6 



U. S. BUKEAU OF FISHERIES. 



attains an excellent growth and affords abundant lodgment for 

 minute aquatic life and for the alevins; it also provides a sufficient 

 amount of shade for the brood fish and suitable cover for their nest- 

 ing places. Large-mouthed black bass seem to prefer the fibrous 

 roots of these plants to all other nesting materials. Both plants dis- 

 appear from the warmest parts of the ponds by midsummer and are 

 replanted in the fall or following spring. Near the infloAv, especially 

 of ponds that are abundantly supplied with water, the plants thrive 

 throughout the year. The parrot-feather is more susceptible to high 

 temperatures than the foxtail. These two plants have proved so 



Fig. 1. — SpikPd water milfoil (Myri- 

 ophyllunh spycatum). Found in 

 deep water, Newfoundland to 

 Manitoba and the Northwest Ter- 

 ritory, soutli to Florida, Iowa, 

 Utah, and California. Commonly 

 known as foxtaiL (After Britton 

 & Brown.) 



Fig. 2. — Chilean water milfoil (Myri- 

 ophyUum. prosrrpinacoides). Na- 

 tive of Chile, introduced in vari- 

 ou.s localities in the United States, 

 where it is known chiefly as 

 " parrot-feather." (After Britton 

 & Brown.) 



satisfactory at Cold Springs that there has seemed little occasion to 

 experiment with other species. 



FISH LAKES, AVASHINGTON, D. C. 



Although the Fish Lakes at Washington are no longer maintained, 

 observations upon the characteristics of the plant life are valuable 

 for purposes of comparison. The bottoms of the ponds were of dark 

 fertile soil, the maximum water temperature was about 87° F., and 

 the plant growth was extremely dense. Whether the elimination of 

 some of this luxuriant growth would have resulted in a decrease in 

 the production of young fish is theoretical. This station had been 

 in operation nearly 30 years, and the lakes contained an unusually 

 large number of plants when these observations were made. 



The horn wort {Ceratophyllum dem,ersum) is especially good as a 

 food producer and shelter, is fairly good for shade, is a good oxy- 

 genator and a good aquarium plant, has little root anchorage, and 

 will grow over hard bottom. It is found in 2 to 4 feet of water, 

 extending to the surface, but not above it. It was considered the best 

 plant in the i)onds. 



