TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Ulcerative Dermatopathies Of Striped Bass (Morone saxatilis) In The Maryland Portion Of The Chesapeake Bay Watershed E.B. May Maryland Department of Natural Resources, Oxford, MD. Ulcerative dermatitis in Chesapeake Bay striped bass first was reported to the Maryland Department of Natural Resources (DNR) in September 1994 by a pound netter in the Potomac River. At least 30% of the striped bass by-catch was affected. In September and October 1994 additional reports were received from pound netters working in Tangier Sound, and near Hoopers and Tilghman Islands. By late September of 1994 reports of fish with skin abnormalities were being received by DNR from anglers as far north as Pooles Island and throughout southern Chesapeake Bay. From the descriptions of the fish taken the sores were similar to those described during the original incident. Specific percentages of fish affected by the condition could not be calculated based on angler reports, however pound net haul percentages ranged from 20-40%. In subsequent years (1995, 1996 and 1997), similar skin abnormalities in striped bass have been reported by pound netters and anglers. A report by Baya et al. (1997) implicated Edwardsiella tarda (a gram negative rod-shaped bacterium common to the guts of many fish, and pathogenic to cultured channel catfish) as the causative agent. This pathogen had never been linked to diseases in wild fish; the report by Baya et al. (1997) was the first to mention E. tarda affecting wild populations. In October 1997, Mr. John Coll of the Northeast Fishery Center examined striped bass from surveys being conducted by the Fisheries Service, and found similar bacteria as well as Pseudomonas fluorescens, Pseudomonas dimunita, Shigella sp., Bacillus sp., Actinetobacter sp., Moraxella sp., Peptococcus sp., and Pasturella haemomolytica. Surveys by MD DNR during 1997 found an overall incidence rate of 12% in striped bass taken from pound and gill nets, however, in young-of-the-year no lesions were reported. This presentation will review the current information and provide descriptions of the anatomical findings both gross and histological. Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page