Cetacean strandings frequently let scientists interrogative: noise pollution, disorientation problem, illness, suicide?
A study conducted by the University of Aberdeen scientists and by the Scottish Marine Animal Stranding Scheme on a group of stranded pilot whales in 2012 in Fife sheds new light on these repeated strandings recorded around the globe.
Published in the journal Science of the Total Environment, the report showed a “clear” correlation between the increased levels and the age of the mammals, suggesting toxic stress increases the longer the mammals live.
They said this could demonstrate that this species of marine mammal was less susceptible to mercury poisoning than humans, but they could not entirely discount the possibility that it was a factor leading to whales navigating off course.
The level of mercury in the whales increased in correlation to the age of the mammals
The scientific team was able to gather an unprecedented number of tissue samples from all the major organs, including the brain, and as a result they can see for the first time the long-term effects of mammalian exposure to the environmental pollutants.
Analysis of samples revealed that the level of mercury in the whales increased in correlation to the age of the mammals, which ranged from under a year to 36 years.
The scientists found very high concentrations of mercury in the brain of all the whales older than nine years and in three the concentration was higher than levels at which severe neurological damage would occur in humans.
The scientists said there was no indication that the mercury and cadmium levels in the brain caused disorientation, which in some cases can lead to strandings, but there was a potential for higher stress in the whales.
