MACROBENTHIC FAUNA IN DEAD-END CANALS OF THE MARYLAND COASTAL BAYS, USA

Benthic macroinvertebrates are biological indicators of ecological conditions in aquatic habitats, often determined by species diversity measures. The community structure of benthic macroinvertebrate fauna can change over time in response to environmental factors, habitat structure as well as weather and climate variability. The composition and abundance of macrobenthic fauna were investigated at six stations in selected dead-end canals in Maryland Coastal Bays (MCBs). Benthic samples were collected in May and June 2017 with a Van Veen grab, and a total of 5,090 and 4,291 macroinvertebrates were recorded, respectively. Water temperature increased from an average of 16.78 C to 23.02 C and salinity decreased from an average of 30.98 to 29.28 PSU over the 2 month time span. Sediment organic matter content was comparable over the two months with ranges of 2.9-13.8% (May) and 2.7-11.9% (June). Among the dead-end canal sites, polychaetes were the most abundant group across sites and their percent contribution to the fauna was higher in May (84%) than in June (66%). Most sites were notably dominated by the pollution tolerant Streblospio benedicti and Capitella spp. The analyses of additional samples collected from August and December in these dead-end canal sites will enable us to assess seasonal variations in the relative abundance of these species in relation to changes in environmental factors at the sites.