OYSTER BOTTOMS OF MISSISSIPPI SOUND, ALA. 7 



a continuous indication of the character of the bottom, but the record 

 was made at the regular 15-second intervals observed in sounding. 



The chain, while indicatmg the absence or the relative abundance 

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

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

 obtain these data it was necessary to supplement the observations 

 already described by others more definite in respect to the desu^ed 

 particulars. Whenever, m the opinion of the ofhcer in charge of the 

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

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

 Another launch, followmg the sounding boat, anchored alongside the 

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

 rated 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 mcrease in the depth. 



Careful measurements were made and tabulated showing the area 

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

 depth of water 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, Mississippi Sound, Ala. 

 Local name of oyster ground. Pass des Huitres. 

 Date, December 29, 1910. Time, 1.05 p. m. 

 Angle, C 193-C 194. Buoy No. 2. 



Depth, S feet. Bottom, Hard. 



Condition of water, Clear. 

 Density, 1.015. Temperature, 58° F. 



Current, Stage of tide. Flood. 



Tongman, Bryant. 



No. grabs made, 6. Tongs, 10 feet. 



Total area covered, 2.4 sq. yds. 



No. oysters takenJ-^ i^"' ^- ^ ^^-'^ "^^ ^^9- 

 [3 in.-4 in., 33. 4 in., 0. 



Quantity shells, 0. 



iSpat per square yard, 2.5. 

 Culls per square yard, 45.4.-^ 

 Counts per square yard, 13.7. 



