There are a total of 15 Destructible Objects located on Miagani Island and they can be found in the following locations:
Breakable Object 01
Map Co-ordinates: 2725, 2793
On a bridge support on the eastern side of Mercy Bridge.
Breakable Object 02
Map Co-ordinates: 2961, 2932
Near the large neon dolphin signs on the side of the building located at the coordinates listed.
Breakable Object 03
Map Co-ordinates: 2993, 2730
High up on the westernmost tower atop the ‘Bank of Gotham’ building.
Breakable Object 04
Map Co-ordinates: 3130, 2797
This shield is located on a wall above the entrance to a tunnel along the main road.
Breakable Object 05
Map Co-ordinates: 3248, 2922
Above the entrance to a tunnel at the co-ordinates listed.
Breakable Object 06
Map Co-ordinates: 3327, 2814
This militia shield is mounted on the south-facing side of the building directly east of Grand Avenue Station.
Breakable Object 07
Map Co-ordinates: 3598, 2673
This one is found on the western side of the Wayne Building area, on the walls near the water. You’ll need to jump the Batmobile across the water to this position via the jump at the northwest corner of the compound.
Breakable Object 08
Map Co-ordinates: 2992, 2574
If you drive to the top of the parking garage, you’ll see this on the building opposite as you reach the rooftop.
Breakable Object 09
Map Co-ordinates: 2844, 2588
On the side of a building above the ‘Koul Brau’ sign and opposite from the ‘Gotham Tailor’ shop.
Breakable Object 10
Map Co-ordinates: 2878, 2368
This one is found on the side of a building, beneath an overhead walkway linking it to another building. It is located just above the top of the stairs with the horse statues at the bottom.
Breakable Object 11
Map Co-ordinates: 3021, 2022
Near the top of the building on the east-facing side at the co-ordinates listed.
Breakable Object 12
Map Co-ordinates: 3203, 1850
This shield can be found on the wall on the eastern side of the Pinkney Orphanage building.
Breakable Object 13
Map Co-ordinates: 3449, 2168
On the western side of the Newton Fairgrounds building (in front of the Ferris Wheel). You can shoot the shield from across the water to the northwest.
Breakable Object 14
Map Co-ordinates: 3339, 2358
This militia shield is on the northern side of the ‘Gotham Tonight’ building.
Breakable Object 15
Map Co-ordinates: 3412, 2430
This one is on a stone pillar directly opposite the entrance to the ‘Gotham Tonight’ building.