16 



U. S. BUREAU OF FISHERIES. 



June 24, eight weeks later, there were removed from this pond 6,000 

 fingerlings, ranging in length from 3 to 4 inches. The rapid growth 

 and large number of fingerlings reared is attributed to the presence 

 of exceptional quantities of small amphipod crustaceans (Gamma- 

 rus) , which are a valuable fish food ; and the abundance of this food, 

 although attributable to the quality of the water, seems to be depend- 

 ent also upon the presence and character of the aquatic vegetation. 

 The present superintendent believes that of all of the plants above 

 mentioned Myriophyllum has proved to be the most satisfactory. " Its 

 growth is abundant and the stalk being rather tender it is easily re- 

 moved from the ponds with rakes or grass hooks attached to long 

 handles, whenever it is desired to prepare for seining operations. 

 After a pond has been allowed to season this plant is easily reestab- 

 lished by simply covering a handful of the stalks with a shovel full 



Fig. 28. — Various-leaved wa- 

 ter milfoil (, Myriophyllum 

 heterophylhim) . Found in 

 ponds, Ontario and New 

 York to Florida, Texas,, and 

 Mexico. (After Britton & 

 Brown. ) 



Fig. 29. — Cat-tail {Typha TatifoUa). 

 ^"'ound in mar.shes throughout Nortli 

 America, except in extreme north. 

 Also in Europe and Asia. (After Brit- 

 ton & Brown.) 



of earth at intervals of from 3 to 6 feet. If this is done in the late 

 summer or early fall, there is a fine stand of vegetation by the follow- 

 ing spawning time in March and April." While some of the other 

 plants are still there, he would prefer the one species only. 



SAN MARCOS, TEX. 



At the San Marcos (Tex.) station one of the milfoils (Myrio- 

 phyllum heterophyllum) is preferred to all other water plants. A 

 former superintendent stated that here some of the water lilies, 

 Chara, and the cat-tail (Typha latifolia) would, if permitted, 

 crowd out all other plants of value. He regarded frogbit [Uhho- 

 clmiium. horsfordi)^ because of its exuberant growth, as the most 

 objectionable of all the plants found in the pond. He believed water 



