The decal antenna has been designed to withstand the elements with the electrodes made of marine grade stainless steel, and the connection between these of a robust flexible coated cable. Scratches on the electrodes, normal discolouring of the stainless steel (tea staining), or scratching the covering decal will not affect performance.
However it is possible it could be damaged through your board getting dinged on a reef etc. In this case you can remove your decal antenna and replace it with a new one. This needs to be replaced as a complete assembly, you cannot just change the decal antenna.
Please see the Ocean Guardian website "How to video's" to see how remove your tail pad and install a new decal antenna.