THE UNITED STATES BUREAU OF FISHERIES. I409 



will undoubtedly result from recent changes in the methods of the fishery, the 

 Bureau is convinced that the preservation of the American sponge industry 

 will depend upon cultivation; and as it is estimated that about $1,500,000 

 worth of sponges were taken in Florida during the past year, the failure of the 

 fishery would be a serious commercial loss to the State. 



In cooperation with the Rhode Island Fish Commission, the Bureau has 

 developed new methods of lobster and soft-shell clam culture which are being 

 applied with success in New England. Experiments with the hard-shell clam 

 are now in progress at Beaufort. 



Important work recently undertaken is an effort to establish mussel culture 

 in the Mississippi Valley. The supply of mussels in those waters, on which is 

 based a pearl-button industry valued at about $5,000,000 per annum, with an 

 investment of $6,000,000, is being rapidly exhausted, and the mussel fishermen 

 and manufacturers recognize that without scientific cooperation of the Gov- 

 ernment the business is doomed to early extinction. The Bureau in one season's 

 work has practically, though not conclusively, shown a method by which the 

 pearl mussels can be propagated, and is demonstrating that the work can be 

 carried on at a comparatively small expense in connection with the already 

 established operations in rescuing fishes from the overflowed lands, the fishes 

 reclaimed being employed, without injury to themselves, in the dissemination 

 of the larvae of the mussels. There have been liberated 25,000 fish, bearing 

 about 25,000,000 young mussels ready to drop and begin their independent 

 existence, and already past the stage when they are most subject to fatality. 

 The work is also capable of application to waters under private control and 

 will probably become a source of respectable revenue to farmers and others 

 whose property embraces streams, ponds, and lakes. The importance of this 

 work is urgently insisted upon by the National Pearl Button Manufacturers' 

 Association, which embraces practically the entire capital invested in the 

 business. 



In the field of fish diseases great progress has been made in the extension 

 of knowledge of the causes of many of the fatalities which sometimes make a 

 clean sweep of the hatcheries and which heretofore could not be adequately 

 coped with because their etiology was not understood. The services of the 

 scientific staff in this regard have been not only of great benefit to the Govern- 

 ment, but are highly regarded and frequently availed of by state and private 

 fish-culturists. Among the direct material aids rendered to fish culture in the 

 past four or five years are the following: (i) Determination of the cause and 

 remedy for the fatal malady known as the "gas disease," which at one station 

 killed 1,200,000 brook-trout fry out of 1,300,000 on hand; (2) isolation of a 

 bacterial organism producing a fatal disease in trout, and discovery of a possible 

 remedy; (3) determination of the cause of a fatal protozoan disease in trout: 



