In a glass dish, combine orange juice, soy sauce, oil, lemon juice, parsley, garlic, oregano and pepper.
Add tuna steaks and turn to coat.
Cover and refrigerate for 30 minutes.
Remove tuna from marinade and discard remaining marinade. Bake tuna at 450°F for 4 to 6 minutes or grill tuna, covered, over medium-high heat for 2 to 3 minutes; flip and grill for an additional 2 to 3 minutes.
191 calories; 4 g fat; 0.5 g saturated fat; 52 mg cholesterol; 571 mg sodium; 3 g carbohydrate; 0 g fiber; 33 g protein