Preheat Grill: Preheat your grill to medium-high heat (about 400°F). Clean and oil the grill grates to prevent sticking.
Prepare Marinade: In a small bowl, mix olive oil, lemon zest, lemon juice, minced garlic, thyme, rosemary, salt, and pepper.
Marinate Fish: Coat the striped bass fillets with the marinade. Allow them to marinate for at least 15-30 minutes.
Grill Fish: Place the fillets on the preheated grill, skin-side down (if skin is on). Grill for 3-4 minutes on each side, or until the fish reaches an internal temperature of 145°F and easily flakes with a fork.