Increasing cormorants bleach Han River Island white

A big cleanup was held in Seoul`s Bamseom Island in the Han River for the first time in three years. At around 2 p.m. on Wednesday, two water cannons were blasted from the ship owned by Seoul Metropolitan Government`s Han River management unit toward the weeping willow forest in the southern part of Bamseom. The white weeping willows soon exposed their black bare skin. The reason they had turned white was because of droppings of common cormorants, birds that reside in Han River.

Such whitening phenomenon was first observed in 2011 when the excrement of cormorants increased explosively. There were 427 cormorants at Bamseom in 2010, which surged to 1,506 this year. Bird excrement contains highly acidic concentrates and they dyed the island (279,000 square meters) white.

Bird experts interpret the surging number of cormorants as a sign that the island`s ecosystem is recovering. Cormorants are huge birds whose body is more than one meter long, and they eat large fish like carp and cornet fish. "Bamseom is home to 32 fish species and there are also many old trees there where cormorants live," said Yoo Jeong-chil, biology professor at Kyung Hee University.

However, too many cormorants cause side effects. Last year, a huge number of cormorants suddenly flocked to a small island in Sokcho City, Gangwon Province, causing death of pine and bamboo trees. Han River water system fishermen are also raising concerns. "Cormorants` favorite food are eels that return from West Sea to Han River," said Park Chan-soo, chief at Haengjoo fisheries village. "Eel catch was cut to one third after the number of cormorants surged there."