Oyster Reef Restoration in the Chesapeake Bay Kelly Galyean Department of Biological Sciences, York College of Pennsylvania Introduction Oyster reefs in the Chesapeake Bay are in great danger. Overfishing, habitat degradation, an increase in nutrients, and a decrease in water quality are causing a downward spiral of the overall quality of the Chesapeake Bay (Lenihan 1999). It is believed that oysters were once able to filter the entire bay in one day; today the oyster population is so low that it would take the oysters an entire year to filter the bay (Newell 1988). There is a great attempt to restore the Bay to what it was 100 years ago. Improvements are being made to decrease the pollution entering the bay and the next step is bringing back the oysters. Oysters would be able to filter out nutrients, making the water clearer and healthier so that seagrass populations could grow and provide another underwater habitat in the bay (Peterson et al. 1999). Studies have been done to show that man-made oyster reefs have the ability to successfully function as natural reefs (Meyer et al. 2000). In the Chesapeake Bay, there has been a lot of time and money spent on oyster restoration with little success (Lenihan 1999). Understanding how oyster reefs function as a community will aid in a better understanding of how they can be successfully restored. The purpose of this study is to investigate the feeding and biodeposition rates and of American oysters (Crassostrea virginica), ghost anemones (Diadumene luecolena), and Atlantic ribbed mussels (Geukensia demissa) under difference flow regimes. With this study, we hope to gain a better understanding of what is needed to create successful man-made oyster reef. Completed Research H o : There is no difference in feeding and biodeposition rates between anemones, oysters, and mussels. Proposed Research H o : There is no difference in feeding and biodeposition rates of anemones, oysters, and mussels with increased flow. Materials and Methods – Completed 10 American oysters (Crassostrea virginica) 10 Ghost anemones (Diadumene leucolena) 10 Atlantic ribbed mussels (Geukensia demissa)  Fed ~74600 cells using 1mL phytoplex.  Fluorescence used to measure amount of phytoplankton consumed in 2 hr.  Organisms placed in clean salt water for 48 hours to biodeposit.  Biodeposition was collected using suction filtration.  Biodeposition was dried for 48 hours in an oven at 37ºC and weighed.  Dry weight of organisms was measured excluding shell.  Statistical Analysis – One way ANOVA Literature Cited Chesapeake Bay Living Resources. Available from: Accessed 2004 December 15. Dame, R. and Libes, S Oyster reefs and nutrient retention in tidal creeks. Journal of Experimental Marine Biology and Ecology. 244:1-28. Dame, R.R., Spurrier, J.D., and Zingmark, R.G In situ metabolism of an oyster reef. Journal of Experimental Marine Biology and Ecology. 164: Lenihan, H.S Physical-Biological Coupling on Oyster Reefs: How Habitat Structure Influences Individual Performance. Ecological Monographs. 69: Nelson, K.A., Leonard, L.A., Posey, M.H., Alphin, T.D, and Mallin, M.A Using transplanted oyster (Crassostrea virginica) beds to improve water quality in small tidal creeks: a pilot study. Journal of Experimental Marine Biology and Ecology. 298: Newell, Roger I.E Ecological Changes in the Chesapeake Bay: Are they the result of overhavesting the American Oyster, Crassostrea virginica? Understanding the Estuary Advances in Chesapeake Bay Research Proceeding of a Conference Figure 1. There was no significant difference between the feeding rates of mussels, oysters, and anemones Figure 2. Oyster biodeposition was significantly greater than mussel biodeposition but not significantly different than anemone biodeposition. Anemone biodeposition was not signifcantly different than mussel biodeposition. Figure 5. Hypothetical graph showing the relationship between feeding rates with flow of passive filter feeders (anemones) versus an active filter feeders (oysters and mussels). Figure 4. Diagram of flow tank. A – Pump flow control. B – Organism holding screen. C – Fluorescence measurement zone. Discussion Oysters and mussels are active filter feeders, meaning they have the ability to create a current, while anemones are passive filter feeders and require flow to collect food. In the first part of this study there was no significant difference in consumption rate when there was no flow (Figure 1). In theory, the mussels and oysters should have consumed more than the anemones since there was no flow. This experiment should be repeated using a larger sample size and may provide more accurate results. The oysters had the largest amount of biodeposition with respect to the organism’s dry weight (Figure 2). The anemone produced an amount which was not significantly different from the oysters or the mussels. The mussels’ biodeposition was significantly less than the oysters which suggests the mussels use their food for growth, or it may take longer to produce waste than the oysters. Repeating this experiment with a larger sample size and over a longer period of time should show a greater difference between each species consumption and biodeposition. Including flow to the experiment would add another aspect to this study which would better simulate an oyster reef in the bay or its tributaries. The flow tank, diagramed in Figure 4, would provide the anemones the potential to consume food at a higher rate since more food would be carried by the water flowing past the organism. In this case, as flow increases so does the feeding rate for each organism. The anemones’ feeding rate will match that of the mussels and oysters’ more closely (Figure 5). The hypothetical biodeposition graph in figure 6 was based on the data collected from Figure 2. We expect that because the anemones will be consuming more, their biodeposition will become more similar to the biodeposition of the oysters. Because we are adding more time to the experiment, we will find if mussels use the food for growth or if they will take longer to deposit. Conclusion -All organisms must be taken into consideration while starting an oyster reef. In previous studies, mussels and anemones have been ignored, while all organisms must be taken into account during the first three years of an oyster reef’s development. They all work together to create a healthy living environment. -Starting an oyster reef where flow is high is predicted to increase the feeding and biodeposion, making the bay clearer and healthier. -The cleaner, clearer water will allow for more seagrass to grow and provide a higher level of oxygen to other organisms in the bay. Acknowledgments Jessica Nolan, PhD, YCP Mentor Chesapeake Bay Biological Laboratory Results - Completed Results - Proposed Figure 3. Diagrams of artificial oyster reefs. A - Tall oyster reef, with flow speed increasing with height. B – Short reef with a slower flow rate. Materials and Methods – Proposed Flow increases as reef height increases (Figure 3). Measuring consumption and biodeposition in a laboratory setting requires a flow tank (Figure 4). 90 American oysters (Crassostrea virginica) 90 Ghost anemones (Diadumene leucolena) 90 Atlantic ribbed mussels (Geukensia demissa)  Each species will be measured separately: 3 replicates of 30  Fed ~74600 cells using 1mL phytoplex  Fluorescence measure amount of phytoplankton consumed after 48 hours of feeding  Organisms placed in clean salt water for 72 hours after feeding to measure biodeposition  Biodeposition will be collected using suction filtration. Dried for 48 hours in an oven at 37ºC and weighed  The organisms will each be dried and weighed excluding shell to find the dry weight for each organism to be used for comparison.  Statistical Analysis – One way ANOVA Figure 6. Hypothetical Biodepositionrate rates showing the effect of increasing flow on biodeposition of each organism.