Overfishing Krill (Secondary) - Lesson Three
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Lesson duration is: 45 minIntroduction
This lesson discusses the methods of catching krill.
Instructions
Time: 45 minutes
Contact: education@seashepherdglobal.org
© Sea Shepherd 2025
Instructions
Items in this lesson
Slide 1 - Slide
This lesson is provided by Sea Shepherd. Sea Shepherd was founded in 1977 and is a marine conservation organisation working to protect the oceans and marine wildlife. Sea Shepherd works globally on a range of issues impacting the oceans, running numerous direct action campaigns each year.
Slide 2 - Slide
During the lesson we will use these icons to identify the learning actions.
Slide 3 - Slide
Today we are going to take a look at krill fishing. Krill are mainly fished in Antarctic waters and around Japan. We will focus on Antarctica.
Fishing activities in Antarctica, including for krill, are regulated by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) which was established in 1982. Although they set “precautionary catch limits” in the 1990s to prevent overfishing of krill, many scientists consider these quotas to be outdated (the last survey was in 2006), and inadequately consider the effects of climate change and the technological advances of the krill fishing fleet.
Fishing activities in Antarctica, including for krill, are regulated by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) which was established in 1982. Although they set “precautionary catch limits” in the 1990s to prevent overfishing of krill, many scientists consider these quotas to be outdated (the last survey was in 2006), and inadequately consider the effects of climate change and the technological advances of the krill fishing fleet.
Slide 4 - Slide
A single krill supertrawler can bring in a catch of 500 metric tonnes per day.
500 metric tonnes is equivalent to what 150 humpback whales would eat per day.
These trawlers are around 120 metre in length, equal to the length of 8 humpback whales, and can hold up to 4,000 tonnes of krill.
Because of climate change, changes in sea ice and rising temperatures mean vessels can stay longer and fish in areas that used to be covered in ice. A recent investigation into the global fishing industry by the Environmental Reporting Collective found that catch limits for Antarctic krill were reached in just 69 days, as opposed to an average of 130 days over the previous five years.
500 metric tonnes is equivalent to what 150 humpback whales would eat per day.
These trawlers are around 120 metre in length, equal to the length of 8 humpback whales, and can hold up to 4,000 tonnes of krill.
Because of climate change, changes in sea ice and rising temperatures mean vessels can stay longer and fish in areas that used to be covered in ice. A recent investigation into the global fishing industry by the Environmental Reporting Collective found that catch limits for Antarctic krill were reached in just 69 days, as opposed to an average of 130 days over the previous five years.
Slide 5 - Video
This video of krill supertrawlers (2.02 min) was taken during Operation Antarctic Defense and shows the enourmous size of the vessels and nets.
https://www.youtube.com/watch?v=e7inUvTBy34
https://www.youtube.com/watch?v=e7inUvTBy34
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There are no laws preventing industrial super-trawlers from seeking out pods of whales feeding on dense patches of krill, then dragging their massive nets right through the middle of them to scoop up the krill by the ton (similar to how tuna fishing vessels used to target dolphins).
In addition to stealing food from the mouths of whales, what else could be the implications of this action?
In addition to stealing food from the mouths of whales, what else could be the implications of this action?
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One of the risks for whales is being hit by these vessels, which could cause severe injury or even death.
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There is also a risk that marine life or birds could become entangled in the nets. The nets are large enough to trap and drown whales. The catch of species like this is referred to as by-catch.
Evidence of whale deaths has been documented. In January 2023 a humpback whale died in the net of a Norwegian krill-fishing vessel, and three juveniles were killed by the same company in 2021.
Evidence of whale deaths has been documented. In January 2023 a humpback whale died in the net of a Norwegian krill-fishing vessel, and three juveniles were killed by the same company in 2021.
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The presence of industrial trawlers also creates pollution in this once-pristine environment through emissions, oil spills and the loss or dumping of deadly fishing gear.
There is also the introduction of invasive species through biofouling. Biofouling is an accumulation of microorganisms, plants, algae and animals on the submerged hull of ships.
There is also the introduction of invasive species through biofouling. Biofouling is an accumulation of microorganisms, plants, algae and animals on the submerged hull of ships.
Slide 10 - Video
This video (1.07min) taken during Sea Shepherd’s Operation Antarctic Defense, gives students another look at the size of the vessels compared to marine species.
https://www.youtube.com/watch?v=xTQcsXvulzY
https://www.youtube.com/watch?v=xTQcsXvulzY
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Close
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Refer Lesson Guide for activity suggestions.
