Date of Award

Spring 1986

Document Type


Degree Name

Master of Science (MS)


Biological Sciences



Committee Director

Ray S. Birdsong

Committee Member

Raymond W. Alden, III

Committee Member

James F. Matta

Committee Member

Fred Singleton

Call Number for Print

Special Collections LD4331.O35O78


Fishes from the industrialized environs of the Elizabeth River, Virginia were surveyed for external evidence of disease during June through October 1984. A highly significant (p < 0.001) incidence of disease was found in demersal fishes collected by otter trawl from a site in the industrially contaminated Southern Branch compared to a less contaminated Western Branch site. Cataracts, fin erosion and dermal lesions were the most commonly occurring anomalies in the Southern Branch finfish.

Static, solid-phase toxicity tests employing sediment collected from the Southern Branch site resulted in an immediate toxic stress in the spot, Leiostomus xanthurus, which resulted in 100% mortality within 24 hours, compared with no mortalities in control systems. Spot exposed to control, i.e., pollution free, and diluted Southern Branch sediments innoculated with the pathogenic bacterial species, Vibrio anguillarium, developed significant (p 0.020) cases of fin erosion at a mean total bacterial community density of ≥ 2.4 x 107 cells/ml. No significant cases of fin erosion were produced in fishes exposed to control and diluted Southern Branch sediments without V. anguillarium. A significantly higher (p = 0.05) total bacterial density developed in the diluted Southern Branch sediments compared with the control sediment.

It is hypothesized that the industrially contaminated Southern Branch sediment favors development of populations of bacteria such as V. anguillarium which are pathogenic to fishes inhabiting this system. Furthermore, an increase in the incidence of disease in fishes from the Southern Branch may be the result of large populations of pathogenic bacteria and industrial pollution stress.


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