Fatal skin disease in dolphins linked to climate change
A fatal skin disease affecting dolphin communities across the globe has been linked to climate change.
In a groundbreaking study, published in the journal Scientific Reports, scientists provide the first-ever case definition for freshwater skin disease in bottlenose dolphins.
They conclude that the increasing severity of storms has led to a drastic decline in water salinity, causing patches and raised skin lesions covering up to 70 per cent of a dolphin's body.
It is the first time that scientists have been able to find a link to the condition, which first appeared in 2005. Scientists hope that the discovery could provide professionals with the information they need to diagnose and treat affected animals.
The study was conducted by the Marine Mammal Center, California, in collaboration with researchers at the Murdoch University, Perth, and the Marine Mammal Foundation, Victoria.
Dr Pádraig Duignan, a chief pathologist at The Marine Mammal Center, said: “As warming ocean temperatures impact marine mammals globally, the findings in this paper will allow better mitigation of the factors that lead disease outbreaks for coastal dolphin communities that are already under threat from habitat loss and degradation.
“This study helps shed light on an ever-growing concern, and we hope it is the first step in mitigating the deadly disease and marshalling the ocean community to further fight climate change.”
The deadly skin condition was first noted in bottlenose dolphins following Hurricane Katrina in 2005. In recent years there have been significant outbreaks in Louisiana, Mississippi, Alabama, Florida, Texas and Australia.
Researchers found that in all of these locations, a sudden a drastic fall in water salinity was the common factor. While dolphins are accustomed to seasonal changes in salinity levels, they do not live in freshwater.
The study concludes that more intense storms are dumping unusual volumes of rain that turn coastal waters to freshwater. Such conditions can persist for several months, especially after events like hurricane Katrina, they note.
Scientists predict that as climate temperatures increase, storms like these will occur more frequently, and lead to more severe outbreaks in dolphins.
Dr Duignan said: “This devastating skin disease has been killing dolphins since Hurricane Katrina, and we’re pleased to finally define the problem. With a record hurricane season in the Gulf of Mexico this year and more intense storm systems worldwide due to climate change, we can absolutely expect to see more of these devastating outbreaks killing dolphins.”