Krill fishing in the Southern Ocean

The impacts that come with Krill Fishing in the Southern Ocean

Tiny shrimp krill are the primary food source for many marine mammals and fish.
Tiny shrimp krill are the primary food source for many marine mammals and fish.


In the 1950’s, industrial fishing was concentrated in just a few small areas of the oceans that were accessible to fishermen, but in the last 60 years fishing technology has advanced at a great rate which allows fishermen to travel further & fish for longer. The Southern Ocean is the only ocean hardly touched by fisheries, but due to technological advances fisherman can reach these new hostile environments. Large fishing trawlers & new fishing strategies in the Antarctic region are having a great impact on the food chain in this environment.

The Antarctic Krill
The Antarctic Krill; Euphausia Superba

New to the market & becoming increasingly popular is Krill oil. Krill oil – also known as the ‘Krill Miracle’ is a new better alternative to the well known Omega 3 fish oils. This Health product has had extremely good feedback off users for things such as improved concentration, as well as this it supports the function of the Brain, Heart & Eyes and is fastly becoming the ‘Diamond’ of the nutrition world. Due to it being a good quality high end product, it is also relatively pricey to buy, approximately £15-£20 to purchase 500mg ( 2013) making excellent revenue for shops selling it making it increase in demand.

Omega 3 Krill Oil
The highly profitable Omega 3 Krill Oil sold at £15-£20 for 500mg

Krill oil is also popular with fisheries, such as salmon fisheries using it to put in the pallets which the salmon feed off to give it its distinct healthy pink colouration. It is also popular on supermarket shelves in Japan & Russia. These products are predicted to have catastrophic impacts on the environment and the food chain as krill is dependent on almost entirely by every other species in Antarctica (Alonzo et al. 2003). This is what I will be talking about in my lecture.



Antarctic Krill; Euphausia superba are shrimp like crustaceans which support the entire food chain in Antarctica (M J. Kaiser et al 2011). Everything eats it; Baleen Whales, Toothed Whales, Sea birds, Squid, Albatrosses, Seals, Octopus, Fish; this is shown in figure 15.3. This ecosystem is so dependent on Krill both directly and indirectly, this makes this environment unusually fragile & could collapse at any point if tampered with. Even the largest Mammal in the world the Blue Whale relies on Krill consuming up to 4 tonnes per day. There are approximately 600 million tonnes of krill in Southern Oceans and are thought to have the largest population of any species on Earth (Sea Fish report, Fish Fight 2013). Over fishing is not the only problem facing Krill, the warming of the climate is leading to less sea ice for the Krill to spawn under, meaning Zoo-plankton and Algae cannot grow underneath these large ice sheets hosting a whole range of potential problems for the Antarctic Krill population. These Ice sheets are also broken up by huge fishing boats, therefore fishing is already adding to a big problem. Krill has declined in the Antarctic by 38-80% over the last 30 years (I Reid K et al 2010).

All the species relying on the Antarctic Krill for survival
All the species relying on the Antarctic Krill for survival
Whales fishing for Krill
Krill examined by divers in the Arctic region











New fishing technology on vessels in Antarctica have been created allowing fishermen to capture more Krill than ever before at a much higher quality, an example of this is the ‘Super Krill Trawler’ which is a Norwegian boat ran by the company Aker called the Sagasea. The Sagasea can go fishing on the Southern ocean for 30 days straight, for at least 10 months a year, fishing season is from 1 December until the 30th November of the following year. (H Østgård 2011). This vessel has a huge net beneath the boat with a hose attached to the end of it, which pumps up fresh living krill onto the ship, making the best quality krill as it is not damaged which is a new fishing tactic. It also allows this trawler to fish double the amount of Krill as there is no need to take the net out of the water. Apparently, the Sagasea fishes 120,000 tonnes of krill per year (C. Glover 2006). However when the water is extracted and the krill has dried, this ends up being about 20,000 tonnes of product ready for human consumption, oil, fish meal and pharmaceuticals. This may seem like a small fraction of the amount of Krill that is out there but because it is depended on by so many species, a lot of the Krill is already needed. No rules or regulations put in place such as no fishing zones which does not work in natures favour.


The Norwegian fishing vessel
The Norwegian fishing vessel – Saga sea.


Krill is extremely important as it is the heart of the food chain but it is also important for the atmosphere also as new studies suggest, Krill could be important for fertilizing the southern oceans with Iron, which helps to stimulate the growth of Phytoplankton which then leads on to enhance the ocean’s capacity for natural storage of carbon dioxide. Although most textbooks state Krill live mainly at the surface, they have been monitored to swim to the sea floor regularly to feed on Iron Rich fragments of decaying organisms, once they have had their fill they swim back to the surface with stomachs full of iron which later gets released into the water regulating iron around the Southern oceans. Krill are a vital part of the Southern Oceans, from food chain balance to nutrient influx, fishing to this extent may host issues for Krill and species dependent on it.






M J. Kaiser et al (2011) Marine ecology, Processes, Systems and Impacts – Polar regions (Ppges 335-7)

I Reid K, Watkins JL, Murphy EJ, Trathan PN, Fielding S, Enderlein P. (2010). Krill population dynamics at South Georgia: implications for ecosystem-based fisheries management marine ecology progress series. (pages 399:243-252)

S. Nicol, J. Foster, S. Kawaguchi. (2011) The fishery for Antarctic krill – recent developments, fish and fisheries. (pages 30-40)

V Gascón, R Werner. (2005) Antarctic Krill: a case study on the ecosystem implications of fishing (pages 7-30)

Smetacek, V. & Nicol, S. (2005). Polar ocean ecosystems in a changing world Nature (437: pages 362-368)
Frenot, Y., Chown, S.L., Whinam, J., Selkirk, P.M., Convey, P., Skotnicki, M., Bergstrom, D.M. (2005). Biological
invasions in the Antarctic: extent, impacts and implications Biological Reviews (80: pages 45-72)



9 years ago

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