MA3 Aquatic Ecotoxicology
254 Portland Ballroom
8:00 AM - 12:00 PM, Monday
() Altered stress responses in Pacific herring subchronically exposed to an oil-water dispersion.
Kennedy, C1, Farrell, A1, 1 Simon Fraser University, Burnaby, BC, Canada
ABSTRACT- The organismal stress response was examined in juvenile Pacific herring, Clupea harengus pallasi, sub-chronically exposed to pulses of three concentrations of an oil-water dispersion (OWD) of North Slope crude oil over a 9 week period. Total PAH (TPAH) concentrations at the beginning of each new pulse were: low (L) 18.3±9.2 medium (M) 47.5±19.3 and high (H) 132±12.6 ppb TPAH. TPAH concentrations declined with time and the composition of the OWD shifted toward larger and more substituted PAHs with time. Significant elevations in plasma cortisol (mean ± SE peak concentrations: C: 24.2±2.4, H: 108.7±8.8 ng/ml), lactate (C: 37.4±3.8, H: 88.7±5.1 mg/dL), and glucose ( C: 142.8±6.5, H: 216.6±6.6 mg/dL) occurred in fish exposed to the first pulse of OWD at the highest TPAH concentration, all of which returned to baseline levels by 96 h. Subsequent pulses first resulted in muted (51% reduction) cortisol elevations, followed by an abolishment of the stress response with further exposure. A similar trend was found for both plasma lactate and glucose concentrations. In contrast, plasma Cl-, Na+ and K+ concentrations in OWD-exposed fish were consistently higher than those in control fish at post-72 h of exposure, which were not correlated with the OWD-induced stress response. These results suggest that herring exposed subchronically to OWD may not be able to successfully mount a stress response which could limit their ability to physiologically cope with dynamic environments.
Key words: herring, oil, stress, cortisol