Final answer:
Bluefin tuna are termed 'stateless fish' by Bestor because they traverse international waters, eluding the control of any single nation, and as a result, are overfished due to lack of effective international regulation.
Step-by-step explanation:
Bestor refers to bluefin tuna as "stateless fish" because they belong to an international commons and are not confined within a single country's borders. This presents a challenge for managing and regulating their catch, as they are highly migratory and fished by multiple countries. The tragedy of the commons is a situation where individuals, acting in their own self-interest, deplete a shared resource, making it unavailable for everyone. The International Commission for the Conservation of Atlantic Tunas (ICCAT) was created to manage and conserve tuna across countries but struggled with enforcement in its early years, highlighting the difficulty of managing stateless resources.