Threats to Cetaceans

While the persecution of some whale species, such as humpbacks and blue whales, has reduced as whaling has declined, others are still under threat from a range of factors. Dead whales washed up in Asia starved and dehydrated because their stomachs are full of plastic. In Europe, killer whales are carrying dangerously high levels of banned PCB chemicals in their blubber, most likely bio-accumulated, as killer whales are apex predators in a long food chain. Pollutants are suspected for causing the death of five sperm whales that became stranded on the East Coast of UK

Exxpedition, Round Britain 2017, the last sailing expedition I took part in, set out to investigate the levels of micro plastics in British coastal waters: micro plastics attract persistent organic pollutants such as PCB’s, effectively concentrating the chemicals. The micro plastics then became part of the micro organism ‘soup’ which sustains the marine food chain (and ultimately human beings too).

This expedition, Joint Warrior, will be investigating a very different type of pollution, but potentially equally damaging to cetaceans. Sound pollution.

The ocean is a world of sound, not sight.  Marine mammal species perceive the sounds of sonar as a threat and react accordingly. Noise emanating from passing ships may disturb animals such as killer whales and dolphins far more than previously thought, with new research showing that the animals’ communication and ability to find prey could be hampered by the underwater din.

UK’s last resident killer whales 'doomed to extinction'?

There are several knock-on consequences of a noisy marine environment. Whales may have to group together more closely in order to hear each other. Consequently they occupy less marine ‘space’ and so have access to less prey. And should they fail to find prey as effectively, they will need to use up their stores of excess blubber which often contains manmade pollutants such as PCB’s. These are toxic to whales if released fully into their systems.

The mass stranding of 39 long-finned pilot whales in 2011 in Scotland and a group of common dolphins stranding on the shores of Cornwall in 2008. In both of these cases a government report later revealed that the likely reason for the mass stranding was naval underwater detonations.

More work needs to be done to identify how badly the noise is affecting whales and also to quieten the ships that pass near the cetaceans in order that more work will be done to restrict noise pollution in the sea. For example decreasing  speed by six knots could decrease noise intensity by half.

In the UK there are some regulations and limitations in place already. These include regularly assessing possible cetacean habitats, ways of minimising impact on marine wildlife in Royal Navy’s basic training and increasing the intensity of sonar gradually so that the animals can begin to move away from the unpleasant sound. Furthermore, assessments of the impacts of different sources of noise to marine life and the identification of important cetacean habitats, breeding grounds and migration routes are done regularly.

The Royal Navy is now required to turn off sonar systems if animals are in the area and are banned from using pulses higher than 180 decibels within 22.5 kilometres (14 miles) from coasts, especially coastlines belonging to 'biologically important' areas. However, while no one is saying that the Navy is disobeying their current policy, a new ruling states that the regulations currently in place are not doing enough to protect the sea’s creatures and that new rules and guidelines need to be put in place.