Meeting Abstract
The Eastern oyster, Crassostrea virginica, co-occurs with the invasive tunicate, Styela plicata, and the latter species is particularly prevalent in oyster hatcheries, where it is a potential competitor of oysters for food and space. We evaluated the role of air exposure on oxidative damage in both species to help understand environmental tolerances. 70 individual tunicates and 70 individual oysters were collected from the docks of UNCW’s Center for Marine Science. Tunicates were of various sizes (ranging from 19-80 mm) while oysters were of similar sizes (ranging from 28-57 mm, ages 6 to 9 months). 10 individuals from each species were randomly placed in one of the following 7 groups: control (continuous water immersion), 6, 12, or 24-h air exposure, or 6, 12, or 24-h air exposure followed by 6 h of water immersion. Tissues from both organisms were examined for oxidative damage using immunoblotting procedures for ubiquitin (protein degradation), protein carbonylation (protein oxidative damage), and 4-HNE (lipid oxidative damage). Tunicates had greater increases in oxidative damage markers than oysters, suggesting that air exposure may lead to increased physiological stress in this species. There was also evidence of a negative correlation between tunicate length and each marker of oxidative damage, suggesting that size of the individual plays a role in the extent of the stress induced by air exposure. This interaction could mean that frequent air exposures will prevent larval and juvenile S. plicata recruitment. This research has implications for the use of air exposure as a method to reduce invasive tunicate densities on oyster cages without significantly dampening oyster growth and viability.
