PROGRESS Ilsr BIOLOGICAL INQUIRIES, 19 2 7 223 



3. According to data obtained during 1927, the spawning season 

 begins in the latter part of April or first of May and extends through 

 August and sometimes into September, depending upon various fac- 

 tors. During this period there occur two distinct periods of great 

 spawning activity and sometimes others less pronounced. In 1927 

 the first of these began about June 22 and lasted until July 1. The 

 second, less distinct than the first, began about July 15 and lasted 

 until July 22. In this year a third period, still less distinct than 

 either of the others but quite apparent, began about August 7 and 

 lasted until August 17. 



The fact that oysters may be found on the piles that support 

 beacons, lighthouses, and the like, or on any other place of attach- 

 ment that was observed in the sound, indicates that the distribution 

 of larvae is very general. This fact should make feasible the estab- 

 lishing of reefs on what is at present barren bottom. 



4. The salinity in Mississippi Sound as a whole is subject to wide 

 seasonal fluctuation. Except for a maximum period of three months, 

 the salinity in the west end of the sound (which produces the bulk 

 of the oysters) was below 20. Several of the reefs in this region were 

 covered by fresh water during the spring months. In the Back Bay 

 of Biloxi, Avhich generally is considered one of the best oyster-produc- 

 ing regions on the Mississippi coast, the salinity was above 20 for a 

 period of three months, and then in only one-third of the bay. The 

 duration of the existence of fresh water, or very low salinity, is 

 shorter in the Pascagoula region than in any other oyster-producing 

 section of the sound. For a period of eight to nine months the 

 salinity here is between 20 and 30. In spite of this fact and the 

 abundance of suitable bottom, this region is the most neglected of all 

 as far as planting operations are concerned. 



5. The area of bottom in Mississippi Sound that is either suitable 

 at present or may be made suitable by the proper application of 

 cultch is approximately 100 square miles in extent. Of this amount, 

 about 23 square miles produces oysters in marketable quantities at 

 this time. 



6. Planting, particularly of seed oysters, often is done carelessly 

 or improi^erly. No attempt is made to separate clusters of seed into 

 single individuals. 



Pamlico Sounds North Garolhm. — With the cooperation of the State 

 fisheries commission, a hydrographic survey of oyster bottoms in 

 Pamlico Sound and adjacent waters was carried out by H. R. Seiwell. 

 The results of this investigation, which lasted from October, 1926, 

 until September, 1927, may be summarized as follows : 



1. The dccily and seasonal variation of salinity in Pamlico Sound 

 depends upon the direction and velocity of the winds. 



2. The highest salinities are encountered in the eastern side of the 

 sound and the lowest in the northern part. 



3. The average salinity in Pamlico Sound is 19.4 parts per 

 thousand. 



4. The direction and velocity of the currents, except those in the 

 inlets, are determined by the direction and velocity of the winds as 

 well as b}'^ the location of the area in question. 



5. The turbidity of the water is directly dependent upon the depth 

 and character of the bottom. 



