216 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



a request made by the president of our association. Prof. G. Brown 

 Goode informed us that in the Chesapeake Bay oysters perish, when 

 the saltness, for some time, is less than 1.3 per cent. According to 

 observations made by Dr. H. A. Meyer,* the saltness of the sea-water 

 on the east coast of Schleswig-IIolstein only goes below 1.3 per cent, 

 in spring and summer, when large quantities of fresh water are emptied 

 into the Baltic from the rivers and streams. Iu autumn and winter 

 the percentage of saltness is higher, as much as 2 per cent, and more, 

 in deep places. On the 15th September, 1882, I found a saltness of 1.8 

 per cent, in the surface-water near the island of Aaro, where the Ameri- 

 can oysters have been placed. 



Wherever the European oysters form natural beds, and also in basins 

 where they are cultivated or kept for the market, the average saltness 

 of the water is greater. , 



Per cent. 



The average saltness on the Schleswig oyster-beds is 3 to 3. 3 



Near Whitstable and Heme Bay, mouth of the Thames 3. 1 to 3. 2 



In the river Boach, southeast coast of England 3. 1 



In the Bay of Arcachont 3 



In the Ostend oyster-basins 2. 9 



In the basins of Tremblade, mouth of the Sendre, Western 



France 2. 5 



As the North American oyster is found as far south as the coast of 

 Texas and as far north as New Brunswick, it evidently possesses the 

 faculty of accommodating itself to different temperatures. According 

 to Ingersoll,! the oyster-beds near New Brunswick are during winter 

 covered with ice. This great adaptability of the North American oyster 

 to sea-water of different temperatures suggests the question whether 

 there are not varieties of it which cannot only stand a low temperature, 

 but also water possessing but a small degree of saltness, qualities 

 which are peculiar to all the marine animals living in the Baltic. The 

 oysters set out near the island of Aaro were selected without any spe- 

 cial regard to these qualities. They belong to the variety which is 

 found in the latitude of New York, especially near Long Island. They 



* H. A. Meyer: Untersuchu/ngen iibcr physikalische Verhaltnisse der westlichcn Thtiles 

 der Ostsee. Kiel, 1871. 



tin the Deutsche Fischerei-Zeitung for August 1, 1882, J. Boeck says: " Iu France 

 oysters are cultivated in the mouths of rivers; iu Southwestern France, in inlets 

 having brackish water. * •* * There is reason to hope that by means of natural- 

 ized and acclimatized oysters, oyster-culture may be successfully introduced iu our 

 many inlets having brackish waters." 



In this connection I would say that the saltness of the water of the Baltic, between 

 Eiigen and the Greifswalder Oie, is only .72 per cent. ; in the Greifswalder Bodden, .65 

 per cent. ; and in the hafts still less. It appears from this that it is not safe to draw 

 a conclusion, as to the saltness of sea-water from a similarity in the configuration of 

 the coast. 



t E. Ingersoll: "The oyster industry," in The History and Present Condition of 

 the Fishery Industries, prepared under the direction of Prof. S. F. Bainl, by G. Brown 

 Goode. Washington, 1881. 



