This Hacker News thread discusses a report that China dominates 44% of visible global fishing activity. A key concern raised is the unreliability of AIS data, which is easily spoofed and manipulated, often falsely attributing activity to Chinese vessels. This makes accurate tracking difficult. The environmental impact of bottom trawling is highlighted, along with accusations of illegal fishing tactics by Chinese vessels, such as disabling transponders and encroaching on protected ecosystems. Concerns are raised about "dark fleets" operating unregistered and outside regulations. While some argue that China's dominance is problematic due to unregulated fishing practices, others point to China's significant aquaculture production as a more sustainable alternative. Counterarguments suggest that aquaculture relies on wild-caught fish for feed, shifting the problem rather than solving it. The discussion also touches upon the complexities of international fishing regulations, the need for marine reserves, and the potential for engineered fisheries.