What was different about the fish from the west side and east sides of the Atlantic Ocean?

Between Newfoundland and Ireland it is about 2,060 miles (3,320 km); farther south it widens to more than 3,000 miles (4,800 km) before narrowing again so that the distance from Cape São Roque, Brazil, to Cape Palmas, Liberia, is only some 1,770 miles (2,850 km).