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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



1,700 meters by the United States Coast and 

 Geodetic Survey steamer Bache in Marcii 1914. 

 Salinities of two surface samples collected a little 

 farther east in January and February 1919 were 

 reported by Mayor (1922). Stations taken by 

 the Danish research vessel Dana across the Hav'ana 

 section in 1922 provided data for a salinity profile 

 (Nielsen 1925; Schmidt 1929; Jacobsen 1929). 

 Composition of two surface samples collected in 

 July 1922 in the Gulf Stream south of the Dry 

 Tortugas was reported by Lipman (1929). 



The Havana section was studied again in Feb- 

 ruary 1932 on the Yale Oceanographic Expedition 

 aboard the schooner Mabel Taylor (Parr 1935). 

 Expeditions from the Woods Hole Oceanographic 

 Institution aboard the research vessel Atlantis 

 have made studies of the Havana section in March 

 1934 (Bulletin Hydrographique, 1935), February 

 and April 1935 (Bulletin Hydrographique, 1936; 

 Seiwell 1938), March 1938 (Montgomery 1941), 

 and May 1939 (Riley 1939). The vertical distri- 

 butions of salinities across the Havana sections in 

 1922, 1932, and 1934 were summarized in profiles 

 by Parr (1935, pp. 42-44, 71). Below 100 meters 

 the isohalines generally sloped downward toward 

 the Cuban coast. In the middle of the Straits 

 the salinity generally increased from 35.83°/oo at 

 the surface to 36.68°/oo at 200 meters, then de- 

 creased to a minimum of 34.87°/oo at 800 meters, 

 and thereafter increased only slightly to 34.97°/oo 

 at 1,600 meters. 



The next most thoroughly studied part of the 

 Gulf of Mexico is the Yucatan Channel where the 

 Caribbean Current enters the Gulf between west- 

 ern Cuba and Mexico. This section was studied 

 in 1922 from the Dana (Schmidt 1929; Jacobsen 

 1929), in February 1932 from the Mabel Taylor 

 (Parr 1935), and from the Atlantis in May 1933 

 (Bulletin Hydrographique, 1934; Parr 1937; Rake- 

 straw and Smith 1937) and March 1934 (Bulletin 

 Hydrographique, 1935; Parr 1937). The vertical 

 distributions of salinities across the Yucatan 

 Channel in 1933 and 1934 were summarized in 

 profiles by Parr (1937, pp. 42-43). Here, also, 

 the isohalines generally sloped downward toward 

 the Cuban coast. The vertical distribution of 

 salinity was similar to that described above for 

 the Havana section. Comparison of the average 

 temperature-salinity correlation curves for the 

 Yucatan Channel and the Havana section of the 

 Straits of P'lorida led Parr (1935) to conclude'that 



the water mass entering the Straits of Florida is 

 identical with that which passed through the 

 Yucatan Channel except for a very small layer of 

 "Gulf type" water at the surface on the left 

 (Florida) side of the main current. 



Parr's (1935) report on the expedition of the 

 Mabel Taylor, February to April 1932, included a 

 map showing the locations of the 68 stations oc- 

 cupied in the Gulf, complete temperature and 

 salinity data, salinity profiles of 5 sections across 

 the main parts of the Gulf, maps of salinity dis- 

 tribution in upper 50 meters and at 200 meters, 

 graphs of vertical distribution of salinity, and 

 temperature-salinity correlation curves. The ex- 

 pedition was not provided with unprotected re- 

 versing thermometers and therefore had no 

 means for accurate determination of the depths of 

 observations. The highest salinities (above 

 36.25°/oo) in the upper 50 meters were found in 

 the shallow waters off the west coast of Florida 

 and the Campeche Bank. Most of the offshore 

 water in this surface layer had salinities between 

 36.00°/oo and 36.25°/oo. Low salinities (below 

 33°/oo) were found along most of the northern 

 regions of the Gulf, and very low (less than 24%©) 

 salinities were found near the mouth of the 

 Mississippi River and to the west from the delta 

 region. At a typical station in the western Gulf 

 (25°46' N., 92°3r W.) the salinity decreased 

 slightly from 36.16°/oo at the surface to 36.12°/oo 

 at 50 meters, then increased to the maximum of 

 36.31 °/oo at 100 meters, then decreased to the 

 minimum of 34.87°/oo at 600 meters, then in- 

 creased slightly to 34.92°/oo at 800 meters, below 

 which it remained practically constant down 

 to 3,000 meters. 



Dietrich (1939, p. 119) used the 1932 data from 

 the Gulf of Mexico to prepare another map 

 showing the distribution of the maximum salinities, 

 regardless of depth. This showed a continuous 

 layer of high salinity (above 36.7%o) water in 

 most of the Caribbean Sea, the northern half of 

 the Cayman Sea, and extending northward into 

 the Guif to 26°0()' i\. and 89°20' W. 



The Atlantic occupied stations along several 

 sections of the central and western Gulf in 

 February to April 1935 (Bulletin Hydrograpliique, 

 1936). A map showing the locations of these 

 stations was published by Vaughan (1937, p. 21). 

 Vertical distribution of salinity at a typical station 

 in April 1935 in the western Gulf (25°40' N., 



