C-33 



Reasons for Decline : 



1. Limited habitat. Much of its habitat was drowned out in Ice 

 Age Melt. 



2. Very small population. 



3. Possible slow natural change of aquatic environment, (e.g. 

 water chemistry, stream contours, stream bottom, ground 

 water, etc.) . 



4. Evolutionary changes. Species is at the periphery of range 

 of the subgenus . 



5. Potential pollution by housing and commercial developments 

 near streams. Presently streams are not polluted, and those 

 nearby developments are not apparently threatening. Potential 

 damming of creeks. 



6. Extreme fluctuations in creeks could reduce population, as 

 could siltation. 



7. Conowingo Dam, downstream on Susquehanna, has not had any 

 apparent effect on the darters in Deer and Swan Creeks. 



Protective Measures Taken : 



None other than to request biologists and ichthyologists not to 

 collect or disturb fishes and habitat. 



Protective Measures Proposed : 



1. Acquire stream banks and bed for several miles on either 

 side of main center of population and maintain as wooded, natural 

 sanctuary for Maryland Darter. This would prevent dams flooding up- 

 stream and any developments would have to be set back from creek. 



2. Precautions are needed to assure proper handling of sewage, 

 storm water run-off, and other wastes from nearby residential and 

 commercial development to prevent seepage into creeks. 



3. Begin investigations into life history of darter, including 

 population movements, to determine possible migratory or seasonal 

 movements in and out of creeks. 



4. Prevent fish collectors from decimating existing populations. 



