Scientists from the largest marine mammal hospital in the world, The Marine Mammal Center in Sausalito, California, and their international colleagues have discovered a rare skin condition in dolphins that is related to climate change.
The study is a ground-breaking discovery since it is the first time since the illness initially surfaced in coastal dolphin groups around the world in 2005 that researchers have been able to pinpoint a cause.
Due to the decreased water salinity brought upon by climate change, the dolphins develop patchy and raised skin lesions across their bodies sometimes covering upwards of 70 percent of their skin.
The international study, which can be found here, was co-authored by three internationally respected scientists, from California and Australia:
- Dr. Pádraig Duignan, Chief Pathologist at The Marine Mammal Center
- Dr Nahiid Stephens, a veterinary pathologist at Murdoch University (Perth, Australia)
- Dr. Kate Robb, Founding Director, zoologist, and geneticist of the Marine Mammal Foundation (Victoria, Australia)
The study offers the first-ever case definition for fresh-water skin disease in bottlenose dolphins and was published in the peer-reviewed journal Scientific Reports in the field of natural sciences. Following substantial outbreaks in recent years in Louisiana, Mississippi, Alabama, Florida, Texas, and Australia, this investigation was conducted.
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.
Dr. Pádraig Duignan
The common feature among all of these places was a fast, sharp decline in the salinity of the waterways. Although they don’t dwell in freshwater, coastal dolphins are used to seasonal variations in the salinity levels in their maritime home.
As hurricanes and cyclones become more severe and frequent, and especially when they are preceded by dryness, they are pouring unprecedented amounts of rain that convert coastal waters to freshwater.
Particularly following powerful storms like hurricanes Harvey and Katrina, freshwater conditions can last for months. Climate scientists have predicted that as temperatures rise, strong storms like this would happen more regularly, leading to more frequent and severe disease outbreaks among dolphins.
“This devastating skin disease has been killing dolphins since Hurricane Katrina, and we’re pleased to finally define the problem,” said Duignan.
“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.”
The study could give experts the knowledge they need to detect and treat infected animals. The discovery has significant implications for the current outbreak in Australia, which is affecting the endangered and threatened Burrunan dolphin in southeast Australia.
The long-term prognosis for dolphins with the skin illness is currently not good. This is especially true for animals that have been exposed to freshwater over an extended period of time.
After Hurricane Katrina in 2005, researchers discovered the fatal skin condition on about 40 bottlenose dolphins near New Orleans.
“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,” said Duignan.
“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.”
