Satellite images uncover mystery of 275 rare dolphin deaths
There were extinction fears after rare pink dolphins began to die in lakes on the Amazon River. Experts in satellite analysis were determined to work out why.
Satellite images have been used to investigate the cause of a tragedy that resulted in hundreds of dolphin deaths. Analysis has revealed several likely human and weather related events contributed to the disaster.
As the incident began to unfold a year ago along the Amazon River Yahoo News spoke regularly with Sea Shepherd Brazil as it documented the deaths on the ground. Its president Nathalie Gil was sure humans had played a role in the catastrophe, but she was unsure how.
At least 275 dolphins were reported dead, including 178 rare pink river dolphins — roughly 10 per cent of the entire species. “Before this stress happened we worried they probably could disappear in three decades, so with this threat on top it could be faster,” she told Yahoo in October.
Responding to concern from conservationists, experts from EOS Data Analytics, a company that specialises in satellite data interpretation, used niche software ordinarily used to monitor crops and forestry to determine what killed the dolphins, and released a report this week.
It used the tools to examine images of the basins of Lake Tefé and Lake Coari where the majority of deaths occurred, looking at dramatic changes to the water.
What did the satellite images reveal?
EOS Data Analytics found the perimeter of Lake Tefé had dramatically shrunk and become shallower because of drought, and an algal bloom was also detected. Around 170 km southeast at Lake Coari the problem was similar, except the algae was so severe the vegetation reading matched those of nearby forests. Sadly the problem persisted even after the lakes began to fill again.
On top of the drying of the lakes the temperature was also a problem. Analysis found the waters were a “hostile environment” for the dolphins, chiefly because of lower humidity and warmer conditions.
What killed the Amazon's dolphins?
The results have helped refine two theories about factors likely contributing to the dolphin deaths. The first is that temperature stressed the dolphins' physiological limits.
The other factor is that an algal bloom, although not directly harmful to the dolphins themselves, may have poisoned their main food source — fish. Consuming them could have resulted in the dolphins dying.
A third contributing issue has been chronicled on the ground, rather than using satellite data. And that's the likely impact of fishermen.
They accidentally kill dolphins with nets and also intentionally target them to butcher their flesh for use as bait. Analysis of the bodies found 10 per cent had signs of mutilation, harpoon marks, or net entanglement.
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EOS Data Analytics spokesperson Viktoria Troiian said ongoing monitoring will be crucial for helping to understand and mitigate the problems impacting the environment.
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