OYSTER BOTTOMS IN MATAGORDA BAY. 71 



FOOD VALUE OF WATER IX MATAGORDA BAY. 



Determinations of the food value of the water in Matagorda Bay 

 were made at all places where the density was recorded, about 120 

 stations, distributed at approximately uniform intervals throughout 

 the bay, and many additional determinations were made at the 

 anchorage of the Fish Hawk and upon the principal reefs. Ex- 

 planation of the methods adopted in this work, though useful for 

 the information of future investigators making comparative studies 

 of the food of oysters in various parts of the coast, is of little 

 general interest to the ovstermen, and a discussion of them will 

 be postponed to the end of this chapter. The subject of immediate 

 practical value is the general distribution of the food, with the 

 localities in which it is most abundant, and in the following tables 

 will be found a digest of the results obtained by the present inves- 

 tigation. 



The table on page 72 shows the stomach contents of oysters from 

 five of the principal reefs, with the food value of the water from 

 which these oysters were taken. The first column of figures repre- 

 sents (in heavy type) the average number of each organism found in 

 the oyster stomachs and (in roman type) its corresponding food 

 value. In the adjoining column are exhibited the number and food 

 value of the same organisms found in a liter (2 J pints) of the water 

 lying over and about the same reefs. It will be seen that the average 

 oyster examined contains in its stomach about the same quantity of 

 food as is found in a pint of water. 



The table on page 73 is a systematic presentation of the kinds and 

 numbers of organisms and their value as oyster food in the several 

 parts of the bay above Half Moon Light. For purposes of compari- 

 son and discussion the bay has been divided into twelve sections 

 running transversely to the shore, and for each there is shown the 

 average food value of each species of diatom, the average of the 

 section as a whole, and the average of each shore and the middle of 

 the bay. The attention of the practical oyster grower is called to 

 the totals rather than to the relative value of the individual species, 

 as consideration of the details is reserved for the more technical 

 discussion. 



The food value, so called, represents the actual volume or bulk of 

 the various species enumerated found in each liter of water taken at 

 a level of 14 inches above the bottom, the unit of measurement 

 employed being the one-millionth part of a cubic millimeter. A 

 cubic millimeter is about six ten-thousandths of a cubic inch. In 

 cases of organisms which from their small numbers or other causes 

 are unimportant as food, the number only is shown, as it was 

 considered unnecessary to calculate the volume. 



