"Global fisheries face an existential threat in the decades ahead from surging worldwide demand, declining ocean health, and continued illegal, unreported, and unregulated (IUU) fishing. IUU fishing also harms legitimate fishing activities and livelihoods, jeopardizes food and economic security, benefits transnational crime, distorts markets, contributes to human trafficking, and undermines ongoing efforts to implement sustainable fisheries policies. It can also heighten tensions within and between countries and encourage piracy. The illicit nature of IUU fishing means that the size of the problem and its negative consequences, can only be roughly estimated. IUU fishing accounts for an estimated 15 to 30 percent of global annual catches, according to some studies. IUU fishing is prevalent because:  IUU fishing benefits from high demand.  The profits derived from IUU fishing substantially exceed the potential risks.  The skills required for most fishers to engage in IUU fishing are minimal.  The difference between legally and illegally obtained fish is hard to discern."
Office of the Director of National Intelligence: https://www.dni.gov/