Sobral Santos II

The September 20, 1981, shipwreck of the riverboat was one of the worst maritime tragedies in the history of the Amazon River. 
The riverboat was making its weekly trip between Santarém and Manaus and was claimed to be overcrowded when it sank in Óbidos harbour. It is assumed over 300 people died in the disaster, with hundreds of bodies and body parts never identified. Of 500 people estimated to have been aboard, at least 178 had survived as reported by the Captain, Elio Palhares, that day.
In 2014, British angler Jeremy Wade went to Óbidos to investigate the role that local fish species may have played in the loss of life during this disaster; his findings were documented in the "River Monsters" episode entitled "Amazon Apocalypse." After investigating numerous possibilities, including botos (river dolphins), caimans, and piranha, Wade concluded that the culprits were likely hordes of piraiba and redtail coda rossa catfish, drawn by chum from nearby fish processing operations, probably joined by the black piranha and other small carnivorous fish. He hypothesized that the large redtails and piraiba pulled the struggling victims underwater, where they drowned.