Final answer:
The Atlantic mackerel dispute led to conflicts and had implications for the fishing industry in the Atlantic Ocean. Overfishing and environmental changes threatened various fish stocks. The European Union and the International Commission for the Conservation of Atlantic Tunas implemented measures to address these issues.
Step-by-step explanation:
The Atlantic mackerel dispute sparked conflicts and had significant implications for the fishing industry in the Atlantic Ocean. Overfishing and changing environmental conditions posed a threat to the stocks of Atlantic mackerel, as well as other species like cod and bluefin tuna. The establishment of the Common Fisheries Policy by the European Union and the International Commission for the Conservation of Atlantic Tunas aimed to address these issues, but enforcement and effectiveness were limited in the early years.