Meeting Abstract
In resource limited environments fish compete and establish social hierarchies in which one fish is dominant and the other subordinate. Dominant fish are more successful at monopolizing resources and generally have higher fitness and survival, while subordinate fish suffer not only the loss of resources but also a cascade of negative physiological impacts as a result of chronic stress. Predictors for dominance vary between species but typically combine aspects of personality with physiological traits such as size difference, metabolic rate, and variation in circulating hormone levels. Interestingly, work in the Gulf of Mexico following the Deepwater Horizon oil spill has shown that exposure to low concentration of PAHs found in crude oil impairs several aspects of physiological performance, including aerobic scope and swim performance. This leads to hypothesis that individuals exposed to sub-lethal oil concentrations may be predisposed to subordination. We sought to explore this hypothesis using the economically important red drum, which is native to many of the habitats impacted by the Deepwater Horizon oil spill. Initial experiments validated the underlying mechanisms of hierarchy formation using a dyad competition test design, which demonstrated that dominant individuals had significantly higher aerobic scope than matched subordinates. Furthermore, exposure to environmentally realistic oil concentrations resulted in subordination. These data demonstrate that sub-lethal oil exposure can impact social status in red drum, which can result in a number of downstream ecological physiological consequences.
