Last updated March 6, 2017 at 1:53 pm
Bottlenose dolphins are well known for their interactions with humans in the waterways around Savannah, Georgia. This includes begging from recreational fisher boats and following trawlers to scavenge fish and by-catch. But not all dolphins follow trawlers suggesting that this may be a suite of learned behaviours passed on among smaller social groups according to a new study. The researchers also found that the different behaviours presented different risks to the dolphins and need to be managed differently.
The study published in PLOS ONE today focused on 137 non-calf dolphins that had been identified during photo-identification surveys on at least six field days. The researchers determined if the dolphins begged from fisher boats or followed trawlers. They also conducted a statistical analysis of how often individual dolphins were seen together to establish the size and make up of social groups. The study was conducted during three consecutive summers.
The researchers identified six social clusters of dolphins, half of which followed shrimp trawlers and half of which did not. This suggests that following shrimp trawlers may be a socially-learned behaviour. In contrast, begging and non-begging dolphins were spread across the clusters.
Co-author of the study Robin Perrtree commented, “Bottlenose dolphins interact with humans, which puts them at risk of injury or death. Risky behaviours, such as begging at recreational boats and interacting with shrimp trawls, are not the same and should not be treated as comparable by researchers and managers.”
- Link to original research article: journals.plos.org/plosone/article?id=10.1371/journal.pone.0170151