Dermal ulcerations and mortalities of estuarine fishes as indicators of environmental problems

Dermal ulcers appeared in young menhaden Brevoortia tyrannus in 1984. Field sampling showed dermal ulcers in this clupeid and in species of other families of fish from Delaware to Florida. Some mortalities were associated with the lesions. No definitive causative organism or process of lesion development was discovered and the disease was called Ulcer Disease Syndrome (UDS) by some investigators. Because various fungi were found in many of the sores, the disease was termed Ulcerative Mycosis (UM) by others. The epizootic waned around 1989–1990 as did political and scientific interest. Renewed attention, due to outbreaks of ulcers and mortalities of fish attributed to the toxic dinoflagellate Pfiesteria piscicida, revealed that UDS/UM had persisted in many East Coast estuaries. In North Carolina and Chesapeakeʹs Pocomoke River, fish have died and some humans seem to have been affected. River closures resulted. The extent and nature of dinoflagellate and/or fungal involvement in ulcer epizootics of menhaden is under investigation. Unfortunately, ulcerations in other fishes are being largely ignored. Regardless of the principal causative organisms or the detailed processes involved in ulcer initiation and development and associated (?) mortalities, adverse environmental factors seem to have been involved in both epizootics.