Mackerel. Wild Both dark-fleshed Atlantic mackerel and its light-fleshed cousin, Spanish mackerel (also harvested in U S waters, despite its name), are fish lovers’ fishes. Bristling with lush oceanic savonness, they have a delectable combination of star quality flavor and meltingly tender texture thanks to their abundant fish oils. Atlantic mackerel is more assertive, prized by Japanese sushi chefs for its distinctive personality. Spanish mackerel’s milder flavor makes it a good “introductory mackerel” for uninitiated tasters of this abundant species.