DETERIORATION OF AMERICAN OYSTER-BEDS. 31 



In danger of soon becoming so. It rests with us, then, to determine 

 that question with as much accuracy as possible, and, should we find 

 the evil an existing one, to show the best means of removing it. 



First, are the beds of Maryland and Virginia deteriorating ? 



It is only possible to speak with entire accuracy of a limited por- 

 tion of the entire area covered by oysters in these States, but, as the 

 infiuences affecting the beds are very similar, it may be assumed with 

 safety that the condition of the beds of one district will be, approxi- 

 mately, that of all ; at least, it is certain that beds or localities pre- 

 senting like peculiarities will be in a similar condition as regards 

 reproduction. The only locality in this country which has been thor- 

 oughly studied lies on. the eastern shore of Chesapeake Bay, opposite 

 the mouth of the Potomac River. The investigation was carried on 

 by the Coast and Geodetic Survey during the summers of 1878 and 

 1879, and included the survey of the beds of Tangier and Pocomoke 

 Sounds, the measurement of the depth of water over the beds, and 

 direction and force of currents ; the ascertainment of the character 

 of the bottom, the constituents and specific gravity of the water on 

 both flood and ebb tides ; the temperature during the summer months 

 or spawning-season ; the effect of gales, ice, and freshets ; and of the 

 fishery either with dredges or tongs. In general terms, as elaborate a 

 study of the beds of the locality was made as was possible. 



Tangier and Pocomoke Sounds were selected on account of the 

 immense extent of their oyster-beds, and because they permitted the 

 study of all the varying conditions affecting the oysters. 



The two sounds are arms of Chesapeake Bay, and lie opposite the 

 mouth of the Potomac River, on the eastern side of the bay. Tan- 

 gier Sound extends north from Watt's Island, at its entrance, about 

 thirty-six miles, and is separated from the bay by a chain of low, 

 marshy islands ; it receives from the eastern peninsula the waters of 

 several creeks and rivers, all of considerable importance. The shoals 

 on each side of the channel are covered with oyster-beds, and, where 

 the beds do not exist, the oysters are scattered either in groups or 

 singly. They are also found as continuations of the beds, or scat- 

 tered in the straits separating the different islands and joining the 

 waters of the sound to those of the bay. On each side of the channels 

 of the tributaries of the sound oyster-beds are also found, and, gener- 

 ally speaking, it may be said that throughout Tangier, in depths be- 

 tween one and six fathoms, oysters may be taken in varying numbers. 

 The entrance to Tangier Sound is also the entrance to Pocomoke 

 Sound, Watt's Island lying between the two at their confluence. Po- 

 comoke stretches to the northward and eastward, extending into the 

 peninsula, while Tangier lies along its western boundary. 



Pocomoke Sound is twelve and a half miles long and about nino 

 miles broad near the middle, decreasing in breadth near the head 

 and entrance. The channel is narrow and tortuous, and the main body 



