New research suggests that the Buddhist ritual has resulted in an all-you-can-eat buffet for otters that live near rivers on the Tibetan Plateau.

“Fangsheng,” meaning life release, is a religious practice of releasing and saving animals that were to be killed. Buddhist texts advocate the approach as a means of “paying back debt,” “erasing bad luck… healing illness,” and “extending one’s life,” in addition to other benefits, as per an article published by The International Journal of Interreligious and Intercultural Studies.

According to this tradition, Buddhists living on the Tibetan Plateau in southwestern China have been releasing fish that they purchase from markets in local rivers from at least the late 1990s; according to a study published on June 21 in The Current Zoology discovered that otters have developed a liking for the freshly released fish.

“Religious fish release may provide additional food resources for otters,” researchers have written in their study. The fish released are generally exotic and non-native species like Crucian carp (Carassius carassius) and common carp (C. carpio), which could carry diseases or challenge indigenous species to get resources. The study found that local authorities banned the release of non-native fish into the wild in 2019. However, the population was largely ignorant of the ban.

Despite the thousands of fish released each year, scientists discovered only a few in the local waters, including only two carp from the crucian species in samples collected during the spring and autumn of 2019. According to the study, The species has successfully invaded and established populations across the Tibetan Plateau.

‘Adventurous consumers’

Researchers noted that Eurasian Otters ( Lutra lutra) are top predators and “adventurous consumers” who don’t hesitate to explore novel food options. To find out if they are eating traditional fish species, the group analyzed otter feces samples from the banks of rivers in which the fish are released.

The study found that although they comprised a small percentage of the fish available, non-native species included 20 percent of the prey in otter poop. This suggests they prefer ritual fish instead of natural species. “Eurasian otters showed a preference for released fish,” the study’s authors said. The study authors suggest that by hunting exotic fish, the otters could reduce the adverse effects of Fangsheng and prevent non-native species from settling in the river’s ecosystem.

Otters may not pick released fish for flavor but because they’re simple to catch.

The low-oxygen, cold conditions in the Tibetan Plateau are harsh for exotic species transported to lower altitudes. Rising 14,800 feet (4,500 meters) above sea level, the plateau is often referred to as the “roof of the world,” according to NASA’s Earth Observatory. This means that released fish might not be able to swim as quickly as native fish, researchers concluded.

“Another reason may be that non-native fish have higher nutrition and energy, which needs to be studied further,” the authors have written. The research team looks forward to studying the role of Otters in removing released fish by keeping predators out of the river.