Date Awarded

1994

Document Type

Thesis

Degree Name

Master of Arts (M.A.)

Department

Virginia Institute of Marine Science

Abstract

Secretion of mucus by epidermal goblet cells is an important first line of defense for teleosts. It protects them against many of the biological, physical and chemical insults they encounter in their environment. This project monitored changes in hemoglobin concentration in epidermal mucus and in the density, diameter and mucus quality of epidermal goblet cells in the mummichog, Fundulus heteroclitus, following exposure to creosote-contaminated sediment. Male fish (200) were exposed for 13 days in flowthough aquaria to either an uncontaminated reference sediment or contaminated sediment containing 30% Elizabeth River sediment. Fish were sampled on Days 0, 3, 7 and 13. The hemoglobin content of their mucus was assessed using a commercial hemoglobin test strip. Their condition index was determined and a portion of their ventral skin was mounted after sequential staining by alcian blue and periodic acid Schiff s reagent. The proportion of the mucin types present in the goblet cells, differentiated by the stains, was determined using light microscopy (600x). The aromatic compound concentrations in test aquaria effluents decreased significantly during the experiment, probably as a result of a reduction in resuspension of the sediment by the fish. The condition index was lower and the mortality rate and occurrence of epidermal lesions were higher in the treated fish than in the control fish. The hemoglobin content in the epidermal mucus of treated fish was significantly higher than in control fish. Significant reductions in both size and density of goblet cells observed in treated fish suggested a mucus secretion rate exceeding its production rate. Significant variations in mucin types occurred in both treatments, most likely as a result of the transfer of the fish from the holding tank to the experimental aquaria. Significant changes in mucin types between treatments did not occur until Day 13 and are not believed to be directly related to the creosote present in the treatment sediment.

DOI

https://dx.doi.org/doi:10.25773/v5-vvc6-1809

Rights

© The Author

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