Kategorie: News
FRESH Protocol Aims to Make Cases Comparable
Since 2005, a pattern has repeatedly emerged in the U.S. and Australia: Following hurricanes, heavy rains, or floods, dolphins near the coast develop extremely painful skin lesions—comparable to severe burns. Experts refer to this as “freshwater skin disease” (FSD).
This condition develops when dolphins come into prolonged contact with heavily desalinated water, for example, because rivers push more freshwater into estuaries and bays after heavy rainfall, or because the animals remain trapped in such waters for extended periods.
The condition was first documented in a group of bottlenose dolphins that were trapped in a brackish water lake in Louisiana following Hurricane Katrina in 2005. The pathological basis was later established by a study led by veterinary pathologist Nahiid Stephens of Murdoch University in Perth, published in *Scientific Reports*: Osmotic stress damages the animals’ skin cells, leading to tissue necrosis and open ulcers—in some cases, up to 70 percent of the skin’s surface was affected. Bacterial, fungal, or algal infections often compound the condition, further worsening the situation.
The link to climate change is obvious to researchers: More frequent and intense rainfall in confined areas, as well as melting glaciers, are altering the salinity of many coastal waters more drastically and rapidly than dolphins can physiologically adapt. Cases from the Gippsland Lakes in Australia (2007) and the Swan-Canning River near Perth (2009) also followed periods of unusually heavy rainfall.
A Common Standard for Diagnosis
What was still missing from the early reports was a standardized method for reliably identifying and classifying such skin changes—various research teams had previously described similar symptoms inconsistently, making comparisons between regions and studies difficult. This is precisely where the FRESH protocol (Freshwater-Related Evaluation of Skin Health), published in 2026 in *Frontiers in Marine Science* and developed by an international team led by Kristi Fazioli, comes into play.
At its core, FRESH is an assessment system that allows even field biologists without medical training to use photos of freely swimming dolphins to identify whether typical signs of the disease are present: crusty or slimy coatings on the skin, ring-shaped “target lesions,” and unusually light, pale patches of skin. Based on these three characteristics, the protocol assigns a severity rating ranging from low to high. In tests, the assessments by field biologists and veterinarians corresponded surprisingly well—an important step toward documenting suspected cases worldwide according to the same criteria in the future.
The developers expressly emphasize that the protocol does not (yet) replace a diagnosis in the medical sense, nor does it allow for direct predictions about the survival chances of individual animals.
Its value lies primarily in making large photo databases systematically analyzable—for example, to understand how the disease develops or regresses over time, and how frequently dolphin populations are exposed to repeated freshwater contact. In light of increasing extreme weather events, this systematic monitoring is likely to gain importance in the coming years.
Sources:
Nonsprecare.it https://www.nonsprecare.it/de/SüÃwasserdelfinkrankheit
Frontiers in Marine Science (FRESH Protocol) https://doi.org/10.3389/fmars.2026.1743541