OYSTER BOTTOMS OF MISSISSIPPI EAST OF BILOXI. 7 



indication of tlie character of the bottom, but the record was made at 

 the regular 15-second intervals observed in sounding. 



The chain, while indicating the absence or the relative abundance 

 of objects on the bottom, gives no information as to whether they 

 are shells or oysters, nor, if the latter, their size and condition. To 

 obtain these data it was necessary to supplement the observations 

 already described by others more definite in respect to the desired 

 particulars. Whenever, in the opinion of the officer in charge of the 

 sounding boat, such information was required, a numbered buoy was 

 dropped, the time and number being entered in the sounding book. 

 Another launch, following the sounding boat, anchored alongside the 

 buoy, and a quantity of the oysters and shells were tonged up, 

 separated by sizes, and counted. 



This boat at each station made a known number of '^grabs'' with 

 the oyster tongs, exercising care to clean the bottom of oysters as 

 thoroughly as possible at each grab. In a given depth of water and 

 using the same boat and tongs, an oysterman will cover practically 

 the same area of the bottom at each grab, but, other factors remaining 

 the same, the area of the grab will decrease with an increase in the depth. 



Careful measurements w^ere made and tabulated showing the area 

 per grab covered by the tonger employed on the work at each foot 

 of depth of w^ater and for each pair of tongs and boat used. With 

 these data, and knowing the number of ''grabs," the number of 

 oysters of each size per square yard of bottom was readily obtainable 

 by simple calculation. The following example will illustrate the 

 data obtained and the form of the record: 



Department of Commerce and Labor, 

 bureau of fisheries, 



Field record of examinations of oyster beds. 



General locality, Mississppi Sound. 



Local name of oyster ground, Scranton Reef. 



Date, February 1, 1911. Time, 2.00 p. m. 



Angle, H 101. Buoy No. 6. 



Depth, 4.S. Bottom, Soft, over 1Y\ 



Condition of water, Thick. 



Density, 1.016. Temperature, 19. 



Current, Stage of tide, Flood. 



No. grabs made, 8. Tongs, 10 feet. 



Total area covered, 2.S6 square yards. 



^, ^ ^ 1 f— 1 in., 20. 1 in.-3 in., 101. 



No. oysters taken^ r, - \ - .. a - 



^ I 3 m,-4m., 11. 4 in., 0, 



Quantity shells, 0. 8 dead. 



{Spat per square yard, 8.S. 

 Culls per square yard, 42.2. 

 Counts per square yard, 4-6' 



