There are two closely related fish that are called Spanish mackerel. One that lives in the Atlantic, and one that lives in the Pacific.
Both kinds have oily flesh.
Atlantic Spanish mackerel have the scientific name of “Scomberomorus maculatus.” They can be found on the North American side of the Atlantic, ranging from Cape Cod down to Yucatan peninsula.
They have a green back, with silvery sides and have yellowish spots on them, with vertical lines on the side.
They grow 20 to 30 inches (50 to 75 cm) long. When they are around 20 inches (50 cm), they will weigh about 2 pounds (900g.)
They live in schools, and with their sharp teeth easily feed on small fish and squid.
They migrate north in the spring, return south in the fall.
“Scomberomorus commerson” is the Spanish mackerel that lives in the Pacific.
They have bluish green backs, with silvery-grey sides with vertical lines on their sides.
They grow up to 6 1/2 feet (2 metres) long, and weigh up to 110 pounds (50 kg.) They reach sexual maturity at about 2 years old, when they will be about 30 inches (80 cm) long.
When young, they live in schools; when older, they go off on their own.
They range from Australia up to the Mediterranean Sea, and through the Indian ocean and the Pacific up to Japan.
They have passed into the Mediterranean via the Suez Canal.