Atlantic mackerel is the small fish with the mild flavor and big, meaty texture of a large fish. But there are many other reasons to give it a try. Unlike large apex predators like tuna and swordfish, these mackerel are small, schooling fish that occur in great abundance, providing a truly sustainable harvest. They`re caught by hook and line, with little to no bycatch, by traditional fishing families in northern Spain. Since Atlantic mackerel are low on the ocean food chain, they don`t have the high levels of mercury and other toxins that can concentrate in larger fish. And they are an excellent source of protein, vitamin B-12, and other essential nutrients, with 500 mg of Omega 3 fatty acids per serving.