56 



OYSTER BOTTOMS IN MATAGORDA BAY. 



The observations made at the Fish Hawk anchorage in 8 feet of 

 water off Three Mounds signal give the results shown in the follow- 



ing tables 



Date. 



Average 

 tempera- 

 ture. 



Date. 



Average 

 tempera- 

 ture. 



January 1-15, inclusive 



Degrees. 

 52.9 

 51.8 

 45.5 

 47.3 

 60.3 



March 16-31, inclusive 



Deqrees. 

 68.2 



January 16-31, inclusive 



! April 1-15, inclusive 



71.2 



February 1-14, inclusive . . 



April 16-30, inclusive 



73.4 



February 15-28, inclusive . 



Mav 1-11, inclusive 



77.2 



March 1-15, inclusive 









Month. 



Number of days on which temperature 

 was between — 



Days 

 observed. 





30-40. 



40-50. 



50-60. 



60-70. 



70-80. 



January 



1905. 



1 

 3 



10 

 22 

 10 



20 



3 



17 







81 



February 







28 



March 



4 



5 



25 

 11 



31 



April 





30 



Mav 1-11 









11 















The temperature observations at large in the bay, owing to the ex- 

 igencies of the work and weather, were not made with sufficient reg- 

 ularity and system to be readily digested, their main purpose being 

 the correction of the densities shown on the chart. A comparison 

 with the corresponding day's observations on the Fish Hawk shows 

 a general agreement within one or two degrees, excepting, as might 

 be expected, that the shoal water warmed more rapidly with the ad- 

 vance of spring. During the winter, which was an unusually severe 

 one, the temperature dropped on several days below the freezing 

 point, but on the whole the operations of oystering w T ere not nearly 

 so much interfered with as they are every year on the oyster beds of 

 Chesapeake Bay and northward. In this respect the oyster fields of 

 Texas and other localities on the gulf coast have a distinct advantage 

 over those of the Atlantic coast. 



The prime importance of the temperature of the water lies in its 

 relation to spawning and the spawning season. The oyster, as is 

 shown by the writer's observations on various parts of the gulf and 

 Atlantic coasts, does not begin to spawn until the temperature of the 

 surrounding water reaches about 70° F. An inspection of the table 

 will show that this average temperature was not reached until April, 

 and it was past the middle of that month when it rose permanently 

 above 70° ; before then there were occasional periods when it fell for a 

 day or two below that point. During the winter particularly the 

 changes of temperature, even at a depth of 8 feet, were sudden. 

 From 8 a. m. February 12 to 8 a. m. February 14 the temperature fell 

 from 48° F. to 32° F., a decrease of 16° in forty-eight hours, and 

 from 8 a. m January 12 to 8 a. m. January 15 it fell 18°, from 59° to 



