Rays and sharks are part of the same family (chondrichthyes) and use their sense of smell to detect prey. Out here if we put any old fish frames over the side the rays are the first to find it. So smelly bait might be worth a go and not necessarily fresh.
mackerel fillet . ur bait presentation is important tho and also ur rig . a ray would not land on ur bait to eat if it was next to a gripper...be like sleeping on a bed of nails for mr and mrs ray...so the right rig would be beneficial .
ray baits can be very regional even within a 5 mile radius . find the best for the area you are fishing .also the type of ray you are targeting will make a difference. down here its not catching the ray but stopping the dogfish getting there first. so sometime its the bait the dogs like so much