Talk notes: Why whales are marine ecosystem engineers

Dr Jocelyn Elson-Riggins gave us a fascinating insight into the research being done on the impact of whale populations on marine ecosystems. The Rugvin Foundation in the Netherlands was established to monitor whale populations and Jocelyn first worked for them as mentor for a scientist carrying out their PhD research on lungworm parasites in whales. In studying whale poo, they gained valuable understanding of the importance of its role in the ecosystem of our oceans.

In the mid twentieth century, when we lost half the population of whales in the Southern Ocean due to intensive whaling, the counter effect of an increase in krill, key food source for baleen whales, was expected, but these small shrimp-like crustaceans actually decreased in quantity during this period. Why was that?

To give an example of the number of krill consumed by a whale, we learned that a Blue whale, the largest animal ever to have lived on our planet, eats 40 million krill and releases 5000 kg of poo a day, the weight of an elephant. Whales come to the surface to poo, due to the water pressure, and surprisingly for its weight, it floats (and is very stinky)! We inspected slides of yellow masses of floating poo and were introduced to an important member of the research team, Fargo the Rottweiler, who despite suffering from motion sickness could scent whale poo in the water up to a nautical mile away, which vastly sped up their collection rate.

Whale poo has nitrogen, phosphorus and iron and whale urine has nitrogen and phosphorus, all necessary in the fertilisation of phytoplankton on the surface of the ocean. As whales feed at the poles, lots of poo is deposited there and as they migrate towards the Tropics their urine nourishes the oceans. Phytoplankton, the food source for krill, consume carbon dioxide from the atmosphere and release oxygen and glucose, thus playing a vital role in our planet’s carbon cycle and oxygen production. Once you deplete the whale poo stores of the marine ecosystem, the phytoplankton, krill and the photosynthesis cycle are affected, leading to a decrease in krill.

Jocelyn also talked about the whales’ role in carbon storage, how a Bowhead whale for instance can live up to 200 years in the Arctic, holding the equivalent carbon of 1500 trees. When it dies a natural death and falls to the sea floor it gives a lot of food to deep water organisms, with its remains locked into the sediment.

Jocelyn finished with some examples of why we need to continue campaigning for the protection of whales.

• Krill fishing is on the increase for the supplements, pet food and  fish food industries.
• The Convention for the Conservation of Antarctic Marine Living Resources in 2024 failed to create new Protected Areas since Russia and China refused to agree any changes.
• Whaling continues in Iceland, Norway, Japan and the Faroes.
• 300,000 whales are estimated to be caught in nets as a result of bycatch globally each year
• Plastics in the oceans mean that pollutants build up in the blubber and toxins pass to their calves who then die.
• The likelihood  of ship strike has grown with the increase in shipping around the world.

This was a very interesting talk which sparked many questions and much discussion afterwards. A donation will be given to the Rugvin Foundation by the Society in lieu of a speaker's fee at Jocelyn's request.