Report of the Board of Shell Fish Commissioners. 1 5 



METHODS OF OYSTER SURVEY.* 



INFORMATION FURNISHED. 



Before beginning the actual survey of oyster grounds the Com- 

 mission is furnished by the United States Coast and Geodetic Sur- 

 vey with projections, constructed on a scale of I part in 10,000 

 (approximately 6 1-3 inches to a statute mile), showing the shore 

 line of the localities to be surveyed and the plotted positions of the 

 triangulation stations. The Coast and Geodetic Survey has a party 

 in the field to erect signals above, and determine the position of 

 such triangulation stations as are needed by the hydrographic en- 

 gineers for use in making the survey of the oyster grounds. 



Prior also to making a survey of any section the local assistant, 

 appointed by the County Commissioners, gives information as to 

 the approximate location and extent of the oyster grounds of the 

 section so they can be indicated in pencil on the boat sheets. This 

 information greatly expedites survey operations in that it makes 

 surveys of barren bottoms unnecessary, and saves cost of erecting 

 unnecessary shore stations beyond the limits of the natural oyster 

 bars. 



EQUIPMENT. 



The equipment for conducting the survey of the oyster grounds 

 and crabing bottoms includes boats, instruments, etc., a brief list 

 and description of which follows : 



The launch "CANVASBACK," 2 with a coxswain and machinist, 

 is furnished by the United States Bureau of Fisheries. This launch, 

 42 feet long, 9-foot beam, has a draft of three feet and is hence well 

 adapted for work on oyster grounds the boundaries of which extend 

 into water as shallow as four feet. 



The "ANGLE," a dead-rise bateau, 24 feet in length, belonging 

 to the Commission, is used for surveying grounds situated in water 

 too shallow for the advantageous use of the launch "CANVAS- 

 BACK." Before beginning field work in 1909 this boat was 

 equipped with a four horse-power gasoline engine. 



* Modified from former report, in conformity with changes in methods. 

 2 For a detailed account of the work and equipment of the Investigator,- see 

 pages 37 and 116 of First Report. 



