Each year, the number of stranded and dead porpoises turn around the 600 on the dutch coast. However, this summer, about 190 porpoises hist died on the Dutch Warren Islands, in a record 10 days. Researchers at Utrecht University and Wageningen University and Research conducted research into what could have caused these disturbing deaths.
The team was set up at the request of the Ministry of Agriculture, Nature and Food Quality to understand the situation. She worked on 22 porpoises, of which 16 females adults, all decaying. According to them, there is a good chance that they all died in the same period.
Further work has enabled them to detect the presence ofErysipelothrix rhusiopathiae. It’s about a bacterium known to be toxic for fish.
Toxic algae perhaps?
The first stage of the research consisted of taking blood for analyzes. Then there was the study of the physical condition of porpoises. Finally, we had to check for the presence of parasites.
After that, the researchers went to the labs to find out what would be inside these cetaceans. The aim was to find any harmful algae can kill them and the presence of others organizations harmful.
At the end of the various researches, the results had indicated that the majority of these fish were in good health before their death. According to the biologist Lonneke IJsseldijk from Utrecht University:
“They had a healthy fat layer, relatively few parasites, and many adult females had recently become pregnant. Therefore, sudden death seems obvious. “
Although they were mostly in good health, they suffered from fairly serious and acute illness caused by hunger. Indeed, the stomachs of the porpoises contained nothing. Others had eaten, but in small quantities.
Blood poisoning as a hypothesis
THE’Erysipelothrix rhusiopathiae was present in the majority of the sample. This bacteria frequently attacks pigs, turkeys, humans and fish.
The porpoises may have been infected by water, sick fish, or contamination. Strangely enough, this harmful substance had never been observed in these animals before. Enough to cause some panic in the scientific community!
The whole study was carried out as quickly as possible, after having considered and sorted the different theories.