REPORT OF COMMISSIONER OF FISII AND FISHERIES. 5 



practicability of exteiidiiig tlie area of production by artificial i)laiit- 

 iiigs, as lias been done in Long Island Sound. The survey was first 

 taken up in Tangier Sound, wbere a similar inquiry bad been conducted 

 by the Coast Survey about twelve years before, in the expectation that 

 the results obtained would afibrd the data for a very instructive com- 

 parison. By July 1, 1S91, the delineation of the ])eds had been about 

 coni])leted, and the dredging work was soon to be commenced. 



During both summers the oyster beds of Long Island S(mnd have 

 been subjected to (extensive investigations, and nuich information has 

 been secured regarding the natural features of the region, tlie habits 

 of starfishes and of other enemies of the oyster, and the conditions of 

 spatting during the two seasons. The summer of 1800 was chiefly 

 si)ent in making a physical and chemical examination of the waters of 

 the sound, the former inquiry being undertaken with the cooperation 

 of the Superintendent of the Coast Surrey, This had for its object to 

 ascertain, by a series of careful current observations, the extent of the 

 nujvement of water through the soun<l and the adequacy of the How to 

 prevent stagnation and consequent harm to the oyster beds. The 

 chemical studies consisted in makijig tests of the waters in all parts of 

 this area, both in inclosed and exposed positions, to determine its sani- 

 tary condition. The result of these researches proves very conclusively 

 that no damage need be apprehended from the present condition of the 

 waters, and that a sufficient flow takes place to insure, under existing 

 circumstances, the prompt removal of polluting matters; but it is not 

 to be denied that the sewage and other sources of contamination might 

 be so increased as greatly to endanger the welfare of the oyster- 

 grounds. 



Dr. Bashford Dean, of Columbia College, New York, an exi)ert on 

 the subject of oyster-grounds, who left this country near the close of 

 the last fiscal year for an extended visit in Europe, has been commis- 

 sioned to study the methods of oyster-culture now practiced in Euro- 

 jK'an countries, and to prepare an illustrated series of reports regarding 

 those matters, which, it is expected, will be at least suggestive to 

 American oyster-growers. 



The physical inquiries in the mackerel region oft' the southern New 

 England coast under the <lirection of Prof. William Libbey, jr., referred 

 to in the last annual report, were conducted during a part of July and 

 August, 1889, and again during the summer of ] 800. The former seasou 

 the work was performed by means of the schooner Gra7npus alone, but 

 during the latter the Coast Survey steamer BlaJce was detailed to act 

 in cooperation with the Grampus, and, through the courtesy of the 

 Light-ITouse Board, a party of observers was also stationed on the 

 Nantucket New South Shoal liglit ship. Parallel lines of observing 

 stations were carried seaward fiom the coast for distances of 130 to 150 

 miles, the lines being 10 minutes of longitude apart and the stations 10 



