These big predator fish can have a strong fishy flavor that improves when it's marinated for an hour or two. One batch of marinade is enough for two good-sized steaks or 1.5 pounds of cubed fish.
2 T Lemon Juice
1⁄4 c Extra-Virgin Olive Oil
1 t Salt
1 pn Fresh-ground Black Pepper
Combine all ingredients well. Put in a sealable bag or close-fitting container with fish and marinate in the refrigerator for an hour (cubes) to 1.5 or 2 hours for steaks. When the time is over, drain and dry the fish and discard the marinade.