The Bureau of Fisheries 



203 



gathered data for each stream exam- 

 ined' upon the following points : Char- 

 acter of the country through which it 

 flows, volume of water which it carries, 

 general character of the water as to 

 clearness, purity, and temperature ; the 

 species of fishes, mollusks, reptiles, ba- 

 trachians, and other animals inhabiting 

 the stream or found about it, and the 

 abundance, distribution, and habits of 

 each ; also the species of aquatic plants, 

 their distribution, abundance, and their 

 relation to the fishes of the same waters. 



The primary and immediate objects 

 of these investigations are to determine 

 what species of fishes each stream al- 

 ready contains, what are the conditions 

 favorable to their well-being, and whether 

 the conditions, physical and biological, 

 are favorable for the introduction of 

 other species. Investigations of this 

 kind have been carried on in about 

 twenty different states — Maine, Ver- 

 mont, New York, West Virginia, In- 

 diana, Texas, Iowa, Minnesota, South 

 Dakota. North Dakota, Wyoming, Mon- 

 tana, Idaho, Washington, Oregon, Cali- 

 fornia, Florida, Tennessee, and Nebraska. 

 As man}' of these investigations were 

 made in response to resolutions of Con- 

 gress calling upon the Bureau to deter- 

 mine the desirability of establishing fish- 

 cultural stations in certain states, it can 

 be seen that a wide area had to be cov- 

 ered, and that the investigations were 

 necessarily hurried and incomplete. Oc- 

 casionally , however, it has been possible 

 to confine the observations for a longer 

 period of time to a limited area, and 

 more thorough work has resulted. 



Not until 1899, however, was any such 

 work undertaken under really favorable 

 conditions. The Commissioner desired 

 to secure knowledge regarding the ecol- 

 ogy of the great multitude of small gla- 

 cial lakes of the northern states. It was 

 therefore decided to select a suitable lake 

 and make such a study of it as would 

 serve as a model for the investigation of 

 all similar lakes. Lake Maxinkuckee, 



in northern Indiana, was known to meet 

 all the requirements exceptionally well 

 and it was selected. 



There is not space to give in detail 

 the outline of the investigations carried 

 on at this lake. It must suffice to say 

 that the lake was studied along man}' 

 lines. A thorough physical survey was 

 made and a very accurate map pre- 

 pared. Thousands of soundings were 

 taken and the hydrography of the lake 

 carefully studied. Temperature obser- 

 vations were made and the chemical 

 and physical characteristics of the water 

 determined. The species of fishes, other 

 animals, and plants in the lake w 7 ere cata- 

 logued and careful studiesof their habits, 

 relations, and interrelations were carried 

 on for one entire year, especial atten- 

 tion being paid to the food, enemies, and 

 breeding habits of the food-fishes. More 

 is now known of this lake, perhaps, than 

 of any other lake in America, and more 

 has been learned of the habits of the 

 species inhabiting it than we know for 

 any other region. 



3. Experiments in Oyster Ctdture. — 

 Another investigation which this Bureau 

 is now conducting and which promises 

 very great economic results pertains to 

 the artificial feeding of oysters. 



It has been observed that oysters 

 grow much more slowly on some beds 

 than on others; that in certain places 

 they fail to fatten. These places were 

 usually on overcrowded beds, and some- 

 times good results could be secured by 

 transplanting or thinning out. Quali- 

 tative and quantitative study of the 

 diatoms (which constitute the food of 

 oysters) on beds where the oysters fat- 

 ten well, and on other beds where they 

 fatten poorly, showed that the number 

 of diatoms per liter of water was very 

 much greater in the former than in the 

 latter. 



It was therefore believed that if the 

 supply of diatoms could be increased 

 on the unproductive beds the oysters on 

 them would grow and fatten. Experi- 



