12 REPORT OF C0MMISSIONP]R OF FISH AND FISHERIES. 



hardl}' substantiated ))y reliable data, and the extermination of the herds 

 met with opposition in many (quarters. The Commission was final]}' 

 asked by the California authorities to make an investigation of the 

 food and feeding habits of the sea lions with a view to determining 

 the point at issue. This was according!}^ undertaken by an agent of 

 this office, assisted by a representative from both the California ))oard 

 of fish commissioners and the California Academy of Sciences, and 

 was carried on during July and August. As thorough an inquiry as 

 practicable was made, from which it appears that the sea lions did not 

 do much damage except at the mouth of the Columbia River, but 

 further study of some aspects of the case will be necessary before 

 a definite conclusion can be reached. 



At the request of oyster-growers of Tuckerton, N. J., a representa- 

 tive of the Commission was detailed to investigate the destruction of 

 oyster beds in that vicinit}^ by drum-fish. These fish feed on the seed 

 oysters, which are the thin-shelled eastern forms, and cause enormous 

 losses, many extensive beds being practicallv depleted. In one case, 

 where some 20,000 bushels of oj/sters had been planted, an examina- 

 tion showed that over 80 per cent had been destroyed. Various expe- 

 dients have been tried or suggested without much success, and it would 

 seem that it will be necessary to use heavy-shelled oysters, which are 

 strong enough to resist the drum-fish, for seed, rather than the thin- 

 shelled ones. The former, however, at this particular locality do 

 not attain so satisfactory a growth. 



The ])iological surve}' of the Great Lakes has been continued, the 

 work still being confined to Lake Erie with headquarters at the station 

 of the Commission at Put-in Bay. Special attention was given to the 

 white-fish, wall-eyed pike, carp, and sturgeon 



The investigations of the fisheries of the Territory" of Hawaii, called 

 for by act of Congress, were partially completed during the summer 

 of 1901, most of the islands being visited, the fishery methods and 

 laws studied, a statistical canvass made, and a large and interesting 

 collection of fishes obtained. A preliminarv report was made to the 

 President in July, 1902, and by him submitted to Congress. As 

 stated elsewhere, the investigation of the deeper waters around the 

 islands is now being continued by means of the steamer Albah'oss. 



Among other investigations may be mentioned the continuation of 

 the biological study of the quinnat salmon in California, a further 

 in(]uiry as to the results of introducing new species into certain lakes 

 in Idaho and ITtah, an inquiry into the geographical distribution of 

 trout and salmon in the waters of Maine, and biological inv(>stigations 

 of certain waters of New York and New Jersey. 



The subject of the diseases of fishes has received considera})le atten- 

 tion, the time of one assistant being entirely devoted thereto. Mor- 

 talitv from causes little understood in the (i()\'(M'rimen( hatcheries and 



