It not overfishing. Overfishing is when the regs say you can take X amount, but you take X+Y.
The Chinese take everything that enters their nets. Everything, leaving a lifeless desert. This is called rape of the seas.
Not only do the dump their trash, waste fish, and fish parts back, they also dump their raw sewage, turning the water a muddy brown. They do this systematically, then when the resource is gone, they move on to the next location.
IOW, China is treating South America's waters like they treat their own land and water...