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Don’t Krill My Vibe: How Human Demand For Krill Is Threatening Antarctic  Ecosystems

Image adapted from original by Uwe KilsRecent demand for krill based products has alerted the attention of environmental organisations such as Greenpeace who are determined to curb the trend. Krill are crucial players in the Antarctic food chain; feeding primarily on algae they support a vast web of life from Adélie penguins to blue whales. Among Greenpeace other notable naturalists have joined the campaign; Chris Packham’s article for the Guardian summarises the fishing for krill as an ‘eco-disaster’.

Fishing operations have been occurring in ‘pristine’ Antarctic waters since the beginning of the 21st Century. Krill products have become a prized and sought after commodity. In the past the industry’s ‘sustainable’ practices have been able to slip under the radar. However a recent report published by Greenpeace provides substantial evidence that suggests a very different reality.

Tracking data revealed that vessels had anchored specifically in marine protected areas despite the potential impact on both wildlife and the geology. The team also observed ‘risky fishing practices’ consisting of the transfer of catches to ships with a history of infringements, poor safety records and low standards in pollution prevention in relation to oil and sewage. This type of fishing - ‘transhipping’ - is often associated with human exploitation and the breaching of human rights. In addition the potential environmental impact of oil spills, fires and groundings would disrupt the balance of trophic structures and alter the chemistry of Antarctic waters.    

Flickr | Health GaugeKrill products have flooded the market in recent years in the form of omega 3 supplements and as a main ingredient in commercial fish foods (ironic right). The sheer variety of krill based products has increased demand which has accelerated harvesting in the Southern Ocean. The demand coincides with the advancement of new maritime technologies, allowing fisheries to locate larger catches more efficiently, and therefore increasing their overall yield.

Fisheries are harvesting inside the historical feeding grounds of whales and other marine species, increasing the overall competition for food. Vessels with a dominating presence in these areas may force species to travel further to find adequate feeding grounds. For nesting penguins this poses a major problem as they cannot travel too far to forage when raising their young. Evidence collected by Helena Herr of the University of Veterinary Medicine Hannover in Germany states that fin and humpback whales of West Antarctica forage in different areas. This limits interspecific competition for krill however populations foraging in the same area would potentially still face competition from krill fisheries.

So why are krill so important?

Without an adequate supply of krill, many species of whale such as humpback and fin whales would lose a key source of food. But this is not the only reason why we should protect krill – these small crustaceans are vital in supporting oceanic health due to their relationship to other marine organisms.
Oceans act as carbon sinks; phytoplankton in the water sequesters over 2 billion tonnes of carbon dioxide annually, and the polar waters of Antarctica hold one of the largest ranges for phytoplankton. These microorganisms also act as the foundation for many oceanic food chains.

Flickr | Siyavula EducationIron is a micronutrient required for phytoplankton growth and photosynthesis, and its availability in the water is governed by physical, chemical and biological processes. Scientists have recently studied the symbiotic relationship between whales and krill, and believe whales to be responsible for a crucial stage in biogeochemical cycling - the consumption of nutrient rich krill and subsequent defecation.  

This relationship between krill biomass and whale faeces is a relatively new discovery, but evidence would suggest that after eating krill, whales’ defecation releases iron into the water, which supports the growth of phytoplankton.  In order to conserve the Southern Ocean ecosystem, conserving krill stocks is therefore imperative.

Plans to increase the commercial industry of krill and the climate change related effects on krill biomass are unpredictable. Herr states ‘’direct surveys that target both krill and their predators, such as baleen whales need to be undertaken concurrently .This is to monitor and ensure that habitats in the Southern Ocean will continue to support a humpback whale population that has just touched pre-exploitation numbers.”

By Matt Couldwell - Online Media Intern

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