Oil spill wildlife impact estimate off

VICTORIA, British Columbia, March 30 (UPI) -- The impact of the 2010 Deepwater Horizon oil spill disaster on wildlife may be gravely underestimated, a study by Canadian researchers concluded.

The study by scientists at the University of British Columbia and elsewhere argues that fatality figures based on the number of recovered animal carcasses do not give a true death toll, which may be 50 times higher than believed, a report in the journal Conservation Letters said Wednesday.

Marine conditions and the fact that many deaths will have occurred far from shore means recovered carcasses will only account for a small proportion of deaths, the study said.

An analysis of species mortality rates and carcass recovery rates suggest only 2 percent of cetacean carcasses were ever historically recovered after their deaths in the gulf region, researchers said.

"This figure illustrates that carcass counts are hugely misleading, if used to measure the disaster's death toll," co-author Scott Kraus of the New England Aquarium said.

"No study on carcass recovery from strandings has ever recovered anything close to 100 percent of the deaths occurring in any cetacean population," he said. "The highest rate we found was only 6.2 percent, which implied 16 deaths for every carcass recovered.

"While we did not conduct a study to estimate the actual number of deaths from the oil spill, our research reveals that the accepted figures are a grave underestimation," Williams said.