Picture a stingray. Is it 8 feet wide? Didn't think so, but that's the incredible size the giant freshwater stingray can grow to. Less incredible: More than 70 of the endangered fish have turned up dead in Thailand's Mae Klong River in recent weeks, reports National Geographic, and pollution is believed to be the culprit. For one thing, the fact that the stingrays' internal organs were destroyed "indicates toxic contamination of the water," reported the Bangkok Post in mid-October—when there were believed to be just 150 stingrays left in the river, per another Post article.
While it's possible the stingrays were poisoned by cyanide meant to kill other fish, officials believe the blame rests with an ethanol plant where a broken pipe caused wastewater containing high levels of ammonia to enter the river in late September, per the Post. "One thing is clear: a reduction of pollution from surrounding factories is needed to improve the health of the river and save the stingrays in the long term," a biology professor tells National Geographic. (A zoo accidentally killed more than 50 stingrays.)