This image, released in September 2012 in response to a 2010 freedom of information act request, shows NOAA staff investigating the carcass of a dead sperm whale in the Gulf of Mexico on 15 June 2010, seven weeks after the start of the BP Deepwater Horizon oil spill disaster. There were believed to be about 1,200 sperm whale in the Gulf of Mexico at the time of the spill, making it one of the biggest populations in the world

Photograph: NOAA