Bottlenose dolphins: Last pod in England at serious risk of extinction due to pollution and fishing

England’s last pod of “highly intelligent” bottlenose dolphins are at serious risk of extinction due to human activity, environmental pollution and difficulties in rearing young that survive into adulthood, according to new research. The researchers estimate that the pod currently consists of just 48 dolphins, which is less than half the size of most coastal bottlenose dolphin populations, and around 10 times smaller than a pod known to inhabit the Channel coast of France.

Dr Simon Ingram, who leads the bottlenose dolphin research project and is senior author on the study, said bottlenose dolphins are “highly intelligent and social animals with complex cultures” adding that that they are “known to have some of the closest interactions with humans of any species on the planet, but because they live in the sea, and not on land, they go unseen by most people and we fail to appreciate quite how amazing yet vulnerable they are.” He added that to see “the south coast population decline to extinction would be a local tragedy for the dolphins and for us.”

For almost a decade, scientists and conservation groups based along the English Channel coast have been working together with citizen scientists to monitor the movements and distribution of this population, enabling them to establish the most detailed picture yet of their movements and social interactions - as well as the challenges they face on a daily basis. The research is being led by Cornwall Wildlife Trust and scientists at the University of Plymouth to collate and analyse sightings data, through the South Coast Bottlenose Dolphin Consortium.

The study is the result of work by former marine biology research student Shauna Corr, and former marine conservation students Rebecca Dudley and Saskia Duncan, supervised by Dr Ingram. The findings have led the researchers to call for urgent measures to protect the population and its habitats, or risk the possibility that this group of animals may not survive.

The bottlenose dolphin’s fight for survival is made even more challenging by the fact they inhabit some of the busiest shipping lanes in the world and also coastal waters known to suffer from repeated and prolonged spells of pollution and fishing pressure.

The findings have led the researchers to call for urgent measures to protect the population and its habitats, or risk the possibility that this group of animals may not survive. The repeat sightings revealed that dolphins from this pod travel the coast between North Cornwall and East Sussex, with some individuals known to have travelled up to 760km between sightings. The population appears to be isolated with individuals known to socialise within their own pod close to the shore but not with others from other populations normally found in the open sea.

This population of bottlenose dolphins was first documented by scientists in the mid-1990s and became the subject of detailed scientific analysis again in 2017 due to concerns raised by Cornwall Wildlife Trust about their plight and vulnerability to human impacts. Individual bottlenose dolphins can be identified from their unique fin markings enabling scientists to build up a catalogue of known dolphins which, through repeated sightings, helped the students to track the movements of individual animals over several years. The study’s authors hope the information will be used by statutory marine conservation organisations to provide better protection for this highly vulnerable population and to take appropriate measures in order for the pod to survive.