The Choptank River complex provides food and critical habitat for many Chesapeake Bay species and was designated by NOAA as a Habitat Focus Area (HFA) in 2014. Over the period 2015-2017, we analyzed the impacts of land use on the condition of the aquatic ecosystem in the Tred Avon River, an important tributary of the Choptank River. The Tred Avon River is a good example of a watershed where multiple types of land use are competing for space and where urbanization is slowly replacing farm fields and forests. It is a watershed which is representative of different land uses, with relatively high development at the headwaters near Easton and at the mouth near Oxford as well as agriculture and undeveloped land along the remaining shorelines. The condition of eight different tributaries of the Tred Avon River representing different land uses were assessed using a suite of indicators including water quality, benthic habitat condition, benthic community condition, fish community composition, contaminants, and fish health. In our analysis of the information collected, we looked for similarities between the conditions found and potential influencing factors such as land use.
Results/Conclusions
Each of eight tributaries assessed in Tred Avon River showed some signs of stress and several Chesapeake Bay-wide issues were clearly detected, including excess nutrients, high chlorophyll a concentrations, seasonally decreased oxygen levels in bottom waters, and poor water clarity. Signs of degradation were particularly evident at the headwaters near Easton including low dissolved oxygen in bottom waters, presence of chemical contaminants above low-level NOAA thresholds, poor water clarity, and high levels of nutrients, chlorophyll concentrations, and fecal bacterial counts. Similar impacts were not observed at the mouth of the river near Oxford, another site associated with land development. Degraded water quality and the presence of chemical contaminants in sediments did not appear to significantly impact the benthic community or mummichog population. Multiple indicators of health also revealed white perch in the upper Tred Avon to be more stressed than those in the lower river. Overall, the Tred Avon River appears to be in relatively good condition based on the variables and criteria used for this assessment. Nevertheless, signs of degradation in areas affected by rapid growth and development underscore the need to protect and conserve critical fish habitat and spawning areas in the Choptank watershed and larger Chesapeake Bay.