NASA’s Earth Observatory posted this image of the Korea and the Yellow Sea at night. The bright group of lights in the center is South Korea. China is the left third of the image and Japan is on the right. Why is the sea so well-lit, you might ask? Those are factory fishing operations.
The zoomed image below shows Korea still in the center, but China is mostly removed from the left side. The Yellow Sea is the open water between Korea and China. Most of those lights are factory fishing operations. It really gives you an idea of how large these operations are when groups of them show up almost as bright as the large cities of South Korea.
As many fishing boats as appear in that photo, the Yellow Sea fisheries are not as healthy as they used to be. It is considered one of the most overfished areas of the world. Catches declined severely between the 1960s and 1980s (as they did in much of the world), with larger, more economically viable fish virtually disappearing from the nets and being replaced with smaller, less desirable fish, such as anchovies. Pollution from development along the coastlines has also affected the ecosystem.
It’s easy to think of fisheries as being large numbers of 24 foot boats with four or five people from a family working them, but that’s clearly not what is in this photograph.