Stream Living Resources

Conditions of animal communities indicate most streams are degraded.  However, conditions are showing improvement.

To report overall stream health, Maryland DNR researchers used the diversity of freshwater fish and benthic organisms as indicators. Samples were collected by DNR field crews and Stream Waders volunteers in 2001. In the Coastal Bays watershed, this "Index of Biotic Integrity" (IBI) was calculated for all sites with adequate data. These IBIs rated stream health according to the species of fish or invertebrates found there.

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Most fish and benthic (bottom-dwelling) species found in the Coastal Bays watershed streams were classified as pollution-tolerant. 2001 stream benthic index results from 59 sites rated most as either poor (15%) or very poor (75%), while the remaining sites rated fair (10%). Stream freshwater fish index results from 12 sites rated most as poor (14%) to very poor (43%), with 43% rated as fair. Impacts to the biota of Coastal Bays streams are likely the result of physical habitat modifications (e.g., ditching). Ditched streams generally have less habitat diversity and lower flows than minimally-altered streams that retain natural wetland characteristics.


The benthic community indicated general improvements between 1975 and 2003 in water quality at 5 stations on St. Martin River and Trappe Creek.

Benthic trends show improvement in water quality

The benthic community indicated a strong improvement in water quality from the very poor to lower fair range at two long-term stations on the St.Martin River.  Both sites showed an improvement in number of species, biotic and diversity indices. However, the benthic community indicated no significant trend in the fair water quality at Birch Branch.

Benthic communities at both Bottle Branch and Trappe Creek stations showed a slight improvement in water quality from the poor to lower fair range over the years sampled. Both stations showed an increase in numbers of species, and Bottle Branch also showed an improvement in biotic index values.

Coastal Bays Stream Reports

Find out more information about the MBSS and the Stream Waders Program!


If you have any questions about Maryland's Coastal Bays, 
please feel free to e-mail, Cathy Wazniak, or call (410) 260-8638.

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