Friday, December 27, 2013

Piranha Frenzy or just Media Frenzy?

Piranhas did not "attack" 70+ people in Argentina on Christmas day in a feeding frenzy; the only frenzy here is the news medias desire to report this story (ABC, Fox, Discovery, BBC, etc. have all reported it). From what I can gather, several people, one a young girl, were bitten in the Parana River near Rosario, Argentina. Some people may have lost parts of (and perhaps entire) digits according to some of the reports. The Parana River does have piranhas but none at the scene said it was piranhas, but rather ‘palometas.’ Piranhas in a feeding frenzy can consume animals as large as humans in seconds, but they are very picky about their food source and reports of human attacks are few (see paper here). Most people who lose a finger to a piranha have lost it after mishandling it on a hook or in a net out of the water. Piranhas in a frenzy will take off more than your finger tip. Several news agencies report the fishes are “palometas’ and show images or mention a common species of jack; however, all jacks are marine so they wouldn’t be in the freshwaters of the Parana River. Pygocentrus palometa was described as a Venezuelan piranha species that is likely not a valid species (see Catalog of Fishes), and not known from Argentina. My guess is a few people were bitten by other biting tetras common to the area (Hoplias?); these bites may have scared lots of other people out of the water.

[UPDATE: I do think these were piranha bites now, having talked to some fellow ichthyologists. These were probably defensive bites from one of the local species they call palometas - Serrasalmus maculatus, S. spilopleura, or Pygocentrus nattereri]

Piranha 3D is a great movie, but it is not real.

Given the high temperatures of the day perhaps more people were bathing than usual and if the area is dammed, as much of the Parana is, the fish may have felt trapped, especially if breeding. These fishes were likely biting as a defense from the many people in the crowded water. If piranhas want to eat something, they will do so quite thoroughly, they won't peck. They will bite to protect themselves and that is not what I would call an "attack."

How this became an international media story is another mystery, but the name of the river likely caused some to guess that piranhas were the culprits. That, and some good pics of people with bloody toes.

Unfortunately, it does sound like some people were hurt, I hope they recover quickly. However, the news media should be accountable for the many errors in this sensationalized story.