Subscribe
| Browse History: Chlorophyll a (2009) | Coastal Bays Health Index (2009) | Dissolved Oxygen (2009) | Hard clams (2009)
Hard clamsHard clams are a benthic organism that requires good water quality conditions to survive. Clam densities relatively close to or above the threshold indicate that the water quality and physical conditions are suitable for clam growth and reproduction.
Maryland Coastal Bays - Indicator Details:
Threshold Map
You need to upgrade your Flash Player
Editable Vector Version (SVG)
High Resolution Raster Version (JPG)
Station Data Download (Excel)
This map shows how the average hard clam density for each reporting region compared to the threshold (as a percentage). No region exceeded 40% of the threshold in 2009. In 2009, hard clam densities were commonly low compared to the threshold level in all regions. While the reason for the poor to very poor conditions for hard clams in the Coastal Bays is yet to be determined, it is likely the result of water quality conditions that are not favorable to hard clam survival.
Creating this map
Hard clam densities were measured at approximately 204 stations in 2009. Average hard clam density is represented at each station.
Hard clam densities were measured at approximately 204 stations in 2009. Average hard clam density is represented at each station.
Ranking
Comparison of Bay Health Index scores for 2009 (
) compared to (
)| Score (%) | |
| 0 20 40 60 80 100 |
| Isle of Wight Bay | |
| Sinepuxent Bay | |
| Assawoman Bay | |
| Overall Coastal Bays | |
| Chincoteague Bay | |
| Newport Bay | |
| St. Martin River |
This figure ranks each region from best to worst forhard clams. The hard clam indicator was poor to very poor for almost all regions of the Coastal Bays 2009. While the reason for the poor to very poor conditions for hard clams in the Coastal Bays is yet to be determined, it is likely the result of water quality conditions that do not favor hard clam survival. The Isle of Wight Bay region had the highest hard clam score in 2009 compared to any other reporting region, while the score of Newport Bay was virtually zero.
(Hard clam data were not available for St. Martin River in 2009.)
Excel SpreadsheetThreshold Levels
| Region | Threshold (clams m-2) |
| Assawoman Bay | 1.00 |
| Isle of Wight Bay | 1.19 |
| Sinepuxent Bay | 1.04 |
| Newport Bay | 0.51 |
| Chincoteague Bay | 1.34 |