Imaginary Fish Bowls

Iceland, along with Norway and Japan, are the only countries left in the world that hunt whales for commercial purposes. A common reason given by those in favour of whaling, to justify the killing of whales in all of these countries is that whales are a considerable factor in the decrease of fish stocks – and therefore in direct competition with fisheries.

However, the marine ecosystem is far too complex to assume that by removing a certain amount of whales, the number of fish will increase. Research carried out in recent years has further upended this false claim by considering the diverse ecology of the oceans as being a fish bowl.

Whales interact with the environment in a positive manner that is beneficial for marine life and humans.

Role within the Marine Ecosystem

Trophic cascades: Stabilising food chains and ecosystems

Researchers have been working on understanding the complex interaction and role whales have within the ecosystem. One of the most obvious examples is that the decimation of many whale species has caused a trophic cascade or in other words the significant decrease in whale species and numbers has led to a disruption among other marine life, including kelp forests, sea otters, fish and marine bird life. Due to their immense size many people do not think that whales can be prey but killer whales do prey on some whales and research indicates that dwindling populations have meant that killer whales also now focus on hunting smaller marine animals such as sea otters, who in turn feed on sea urchins. With the depletion of sea otters due to increased attention from killer whales, larger numbers of sea urchins are free to feed on coastal kelp forests which in turn reduces fish stocks in addition to affecting our already fragile climate.

Whale pump: Circulating valuable nutrients

Whales also play a role as the engineers of the ocean, due to the release of their bodily fluids in what scientists call a whale pump. Whales often relieve themselves at the ocean surface when they emerge to breathe. Their excrement (as well as the nutrients within it) dissipates across the upper layers of the ocean as well as falling down the water column, eventually arriving at the sea floor. Diving whales typically feed on invertebrates and fish deeper in the ocean, so by defecating at the surface they circulate valuable nutrients that had sunk to the bottom of the ocean back towards the surface level (where many other marine animals live and feed).



Post-death ecosystem contributions

And as is the nature of life, whales also die natural deaths and when they do so their carcasses float downwards in what scientists dub “whale falls”. When this occurs numerous marine animals such as sharks and hag fish feed on sunken whale carcasses, in addition to numerous other smaller organisms in the deep sea. Entire deep-sea ecosystems are built around whale carcasses, and the nutrients they bring. Furthermore, whale carcasses are climate engineering the ocean by transposing carbon to the deep sea – essentially the carbon stored within them is brought to the bottom of the oceans when their carcasses fall.