A kerfuffle that is symptomatic of a much larger problem: overfishing.
China's rapid economic development has led them to a lot of unregulated harm, both to themselves and to others. In this case, we will likely see, in our lifetime, the collapse of some species of commercially important fish, if not entire marine ecosystems. We have already influenced evolution of some larger species of fish, making them smaller over time.
The ocean ecosystems are being stressed by increased warming, and CO2 buildup causing increases in acidification. Add in other forms of pollution, such as coastal runoff, plastics and so forth, and you have a recipe for some very serious problems, especially for countries that rely on wild fish for their primary protein source.
Bit of background reading on the issue, for those interested:
https://en.wikipedia.org/wiki/Tragedy_of_the_commons
http://overfishing.org/