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| Maryland Coastal Bays - Overview:
Synopsis
Coastal Bays Health Index 59% C+ | Overall average grade for the Coastal Bays: C+
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2008 Coastal Bays health is moderate
The overall health of the Coastal Bays, assessed using six water quality and biotic indicators, was moderate in 2008, obtaining an overall grade of C+. As expected, the health of the six individual reporting regions varied, ranging from B (good) to D+ (poor). The highest ranked region was Sinepuxent Bay, while the lowest ranked region in 2008 was virtually tied between Newport Bay and St. Martin River.
Although the overall score for the Coastal Bays was a C+, there were distinct differences among reporting regions. For instance, western tributaries such as St. Martin River and Newport Bay had the lowest grades, whereas the northern regions had moderate grades. The southern regions, including Chincoteague Bay, had the highest grades.
Seagrass acreage up slightly
The abundance of underwater seagrasses in the Coastal Bays increased by 17% last year, from 9,319 acres in 2007 to 10,916 acres in 2008. While this increase is a good sign that the downward trend observed in recent years may have stopped, it is still one of the
lowest acreages seen in over a decade and only 57% of the peak acreage observed in 2001.
Clam density in Isle of Wight Bay reaches 15-year high
Hard clam survey data from 2008 showed that clam recruitment in 2006 was extremely successful such that small clams (31–50 mm) made up 30–40% of the populations in Assawoman and Isle of Wight Bay, respectively. This boosted the total clam population in Isle of Wight Bay to the highest seen in the 15-year monitoring program. Populations in the other bays have remained stable.
Water quality indicators ranged from poor to very good among regions
Scores of individual water quality indicators showed distinct separation among the reporting regions and ranked similar to the final health index grades. Accordingly, the two mainland tributaries of St. Martin River and Newport Bay ranked the lowest of all regions, suggesting that the aquatic health of the Coastal Bays is strongly affected by nutrient loading from upland areas. Despite the moderate to good health scores in the other regions and an increase in seagrass area—which is likely due in part to lower-than-average rainfall in 2008—recent increasing trends in nutrient concentrations indicate that development in the watershed poses a serious threat to the health of this ecosystem.
Health Index Map
This map shows the Coastal Bays Health Index for all reporting regions. You can also access individual reporting region summary pages by clicking on them, or mousing over for quick summaries.
Region Rankings
The overall score for the Coastal Bays was a C+ but there were distinct differences among reporting regions. For instance, St. Martin River and Newport Bay had the lowest grades, whereas the northwestern regions had moderate grades. The southwestern regions, including Chincoteague Bay, had the highest grades. Because St. Martin River and Newport Bay ranked the lowest of all regions, this suggests that the aquatic health of the Coastal Bays is strongly affected by nutrient loading from upland areas. Despite the moderate to good health scores in the other regions and an increase in the area of seagrasses—which is likely due in part to lower than average rainfall in 2008—recent increasing trends in nutrient concentrations indicate that development in the watershed poses a serious threat to the health of this ecosystem.
This table shows the indicators and the overall Coastal Bays Health Index for all reporting regions. Mouseover the index values to see the values of the component indicators/index. You can also access individual reporting region summary pages by clicking on their name, or indicator details by clicking on their icons.
| Sinepuxent Bay | Chincoteague Bay | Overall Coastal Bays | Isle of Wight Bay | Assawoman Bay | Newport Bay | St. Martin River | |||
 Chlorophyll a | 97 | 97 | 94 | 91 | 83 | 69 | 75 | ||
 Dissolved Oxygen | 97 | 86 | 80 | 47 | 50 | 54 | 45 | ||
 Total Nitrogen | 100 | 85 | 81 | 73 | 57 | 40 | 38 | ||
 Total Phosphorus | 66 | 44 | 47 | 49 | 60 | 45 | 46 | ||
 Seagrass | 61 | 38 | 37 | 31 | 32 | 14 | 3 | ||
 Hard Clams | 18 | 10 | 12 | 40 | 16 | 3 | 5 | ||
 Coastal Bays Health Index | 73 | 60 | 59 | 55 | 50 | 38 | 35 | ||
Excel SpreadsheetRegion Summaries
Listed in order of Coastal Bays Health Index from best to worst. You can access more detailed information on each reporting region by click on the region names.
