La verdad no vale nada al lado del petróleo: se fraguan descaradamente las cifras de mamiferos marinos muertos por desastre del Golfo
Whale and dolphin death toll during Deepwater disaster may have been greatly underestimated.
La verdad no vale nada al lado del petróleo: se fraguan las cifras descaradamente y donde debe decir 5,000 se pone 100. A este paso vamos a tener que matar ballenas y delfines y tirarlos en la playa para que las estadisticas PINOCHO no se salgan del promedio
La cifra se ha subestimado de forma escandalosa. No fueron cien, sino varios miles los cetáceos muertos a consecuencia del nefasto derrame del Golfo de México. Concretamente, el número de ballenas víctimas de la marea negra habría superado los 5.000 ejemplares, revela un nuevo estudio.
Un año después del desastre ecológico provocado por la explosión de Deepwater Horizon, la plataforma de BP en el Golfo de México, nos enteramos de que las consecuencias para los cetáceos fueron bastante peores de lo que creíamos. Según una investigación publicada en la revista Conservation Letters, las 101 ballenas muertas son sólo una pequeñísima parte de las víctimas.
Los investigadores proponen una cifra más elevada que la reconocida hasta ahora por los científicos, pues entienden que recuperar los cuerpos de los animales suele ser misión imposible, apuntando que éstos pueden morir tanto en la costa como mar adentro, lo que dificulta el recuento.
El trabajo logra demostrar con datos que en este tipo de catástrofes lo habitual es encontrar los restos del 2 por ciento de los esqueletos. Por lo tanto, la cifra resultante superaría los cinco millares de ballenas y delfines fallecidos.
Más de 5.000 cetáceos murieron por el derrame del Golfo de México31 Mar 2011 ... No fueron cien, sino varios miles los cetáceos muertos a ... publicada en la revista Conservation Letters, las 101 ballenas muertas son sólo ...
www.ecologiablog.com/.../mas-de-5000-cetaceos-murieron-por-el-derrame-del-golfo-de-mexico - En caché
Conservation Letters: Whale and dolphin death toll during Deepwater disaster may have been greatly underestimated by Dr. Rob Williams, et al.
Animal Carcasses Recovered Represent a Small Fraction of Fatalities
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 misleading, 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.”
This study is published in Conservation Letters. Media wishing to receive a PDF of this article may contact Lifesciencenews@wiley.com
Full citation: Williams. R, Gero. S, Bejder. L., Calambokidis. J, Kraus. S, Lusseau. D, Read. A, Robbins. J., “Underestimating the Damage: Interpreting Cetacean Carcass Recoveries in the Context of the Deepwater Horizon/BP Incident”, Conservation Letters, Wiley-Blackwell, March 2011, DOI: 10.1111/j.1755-263X.2011.00168.x
Special thanks to Richard Charter