped for an 18 month survey, his ambition ambition was to find a legendary terrestrial area in the south, the Terra Australis. This land was supposed to be lush and inhabited by friendly humans. The disappointment was big when they after a strenuous journey at last got land in sight. What they named the Cap de la Circoncision, today known as the Bouvet Island, they found to be nothing but gravel, rocks and ice. They made a hasty return, without even making a landing ashore, taking precise positions, or explore the coastline. They believed this place to be part of a larger continent and not an island.

The first landing on the island occurred approximately 100 years later and the island has been visited by a number of expeditions during recent age. In 1927 the island was annexed by Norway during a Norvegia expedition and has later been enrolled under Norwegian sovereignty and received the status as nature reserve. As a curiosity; Norway are also in possession of the northernmost island on the same seamount, however on the other side of the globe; the Jan Mayen Island.


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Chinstrap penguin hunting for krill east of the Bouvet Island. Photo: Eirik Grønningsæter

The Bouvet Island is the only land area in a vast ocean. The island is crucial for several animal species. Seals, penguins and other seabirds must all be on solid ground for successful reproduction as well as periods of fur and feather molting. The shelf area around the island with variable depth (e.g. sea mount’s) creates mixing and changes of currents of water masses. This provides favorable growth conditions for the primary producers (phytoplankton) on which animals, like the krill, depend. The Antarctic krill (Euphasia superba) constitutes the world’s largest single species biomass and is a key species in the Antarctic ecosystem. The combination of land fast area and favorable nutritional conditions makes the sea areas around Bouvetøya a fruitful oasis within an acceptable radius for the land-base dependant animals.

Because of its high biomass, rich proteins content, pigments (carotenes), natural antioxidants and omega-3 fatty acids, the krill is an important species for future commercial exploitation on a large scale. Since the knowledge about this species at present is minimal, it is of high importance to collect scientific data for management purposes. With this aim an international management program is initiated, CCAMLR (Convention of the Conservation of Antarctic Marine Living Resources), with the purpose to coordinate research and to give advice for harvesting techniques and to set quotas for harvesting levels of commercial krill fisheries in the Southern Ocean.


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Even here in the worlds most weather hostile regions is it possible to chill out amongst the aboriginals. Photo: Greg Hofmeyr

Today the Norwegian Polar Institute is responsible for Norway’s contribution in CCAMLR when it comes to population studies of top predators on the Bouvet Island, mainly seals and penguins. Such studies provide indirect indications of the krill population status in these ocean areas.

However, the adjacent waters to the Bouvet Island has received very little attention from research investigations and during this particular cruise the Norwegian Marine Institute and this AKES Expedition has the objective of making direct measurements of the status of krill along pre determined stations.

We are using advanced acoustic methods and a range of different instruments for measurements of hydrography. This is to obtain the best holistic picture of the biomass, biology and to map interspesiphic biology and physical factors that influence on the krill viability.

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Bjørn Krafft at the Bouvet Island during a previous expedition. In the front a Southern elephant appears; maale mass of this species can reach max 3600 kg and the population size in this area constitutes of a couple thousands individuals. Antarctic fur seals are seen in the background, their body mass is approximately 180 kg at maximum, and the population at the Bouvet Island is around 75 000 animals. Photo: Greg Hofmeyr

For those that have been visiting this homepage and followed the cruise reports regularly know that this expedition also has made scientific studies of krill longer north and further south than the latitudes of Bouvetøya. It is interesting to note that our preliminary results show that the krill in the Bouvetøya waters are both larger and are in a better condition compared to other locations we have investigated. This also seems to imply for other animal groups that are included in this research program. Despite that this area is situated in one of world’s most hash areas weather-wise, a number of creatures seem to grow, reproduce and enjoy life in these regions.

 Happy Easter!

  

 

Written by


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Bjørn A. Krafft, PhD, IMR


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Leif Nøttestad, PhD, IMR