Meeting Abstract
The invasive zebra mussel (Dreissena polymorpha) has caused significant ecological and economical damage since its introduction to the United States. While zebra mussel physiology has been examined for a variety of environmental conditions, less is known about the cellular processes during stressful fluctuations. Also, given the variability in reported values for both optimal and lethal temperatures, it is challenging to develop biologically relevant laboratory experiments for a specific population. Therefore, our objectives were to (1) determine the optimal conditions for a zebra mussel population at Banner Marsh by measuring survival, growth, and cellular physiology (via cellular stress markers) to environmental parameters (water quality, food quantity, and temperature), and (2) investigate whether clumping behavior altered mussel performance. Field enclosures were deployed for four weeks in May and mid-June 2018. Mussels were either allowed to clump freely as they do in nature or divided into individual chambers. While water quality and food quantity varied over time, conditions remained within the optimal ranges. Mussel survival was consistently high for both treatments and months. On average, mussels experienced greater shell growth and lower tissue loss when they were housed individually, suggesting that clumping negatively affects growth. Yet, clumping behavior did not produce significant differences in the levels of cellular markers. Mussels experienced greater shell growth and lower tissue loss in May than in June, which may be attributed to the fact that water temperature regularly exceeded 31°C in June/July. These results were corroborated by significantly higher heat-shock protein 70 levels in June/July.
