Started in 2005, the contest has grown in popularity, with over 700 entries submitted this year, according to university scientist and contest judge Jiangang Luo.
"All the pictures we got were large, and high quality," said Luo. "It was a really tough job to narrow it down to a few."
The contest is open to any photography enthusiast, as long as they earn less than 20 percent of their income taking pictures. This year, entries came from all over the globe, with submissions from 23 countries. Categories include macro, wide angle, fish or marine animal portrait, and student work. (Get National Geographic's underwater-photography tips.)
Luo said that he and his fellow judges—photographer and university lecturer Myron Wang and underwater photographer Nicole Wang—unanimously agreed on the seal photo because it stood out from the others.
"The organizers would flash the photos in front of us," he explained, "and when that one showed up it caught all of our attentions."