Yes, there is plenty on EUS {epizootic ulcerative syndrome - or "Red Spot"} but those ulcers are caused by a fungus (Aphanomyces) that is not a problem until the fish get stressed by sudden changes in temperature, salinity, or acidity (in the case of northern NSW flooding of acid sulphate soils}. Common on mullet and bream in NSW estuaries, and very nasty. The fish get stressed, the fungus blooms in minor abrasions, and bacteria move in too to form a horrible ulcer.
These surf mulloway with rashes/bruises are coming from pristine, remote, surf beaches. Hard to imagine better water quality