There are many issues attached to the fishing industry: overfishing, bycatch, pollution, fish farming, and economics. This is why it is so vital to protect the fish and other marine life populations in the ocean. If the IPCC can determine and enforce sustainable fishing quotas the ocean will be well protected. But since the ocean is a global commons and there is no full authority over it regulations are difficult to make. Additionally, since the ocean covers the majority of our planet there is no way to actually enforce these regulations and ensure people/fishing companies are following them. There is one company called Seashepard that acts like a vigilante group which boards boats that are engaging in suspicious activity. Since the ocean is so vast it is also difficult to determine quotas since it is hard to figure out exact population numbers. Scientists often are estimating the population sizes of species and even then fishing companies still push for higher quotas. Even with bycatch and fish farming quotas have to be set. Bycatch because it is the unnecessary catching and killing of marine life while fishing. Fish farming because often fish caught from the ocean are used as feed for the farm bred fish. Additonally, the usage of sustainable fishing methods in terms of techniques used like long lines, and trollers. So in terms of mathematics there is a lot of estimating involved with fishing to establish effective quota levels that protect populations and encourage sustainable economic activity. There is an interesting documentary on Netflix called Seaspiracy that explains all the dynamics of the fishing industry. When buying fish look to see if it was locally sourced or fished sustainably and consumption is the driving force for the fishing industry so it’s important to support environmentally conscious brands.