Challenging Habitat Blog

Back on Dartmoor!

The expanse of valleys and tors, a distant glimmer of the sea.

What a treat!

An ancient stand of oak amidst boulders, moss and lichen.

The call of a cockoo.

Swathes, no, ‘fields’ of cotton grass like I’ve never seen before.

A sheep-free zone and freedom for my dog.

Crossing a water course, getting soaked knee-deep.

A good workout climbing out of the valley.

Buffeted by a sharp wind on top of tors. Time to put on a woolly hat!


Evocative names on the map: Devil’s Tor, Foxholes, Tinner’s Hut, Beardown Tor, Crow Tor…

Torrents cascading over large rocks in a beechwood valley.

Uplifting. Restorative. Magic.

The first dull day in weeks, sadly bringing little rain.

Still, the coast always offers new perspectives. This succulent plant is adapted to harsh conditions on top of a rock within the reach of sea spray: salt, sun, dessication, little soil, storms.

Resilient in its challenging habitat.

The sea.

It’s good to come back to the coast, see the sea, hear it, smell it and feel it.

A refreshing swim, enjoying the gentle swell.

Revitalised! Calm and content.

Red, or Antarctic krill oil is marketed aggressively. It’s hailed as the new super-supplement for your heart and brain and vision. It has made its appearance on the shelves of whole-food shops, online health and fitness stores and your chemist down the road. True, krill contains high concentrations of vitamins A and E, and 70% of krill lipids are undersaturated fatty acids. However, the nutritive value of krill protein (~12-15% of krill’s weight) is actually lower than whole-egg protein (Suzuki & Shibata, 2009)

Obviously, there is a massive industry harvesting marine resources – fishing is nothing new and ubiquitous in all oceans. I’m no expert on Antarctic ecosystems, but have read enough to know that the Southern Ocean is a fragile ecosystem under pressure due to by climate change. Some scientists predict that a warming ocean will diminish the krill population (Hill et al. 2012) and that makes me think that any competition krill predators receive is not good news.

Let’s explore some facts. Krill being a keystone species in the food web (see illustration), any large-scale reduction in its biomass may force krill predators to shift to other food sources (e.g. copepods, a form of zoo plankton), or face a reduction in numbers. Either scenario has the potential to alter the food web, species composition, biodiversity and ecosystem as a whole.

food web in Antarctic waters

Simplified Antarctic food web, showing the direct dependence of fish, penguins, squid, sea birds, seals and baleen whales on krill biomass as food source. Adapted from

As early as 1982, Beddington and May raised concerns about the effects of the depletion of the food source of (then) over-exploited baleen whales due to industrial krill harvest in the Southern Ocean. Some baleen whales are making a come-back thanks to their protection by international treaties (e.g. International Whaling Commission) and being major consumers of Antarctic krill, are in direct competition with the krill industry.

Today, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) regulates the commercial fishery for Antarctic krill (Trathan 2018). It aims to follow the principles of conservation to prevent the unsustainable depletion of any ‘harvested’ population to levels that cause changes in the marine ecosystem that are not reversible in the time-frame of several decades. Trathan (2018) reports that krill stocks were estimated at approximately 60 million tonnes in 2010 and the CCAMLR catch limit for krill at 5.61 million tonnes was based on this estimate, with further detailed restrictions on specific geographic locations. Nevertheless, there are concerns about the monitoring methodologies and the timing of krill fishing, which, some argue, should be seasonally restricted with considerations to temporal and spacial aspects of breeding and feeding patterns within the ecosystem.

Antarctic krill is not only used as human food supplement, but also for animal feedstuffs, particularly in aquaculture. Aquaculture is one of the fastest growing areas of food production in China, where more than half the country’s overall seafood production is farmed. I wonder whether expanding markets for farmed seafood and ‘super-supplements’ will result in pressure on the CCAMLR to increase the catch limit for krill in the future? How are the power relationships between industry and this organisation? While it appears that currently, krill harvest in Antarctic waters is sustainable (Trathan 2018), how will the ecosystem respond to rising sea temperatures and in turn, how will the CCAMLR respond to that, and is it capable to do this in good time?

For the consumer, this is really about critical thinking, ecological economics and sustainable living, and asking some fundamental questions:

  • For what purpose is Red Krill Oil (you can insert all sorts of other products here) manufactured?
  • What tempts me to purche Red Krill Oil? Is it to fulfil a real need for my body for the nutrition it contains? Is it to strive for a body image that has become desirable to my thinking because of clever marketing by companies supported by ‘fitness gurus’? In other words: does it fulfil my own needs or those suggested by others?
  • Can I obtain adequate high quality nutrition from less controversial, more sustainable sources?

The way I see it, exploitation of fragile and reasonably pristine environments can only begin to be justified if it is absolutely necessary to satisfy basic nutritional needs that cannot be otherwise met. Clearly, the marketing craze for Red Krill Oil is targeting wealthy people in affluent societies that can easily satisfy their nutritional needs in a myriad of other ways. Of course, questioning the sustainability of anything we do and consume is one of the most important first step on the road to more sustainable living.

Featured Image

Antarctic Krill. Antarktický krill” by Norkrill is licensed under CC BY-NC-ND 2.0  Creative Commons.


Beddington JR, May RM. 1982. The harvesting of interacting species in a natural ecosystem. Scientific American 247 (5) 62-69.

discoveringantarctica. 2020. Ecosystems and foodwebs.

Hill SL et al. 2012. A foodweb model to explore uncertainties in the South Georgia shelf pelagic ecosystem. Deep Sea Research Part II: Topical Studies in Oceanography.

Suzuki T, Shibata N. 2009. The utilization of Antarctic krill for human food. Food Reviews International

Trathan P. 2018. Managing the fishery for Antarctic krill: A brief review of important environmental and management considerations. Scientific Report, British Antarctic Survey.

In August 2019, environmental and ocean scientists from various universities, including myself and Richard Sandford from the University of Plymouth, loaded a lot of scientific equipment on board the tall ship Pelican of London for a week of sail training and science education. I wrote about this in a previous post called ‘You take care of what you love, don’t you?

Now we are preparing for more: the ocean science programme “Sea the Future” is coming to Plymouth in the Mayflower 400 year of 2020, for 4 x 10 days of sail training and environmental marine science in April/May and September.

Check out what’s on offer at Sea the Future website and watch the ocean science video, and check out more about marine careers and training on the website or get to the facebook page or instagram.

I hope to see you aboard sometime!

%d bloggers like this: