There are no protected mustangs in canada.There are 40,000 protected mustangs in the united states but none here. The program I watched (canadian geographic) said they had not been tested, it might be out of date as i'm not sure when it was produced.
I also said the Sable Island ponies are heavily managed. As far as I know by natural causes and by shots which prevent mares going into heat. There is also a famous scientist who lives there and moniters them continually.