Heart-breaking footage shows a dead sea turtle tied up to a ghost net.

Scuba diving instructor Younggun Lee, 37, encountered the heart-wrenching scene while diving in the Sea of Japan off the coast of South Korea.

Younggun was coming up to the surface and was approximately five meters deep when he came across the dead sea turtle.

Younggun, a scuba diving instructor and freediving trainer, said: "I was shocked and didn't know how to react."

"This video is more than just one individual death. "

"It highlights the myriad of issues faced by marine creatures like sea turtles."

"That day, we not only saw a dead sea turtle but also various types of fish and clothing caught in the net."

"I shared the video in the hope that more people will be interested in protecting marine life."