56 REPORT OF THE COMMISSIOXER OF FISHERIES. 



SURVEY OF HALIBUT GROUNDS. 



The prelimmary survey of the Alaskan hahbiit grounds begun in 

 May, 1911, was continued until September, and a report on the results 

 has been issued and distributed. The steamer Albatross, with a 

 special crew of practical halibut fishermen and with the standard 

 fishing apparatus, was detailed for this work, which had for its object 

 the locating and testing of grounds either not regularly resorted to 

 by fishermen or never as yet visited by them. The grounds examined 

 extended from southeast Alaska to Bering Sea, and numerous fish- 

 mg trials were made throughout that wide area. Wliile halibut were 

 found in no great abundance on any one ground, many of the experi- 

 mental sets of trawl Imes indicated that commercial fishing would be 

 profitable. 



In order to make a thorough survey of the fishing banks of Alaska 

 and determine accurately the areas where halibut occur in paying 

 quantities, several seasons of active work will be required. An entire 

 season could profitably be devoted to each major region, so that all 

 parts of the larger banks may be tested at suitable intervals. The 

 results accomplished are chiefly important because they indicate 

 the lines along which further investigation should proceed. It is the 

 intention of the Bureau to continue this work and to make it as 

 economically useful as possible to the large interests now dependent 

 on the halibut fishery. 



FRESH- WATER MUSSEL INVESTIGATIONS. 



Investigations in the interests of the pearl-mussel fisheries of the 

 Mississippi Valley, carried on at the Fahport, Iowa, station of the 

 Bureau and in the field in connection with that station, are beginning 

 to yield results. Toward the end of the fiscal year facts were devel- 

 oped which lead to the opinion that it will soon be possible to propa- 

 gate the "wartyback" and the "niggerhead," two of the most 

 important button shells of the Mississippi and its tributaries, which 

 hitherto have not responded to cultural methods. 



Durmg the spring of 1912 the excessive and long-continued high 

 water in the Mississippi prevented the culture of mussels on a large 

 scale. In the latter part of June, however, the river conditions 

 became more favorable, a number of millions of young mussels were 

 liberated at the Fairport and Homer stations, and the results attained 

 up to that time indicated successful operations during the remainder 

 of the summer. As the fishes used for the purpose of inoculation 

 with the mussel larvae are rescued from sloughs and shallows in which 

 they would die durmg the low-water stages of summer and fall, this 

 work serves the double purpose of conserving food resources and 

 increasing the raw material for the button industry. Field investi- 



