1. Caged Crassostrea ariakensis Deployment in Chesapeake Bay: Growth, Disease and Mortality Kennedy T. Paynter, Jacob Goodwin, Marcy Chen University of Maryland, College Park Donald Meritt University of Maryland Center of Environmental Science Stan Allen Virginia Institute of Marine Science

2. Previous Observations Calvo et al., –C. ariakensis grew much faster than C. virginica –C.a. experienced much lower mortality due to disease Grabowski et al., –C.a. grew faster than C.v. in intermediate to high salinities but did not grow well in low salinities. However both studies, Compared diploid C.v. to triploid C.a. Did not compare specific parasite free (SPF) C.a. to SPF C.v.

3. Experimental Design Md sites - Severn, Patuxent, Choptank Rivers Va site - York River Deployed April 2004 1300 individuals of each species - –Both triploid –400 in each of two ADPI bags - sample –250 in each of ADPI “reef” trays - left alone Monitored monthly since deployment Size, mortality, P. marinus prevalence

4. Site Locations Severn River Patuxent River Choptank River York River

5. 6 psu

6. 9 psu

7. 11 psu

8. 17 psu

10. C. ariakensis C. virginica Approximately 200 of each species

11. Perkinsus marinus In addition to growth, the difference in disease susceptibility between native and non-native oysters is important in considering an introduction

15. Mortality since deployment LOCATIONC. ariakensisC. virginica Severn 26 20 Choptank 36 45 Patuxent 24 6 York 11 21 Mean 24 23

16. Summary C. ariakensis grew much faster in higher salinities but only slightly faster in lower salinity waters in Maryland. C. ariakensis acquired lower dermo prevalence. Mortality in both species was low and similar, however, dermo infections remained light during this portion of the study and heavy disease-related mortalities appear likely in C.v. in the near future.

17. York River Spat Settlement in 2004 0.4 spat/oyster 2.3 spat/oyster C. virginica C. ariakensis Spat settlement on C. virginica (A) and C. ariakensis (B). Spat were found in significantly higher numbers in C. ariakensis (ANOVA; P<0.02). A. B.

18. Additional Observations There were differences in Polydora sp. infestations (See poster A6. Ward) Hypoxia tolerance varied between C. ariakensis and C. virginica (See poster A4. Harlan)

19. Acknowledgements Funding from Maryland Sea Grant, NOAA, and Maryland Department of Natural Resources. Technical assistance from, Mark Sherman Steve Allen,, Tim Koles, Nancy Ward, Terra Lederhouse, Nicole Harlan, Paul Miller, Kennedy and Rick Paynter.

20. Spat Settlement York River was the only site with spatfall in 2004 Spat were found in significantly higher numbers in C. ariakensis (ANOVA: P<0.02)

21. Mortality Table Comparisons Location C. Ariakensis C. virginica Severn 74 80 Choptank 64 55 Patuxent 76 94 York 89 79 Avg. 76 77