Meeting Abstract
As a vital component of many coastal marine ecosystems worldwide, seagrass beds serve as a habitat, food source, and nursery for many species and provide a buffer against the erosive nature of waves and currents. In temperate North America and Europe the main seagrass is eelgrass, Zostera marina. In the past a protist pathogen, Labyrinthula zosterae, has at times devastated eelgrass beds by causing eelgrass wasting disease. Although wasting disease has not recently spread epidemically in the eelgrass beds in Washington State, L. zosterae is commonly present at low concentrations. Understanding the mechanism by which it spreads is important for understanding the potential for future outbreaks. The large green eelgrass isopod Pentidotea resecata lives within and feeds upon eelgrass blades. It is an accomplished swimmer and frequently moves from blade to blade, and so could potentially serve as a vector for spreading the disease. In this study we examined the correlation in the laboratory between isopod bite marks and the location of new wasting disease lesions on eelgrass blades collected from Padilla Bay, WA. New L. zosterae lesions were significantly more likely to occur on blades that had bite marks than on those which had not been fed on. Additionally, on blades with both bite marks and lesions, the lesions appeared significantly closer to the bite marks than would be expected from a random distribution. These results imply that the feeding and movement of P. resecata between eelgrass blades may enhance the spread of the disease.
