98 REPORT OF COMMISiJiONEK OF FISH AND FISHERIES. 



encouraging results liavc attended the observations made in San Fran- 

 cisco Bay with resi)ect to the breeding ol' the Athmtic coast oj'ster, and 

 an important scientific investigation has been conducted off the ^vest- 

 ern coast of Mexico and Central America, under the direction of Prof. 

 Alexander Agassiz. 



The field operations on the Atlantic coast have been directed chiefiy 

 to the study of the oyster-grounds of Long Island Sound, of Tangier 

 Sound in Maryland and Virginia, and of the coast of South Carolina. 

 Extensive surveys were made in Long Island Sound with respect, 

 mainly, to the conditions of the bottom, the natural enemies of the oys- 

 ter, and the varying distribution of the set of S])at. The absence of any 

 pollution in the oyster-ground waters was also fully demonstrated by 

 careful physical and chemical observations. The extent and causes of 

 the deterioration of the oyster beds in Chesapeake Bay has been made 

 the subject of a special investigation, which is still in progress, Tangier 

 and Pocomoke sounds having been selected for the first exandnations. 

 The in(]uivies in South Carolina were conducted for the purpose of as- 

 certaining the character and distribution of the natural oyster-cultural 

 resources and of determining the proper measures for their develop- 

 ment. The work was completed in the course of a single winter, and 

 has afforded very satisfactory results. Arrangements have also been 

 made for the preparation of a series of reports descriptive of the meth- 

 ods of oyster-culture practiced in European countries, which will, it is 

 hoped, be at least suggestive to American oyster-growers. 



The study of the physical characteristics of the coast waters off" the 

 Northern Atlantic States, especially in the region traversed by the 

 mackerel during their seasonal migrations, has been taken up for the 

 first time in a thoroughly comprehensive manner, and has now been 

 actively prosecuted during two summers. While the principal part of 

 this work has been limited to the southern New England coast, a series 

 of observations has also been carried southward to A^irginia. These 

 inquiries will have an equal bearing upon the habits of. all other migra- 

 tory fishes which resort to this region during a greater or less part 

 of each year, and nearly all of the important economic species which 

 enter into the fisheries there are of this character. 



Among the investigations relating to the fresh waters the one of 

 most direct importance has probably been the study of the salmon 

 rivers of Alaska with respect to the natural history of the salmon, the 

 threatened depletion of the schools by the destructive methods of cap- 

 ture now in use, and the measures necessary to preserve this extensive 

 food Kupply. The observations were made on Kadiak and Afognak 

 islands, and on Wood Itiver at the head of Bristol Bay. The fresh- 

 water systems have also been examined in eleven ditferent States and 

 Territories, as follows: The Yellowstone National Park, Colorado, Utah, 

 Missouri, Arkansas, Iowa, Wisconsin, Indiana, Ohio, Kentucky, and 



