Navigation Links
Whale and dolphin death toll during Deepwater disaster may have been greatly underestimated
Date:3/29/2011

The Deepwater Horizon oil spill of 2010 devastated the Gulf of Mexico ecologically and economically. However, a new study published in Conservation Letters reveals that the true impact of the disaster on wildlife may be gravely underestimated. The study argues that fatality figures based on the number of recovered animal carcasses will not give a true death toll, which may be 50 times higher than believed.

"The Deepwater oil spill was the largest in US history, however, the recorded impact on wildlife was relatively low, leading to suggestions that the environmental damage of the disaster was actually modest," said lead author Dr Rob Williams from the University of British Columbia."This is because reports have implied that the number of carcasses recovered, 101, equals the number of animals killed by the spill."

The team focused their research on 14 species of cetacean, an order of mammals including whales and dolphins. While the number of recovered carcasses has been assumed to equal the number of deaths, the team argues that marine conditions and the fact that many deaths will have occurred far from shore mean recovered carcasses will only account for a small proportion of deaths.

To illustrate their point, the team multiplied recent species abundance estimates by the species mortality rate. An annual carcass recovery rate was then estimated by dividing the mean number of observed strandings each year by the estimate of annual mortality.

The team's analysis suggests that only 2% of cetacean carcasses were ever historically recovered after their deaths in this region, meaning that the true death toll from the Deepwater Horizon disaster could be 50 times higher than the number of deaths currently estimated.

"This figure illustrates that carcass counts are hugely mis-leading, if used to measure the disaster's death toll," said co-author Scott Kraus of the New England Aquarium "No study on carcass recovery from strandings has ever recovered anything close to 100% of the deaths occurring in any cetacean population. The highest rate we found was only 6.2%, which implied 16 deaths for every carcass recovered."

The reason for the gulf between the estimates may simply be due to the challenges of working in the marine environment. The Deepwater disaster took place 40 miles offshore, in 1500m of water, which is partly why estimates of oil flow rates during the spill were so difficult to make.

"The same factors that made it difficult to work on the spill also confound attempts to evaluate environmental damages caused by the spill," said Williams. "Consequently, we need to embrace a similar level of humility when quantifying the death tolls."

If the approach outlined by this study were to be adopted the team believe this may present an opportunity to use the disaster to develop new conservation tools that can be applied more broadly, revealing the environmental impacts of other human activities in the marine environment.

"The finding that strandings represent a very low proportion of the true deaths is also critical in considering the magnitude of other human causes of mortality like ship strikes, where the real impacts may similarly be dramatically underestimated by the numbers observed" said John Calambokidis, a Researcher with Cascadia Research and a co-author on the publication.

"Our concern also applies to certain interactions with fishing gear, because there are not always systematic data with which to accurately estimate by-catch, especially for large whales", noted Jooke Robbins, a co-author from the Provincetown Center for Coastal Studies. "When only opportunistic observations are available, these likely reflect a fraction of the problem."

"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," concluded Dr. Williams. "We now urge methodological development to develop appropriate multipliers so that we discover the true cost of this tragedy."


'/>"/>

Contact: Ben Norman
Lifesciencenews@wiley.com
44-012-437-70375
Wiley-Blackwell
Source:Eurekalert

Related biology news :

1. Researchers discover new wintering grounds for humpback whales using sound
2. Oil giant plans new platform near feeding ground of critically endangered whale
3. Colossal fossil: Museums new whale skeleton represents decades of research
4. Blue whale-sized mouthfuls make foraging super efficient
5. Fleshing out the life histories of dead whales
6. Whale-inspired ocean turbine blades
7. Whale sharks do the math to avoid that sinking feeling
8. Researchers find first genetic evidence for loss of teeth in the common ancestor of baleen whales
9. Critically endangered whales flee Russian oil, gas boom
10. Whale sharks may produce many litters from 1 mating, paternity test shows
11. Blue whales align the pitch of their songs with extreme accuracy, study finds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:11/21/2016)...   Neurotechnology , a provider of high-precision ... that the MegaMatcher On Card fingerprint matching algorithm ... NIST Minutiae Interoperability Exchange (MINEX) III ... of the evaluation protocol. The ... fingerprint templates used to establish compliance of template ...
(Date:11/15/2016)... 15, 2016  Synthetic Biologics, Inc. (NYSE MKT: ... on the gut microbiome, today announced the pricing ... of its common stock and warrants to purchase ... price to the public of $1.00 per share ... from the offering, excluding the proceeds, if any ...
(Date:6/22/2016)... 2016  The American College of Medical Genetics and Genomics ... as one of the fastest-growing trade shows during the ... Bellagio in Las Vegas . ... growth in each of the following categories: net square feet ... of attendees. The 2015 ACMG Annual Meeting was ranked 23 ...
Breaking Biology News(10 mins):
(Date:11/30/2016)... 30, 2016  The Allen Institute for Cell ... first publicly available collection of gene edited, fluorescently ... key cellular structures with unprecedented clarity. Distributed through ... tools are a crucial first step toward visualizing ... what makes human cells healthy and what goes ...
(Date:11/30/2016)... Nov. 30, 2016  Tempus, a technology company ... and Penn,s Abramson Cancer Center have partnered to ... response to immunotherapy treatment based on next generation ... part of a research collaboration, Tempus will provide ... cancer patient data to Penn. Utilizing next-generation sequencing, ...
(Date:11/30/2016)... 2016   Merck , ein führendes ... einer Reihe von Vereinbarungen mit Evotec AG ... Screeningleistungen für Mercks Palette genetischer Reagenzien wie ... diese Bibliotheken in Kombination mit Evotecs Expertise ... zur Ermittlung und Erforschung neuer Arzneimitteltargets.    ...
(Date:11/30/2016)... BILLERICA, Mass. , Nov. 30, 2016   ... announced that it has entered into a set of ... screening services for Merck,s collection of genetic reagents such ... libraries with Evotec,s screening expertise offers an accelerated pathway ... "Drug discovery starts with the identification of new targets, ...
Breaking Biology Technology: