To gut fish, first rinse thoroughly; then, using a sharp knife, slit belly from vent hole (at base of anal fin) to gills. Remove head from just behind pectoral fins. Remove innards and scoop out kidney line (brownish-red line along spine). Season cavity with salt and pepper. Fill each cavity with 3 lemon slices and fresh herb sprigs. Wrap in parchment paper and fold to seal. Heat grill to medium and place bundles on grate seam side up. Cook 20 minutes.