Save the krill, save the world

It may seem counterintuitive, but to protect some of the largest animals on earth we must preserve some of the smallest. A vital consideration in protecting whales – and perhaps life as we know it – is protecting their food sources.

The whale pump

The baleen whales (like humpbacks, blue, and right whales) depend on krill – tiny shrimp-like crustaceans – as a food source. These are found in especially huge numbers in the summer feeding grounds of southern cetaceans around the coasts of Antarctica (and the Arctic for northern populations). Blue whales eat up to 16 tonnes of krill and other plankton every day, capturing hundreds of thousands of the tiny crustaceans in a single mouthful.

This diet is important not just for the whales’ health, but for the health of our oceans. Whale faeces, it turns out, is a huge contributor to essential nutrient distribution throughout the ocean, and beyond. Krill are rich in iron and other nutrients, and when those nutrients come – digested – out of the other end of a whale, they are released into the water at the surface, where they support microscopic phytoplankton. Phytoplankton are krill’s main food source, so this nutrient support completes the cycle that ensures the health of the whale’s food source.

The problem? Humans also harvest krill (for things like pet food and krill oil), and if not managed sustainably, deplete stocks needed by whales and many other marine species. This is exacerbated by climate change and fluctuating ocean temperatures which can also impact both krill and phytoplankton numbers.

Ocean lungs

The support whales’ excrement gives to phytoplankton also can’t be overstated in terms of climate protection – as shown in the figure below, these organisms are responsible for producing at least 50% of the oxygen on earth – every second breath you take is thanks to these tiny ocean organisms.

Click to Expand
^{Image courtesy of Whale and Dolphin Conservation}

Deadfall carbon

Whales themselves also benefit the climate simply by existing. Throughout their lives, they sequester a huge amount of carbon from the atmosphere in their own cells. When they die, that carbon sinks to the bottom of the ocean, where it remains; now part of the deep ocean scavengers who feed on the body. As the WWF puts it:

On average, a whale throughout its lifetime captures the same amount of carbon as 1,000 trees.

The loss of whales from this system (like the at least 2.9 million whales killed during the whaling period), drastically impacts these two significant climate-regulating natural processes.

As shown in the video below, the protection of krill is a crucial initiative absolutely necessary to protect the future of both whales, and ourselves.

Further resources

Climate Change and whales, Whale and Dolphin Conservation

A strategy to protect whales can limit greenhouse gases and global warming, International Monetary Fund

With Every Breath You Take, Thank the Ocean, Smithsonian Institution