SIMPLE carcass counting may have underestimated by 50 times the number of whales and dolphins killed by the Deepwater Horizon oil spill.
The from the US government鈥檚 task force states that 100 dead marine mammals have been collected in the Gulf of Mexico since the spill. But in such a vast area, many more bodies will never be found.
Recovered carcasses 鈥渞epresent the tip of the iceberg,鈥� says of the University of St Andrews, UK. 鈥淲e need a way to estimate the size of the iceberg.鈥�
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To prove his point, Williams and colleagues compared the number of carcasses found in the gulf each year with year-on-year estimates of marine mammal deaths produced by the US National Oceanic and Atmospheric Administration. They found that, on average, only 2 per cent of the mammals estimated to die each year are recovered (Conservation Letters, ). This suggests estimates of the impact of last year鈥檚 spill may be optimistic.