Fishing communities are severely hurt as fish stocks collapse. The consequences of that also include increased migration to Spain's Canary Islands in search of work. Pursuing illegal fishing is extremely hard, but there's much more interest from states than others in doing it because after all, illegal fishing destroys livelihoods of many local communities. Many countries subsidize their fishing fleets and China is the biggest subsidizer. For instance, deep sea bottom trawling wouldn't be viable without diesel subsidies for building new vessels.