Growth responses of an estuarine fish exposed to mixed trace elements in sediments over a full life cycle

Hatchling Cyprinodon variegatus were raised in the presence or absence of sediments contaminated with mixed trace elements to examine lethal and sublethal bioenergetic effects (metabolic rate, lipid storage, growth, reproduction) over a full life cycle (>1 year). Contaminated sediments were derived from a site receiving coal combustion residues (CCR) and were elevated in numerous trace elements including Al, As, Ba, Cd, Cu, Se, and V. Exposures were conducted at two levels of salinity (5 and 36 ppt) to examine the potential interaction of this variable with contaminants. Salinity had no effect on responses measured. Over the course of the study, fish exposed to contaminated sediment accumulated several CCR-related trace elements, including As, Cd, Se, and V. There were no differences in fish survival for contaminated sediment treatments and uncontaminated sediment treatments, nor were there differences in metabolic expenditures. However, growth, male condition factor, and storage lipid content in females were reduced due to contaminant exposure. No significant effects on fecundity or the proportion of females that were gravid at the end of the study were observed, yet females raised under control conditions produced 12% larger eggs than did females raised on contaminated sediments. During the presumably most-sensitive early life stages, individuals were not noticeably affected by contaminants, but rather the effects of exposure became apparent later in life. Because many species inhabit contaminated areas for long periods of time, often encompassing the entire life cycle, exposures focused only on specific life stages may substantially underestimate the overall responses elicited by individuals.