| Region | Score (%) | Comments |
| Sinepuxent Bay | 73 B | Sinepuxent Bay received the highest grade of all reporting regions: B This reporting region had the highest grade of all the regions and separate indicators were top-ranked (i.e., 1st) except for the hard clams indicator that was ranked 2nd. |
| Chincoteague Bay | 60 B- | Chincoteague Bay received a B- grade. This reporting region had the second-highest grade of all the regions and separate indicators were generally ranked 2nd, except for hard clams and total phosphorus that were ranked 4th and 6th, respectively. |
| Overall Coastal Bays | 59 C+ | Overall average grade for the Coastal Bays: C+
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| Isle of Wight Bay | 55 C+ | Isle of Wight Bay received a grade of C+. The Isle of Wight received the third-highest grade of all the reporting regions in 2008. Of the water quality indicators, dissolved oxygen ranked lower than either chlorophyll-a or nutrients. Scores for both seagrasses and hard clams were poor. |
| Assawoman Bay | 50 C | Assawoman Bay received a grade of C. This region had moderate water quality related to dissolved oxygen and nutrients, yet had good chlorophyll-a. Hard clam and seagrasses were very poor to poor in this region, which resulted in a moderate score overall. This reporting region had the fourth-highest grade of all the regions and separate indicators were ranked from 2nd to 4th in 2008. |
| Newport Bay | 38 D+ | Newport Bay received a grade of D+. This reporting region had the second-lowest grade of all the regions, just slightly higher than St. Martin River, and all indicators were ranked 5th or 6th in 2008, except for DO that ranked 3rd. |
| St. Martin River | 35 D+ | St. Martin River received a D+ grade. The worst score of any reporting region in 2008 was a result of moderate to very poor grades for every indicator measured except chlorophyll-a, that was good. This region had lower grades than any other region for dissolved oxygen, total nitrogen and SAV. |
Comparison
Comparison of Coastal Bays Health Index scores for 2008 (
) compared to (
)| Score (%) | |
| Sinepuxent Bay | |
| Chincoteague Bay | |
| Overall Coastal Bays | |
| Isle of Wight Bay | |
| Assawoman Bay | |
| Newport Bay | |
| St. Martin River |
Background
These resources provide detailed background information on the ecology and health of the coastal bays.
Shifting Sands: Environmental and cultural change in Maryland's Coastal Bays
William C. Dennison, Jane E. Thomas, Carol J. Cain, Tim J.B. Carruthers, Matthew R. Hall, Roman, V. Jesien, Catherine E. Wazniak, and David E. Wilson
Referring to both the dynamic nature of the barrier islands forming the coastal lagoons of Maryland’s Atlantic Ocean coastline and also the changing cultural landscape, Shifting Sands is a richly illustrated, multi-authored introduction to Assawoman Bay, Isle of Wight Bay, St. Martin River, Sinepuxent Bay, Newport Bay, and Chincoteague Bay. This book leads the reader on a voyage of discovery, providing a user-friendly guide to the history, setting, context, and ecology of these waterways nestled behind Assateague, Fenwick, and Chincoteague Islands. Photographs, conceptual diagrams, maps, and graphs are used to showcase the key features of and major threats to these magnificent bays, watersheds, and islands, with recommendations for how to preserve them for future generations.
State of the Maryland Coastal Bays 2004 (Report)
Wazniak, C., M. Hall, C. Cain, D. Wilson, R. Jesien, J. Thomas, T. Carruthers, and W. Dennison
This report summarizes monitoring data collected over the past several years for water quality, aquatic living resources, and habitat categories. It utilizes conceptual diagrams for each reporting region to highlight the key ecosystem processes, biota and estuarine health problems.
Maryland Coastal Bays Ecosystem Health Assessment 2004
Maryland’s Coastal Bays, the shallow lagoons nestled behind Ocean City and Assateague Island, comprise a complex ecosystem. These estuarine bays, at the interface between fresh and saltwater, provide habitat for a wide range of aquatic life. But like many coastal systems, they face threats from intense development, nutrients, sediments, and other stresses associated with human activities. This report documents the most up-to-date status of water quality and living resources in the Coastal Bays and highlights management steps being taken to reserve them.