Follow up to postings on the Gulf Coast oil spill, via National Geographic – “A 2009 stock assessment report by the National Oceanic and Atmospheric Administration (NOAA) estimated that the potential biological removal, or PBR, level for the Gulf of Mexico sperm whale population is three…The loss of a handful of whales each year can impact a population of hundreds, because sperm whales—especially females—require a very long time to reach sexual maturity. Females then give birth to just three or four calves during their entire lifetimes..Also, the fumes on the surface of the water after a recent spill can be powerful enough to knock out full-grown whales, causing them to drown.”