The effect of petroleum hydrocarbons on a freshwater environment, the Spring Gulch Wetlands, Canadian Forces Base Goose Bay, Labrador using pearl dace (Margariscus (Semotilus) margarita) as an environmental indicator

Mercer, I. R. Geoffrey (2001) The effect of petroleum hydrocarbons on a freshwater environment, the Spring Gulch Wetlands, Canadian Forces Base Goose Bay, Labrador using pearl dace (Margariscus (Semotilus) margarita) as an environmental indicator. Masters thesis, Memorial University of Newfoundland.

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Abstract

A study was conducted to determine the impact of petroleum hydrocarbons on pearl dace, Margariscus (=Semotilus) margarita, inhabiting stillwaters (SW) 1-4 of the Spring Gulch Wetlands, Canadian Forces Base Goose Bay, Labrador. The results often (10) biomarkers were compared to results for pearl dace captured from three reference sites (R1-3) at varying distances from CFB Goose Bay. -- Evidence supporting the premise that the extinction of pearl dace from the Spring Gulch Wetlands as a consequence of the chronic effects of petroleum hydrocarbon contamination was collected. The petroleum hydrocarbon contaminant levels in SW1, 3 and 4 impaired reproduction in pearl dace populations. There was a predominance of female fish in SW1, 3 and 4 and they were producing mature eggs in 1995 but none had spawned. There were none, or very few, juvenile fish in SW1, 3 and 4, suggesting reproductive failure and/or low reproductive survival rates. Fish collected from SW1, 3 and 4 were also longer, heavier and had higher condition factors than fish sampled from three reference sites (R1-3). There were more, and greater degrees, of histopathological lesions in fish sampled from SW1,3 and 4 compared to the reference sites. These lesions included interlamellar hyperplasia, hepatic lipid vacuolation, pigmented and non-pigmented splenic melanomacrophage aggregates and significant splenic concentrations of hemosiderin. Mixed function oxygenase activity (7-EROD) was elevated only in samples of liver taken from pearl dace from SW4 in 1996 but not in 1995. It is possible that estrogenic hormonal levels disrupted 7-EROD induction in 1995. -- The absence of juvenile fish, high prevalence of histopathological lesions, delay in seasonal maturity, and the complete disappearance of pearl dace from SW1, 2 and 3 over the two-year study period suggests that the pearl dace population at SW4 also faces eventual extinction.

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