Connectivity in dolphin DNA may support conservation plans

Atlantic white-sided dolphins have been shown to be highly interconnected within their population, challenging the common assumption of divided groups in cetacean species.

Genetic insights could help develop conservation strategies for the most common dolphin species in the North Atlantic.

A study of Atlantic white-sided dolphins is the first to reveal genetic links across the range of any North Atlantic dolphin species that is normally divided into distinct populations.

While most dolphin species are restricted to smaller areas and have separate populations, Atlantic white-sided dolphins are linked in a large population over a wide territory.

Given this difference, a blanket conservation plan for all cetacean species in the Atlantic may not be appropriate, according to the research team led by the Roslin Institute and the Royal (Dick) School of Veterinary Studies.

Dedicated teams monitored coastal areas of Scotland, Ireland, the Faroe Islands, Iceland, Norway and France for stranded dolphins. They collected genetic data from muscle and skin tissue samples and stored it over a 27-year period.

The samples were analysed by comparing them to DNA datasets representing important genetic markers without analysing the entire genetic code.

Long-term collections of stranding data are highly valued by cetacean researchers because they can provide insight into the effects of conservation management.

The results provide valuable insight into a species whose offshore habitat is often difficult to access and monitor.


Population structure and conservation

These results reveal previously unexplored aspects of Atlantic white-sided dolphin population structure and have implications for conservation measures for this species.

Protection of a population that spans a vast area would require communication among all relevant countries and management entities to agree on conservation efforts.

While genetic connectivity of a large population is generally a positive sign for the long-term health of the Atlantic white-sided dolphin, there is a lack of baseline data on genetic diversity and overall threats to the survival of individual animals, as well as regular monitoring of population health. Future conservation efforts should consider the unique structure of the species and adapt conservation plans to fit the specific structure of this dolphin species.

Institutions working to protect cetaceans could use these findings as a catalyst for further research into this largely understudied species, the team suggests.

The study was published in the ICES Journal of Marine Science. The research was conducted in collaboration with colleagues from the University of Glasgow, the Faroe Marine Research Institute (Faroe Islands) and the Irish Whale and Dolphin Group. The project was funded by a PhD studentship from the Royal (Dick) School of Veterinary Studies and the Roslin Institute.

Conservation management efforts should focus on monitoring genetic diversity, contaminant loads such as harmful industrial chemicals and other known threats for Atlantic dolphin species such as possible fishing bycatch. More information on the general distribution of Atlantic white sided dolphins is also needed. It’s important to research this deep sea associated species, there’s still much work to be done to understand how best to manage their conservation.