This post talks about the future of sperm whales and other deep-divers in the Canary Islands. Sperm whales are such amazing animals. These whales are the world’s largest toothed whales, living up to 70 years. These giant whales are quite similar to submarine: they can deep-dive while holding their breath for about 45 minutes below 1,500 meters of depth. They spent most of their time in the deep and dark parts of our oceans looking for squids and other fish. Far from the surface, one may expect human activities would not affect them…
Sperm whales in the Canary Islands
In the Canary Islands, a Spanish archipelago located next to the northwestern African coast, we find 3000m (10 000ft) deep underwater canyons. These deep trenches in which sperm whales live and hunt are close to the shore, which makes it easier to observe and study deep-diving whales. The Canary Islands are a hotspot for other species, including Cuvier’s and Blainville’s beaked whales, both of them deep-divers like the sperm whales.
Sound is very important for these whales. In these waters where light is absent, whales have found a way to catch their prey. To do so, they use a biosonar, also called echolocation. With this biosonar, whales can find their prey, even in the dark. Echolocation acts like a series of instant flash photographs taken by sounds known as clicks. Clicks scan the area and the whale listens to the echo to visualize its surroundings. When the whale comes close to its prey, it starts clicking faster to update its location, switching from a photo mode to a video mode. Marine bioacoustics scientists call theses fast sounds “buzzes”.
A profitable sea for tourism, fossil energies and now deep sea mining
Although sperm whales spend most of their life deep below the surface, they face important human disturbances like noise pollution. The sea surrounding the Canary Islands where they live is caught in the middle of a controversy regarding its exploitation. When it comes to making political decisions, there seem to be two types of seas. The first is the profitable sea: it is the one that generates profits in the short term. Building hotels on the beachfront, marinas, or exploiting fossil resources via offshore oil rigs are some examples of this “profitable” sea’s current exploitation.
Rare minerals underwater
Deep-sea mining seems to be the next plan for the Canary Islands’ profitable sea. A few years ago, scientists found an incredible source of rare minerals like tellurium in what is called the Tropic Seamount close to the Canary Islands. Tellurium is used to make solar panels and it present in high concentrations in this seamount. It is interesting to think that in order to produce renewable energy, we plan to destroy the seafloor and species that rely on it to survive … Deep-sea mining requires the seabed excavation, which would cause an impact on all the whales in the area in part due to noise pollution.
Noise affects sperm whales
Exposure to loud noise can cause short-term intense responses in the whale’s body. The crazy loud noise can cause the whales to panic and rush towards the surface to breathe. When the whales try to surface too quickly, it can cause decompression sickness or “the bends” and can cause irreversible damage. Long term effects of noise pollution include the reduction of the whales’ fitness. Fitness is the capacity to survive and reproduce healthily.
The real profitable sea of the Canary Islands
The “unprofitable” sea is the one we need to protect; it includes marine life and its biodiversity. We need to make sure this biodiversity remains so one day you can come with your children to visit the Canary Islands and enjoy the some of the world’s largest toothed whales just a couple of hundred meters from the shore.
Although deep-sea mining has not started in the Canary Islands yet, multiple human activities threaten local whales, like sonar activities, vessel traffic, oil rigs, etc. Finding a compromise between the profitable sea and the protection of its biodiversity is essential. This ocean that some humans plan to destroy relies on a delicate balance that feeds human populations around the world. Sustainable development is essential to preserve this fragile balance and help the sea remain a somewhat healthy environment.
We cannot expect the most degraded areas to recover from one day to the next. Yet, the current COVID-19 global crisis has taught us that if we let our oceans breathe, we can see them recover with our own eyes. Noise reduction from the pandemic may allow some whales to catch a break and thrive in a quieter ocean. Maybe we should learn from this, let our oceans recover, and stop cashing in on finite resources that threaten our precious sperm whales.
Guerra, M., Dawson, S., Sabadel, A., Slooten, E., Somerford, T., Williams, R., Wing, L. & Rayment, W. (2020). Changes in habitat use by a deep-diving predator in response to a coastal earthquake. Deep Sea Research Part I: Oceanographic Research Papers, 103226.
Olivia is a 25 years-old student in marine biology, biodiversity, and conservation at La Laguna University (Canary Islands, Spain), working on marine bioacoustics in Sperm Whales. She is passionate about science communication and has her own YouTube channel and blog in Spanish.