28 U. S. BUREAU OF FISHERIES. 



Gambusia, is employed so successfully or on so large a scale? How- 

 ever, much yet remains to be done. The slightly brackish and fresh 

 marshes of the Delaware and other rivers and the estuaries of Chesa- 

 peake Bay have scarcely been touched, and most of the work done 

 there has taken little account of the fishes that are at hand to help. 

 It seems probable that on many tracts where actual reclamation work 

 has not been or is not to be done methods similar to those employed 

 on the salt marshes, with modification of the form and arrangement 

 of the ditches to suit the different conditions, would be equally suc- 

 cessful. 



Fundulus Tietei^oclitus has also been recommended for transplan- 

 tation into upland ponds, and some experiments of this kind have been 

 made, but the author has been unable to follow the results sufficiently 

 to form a definite opinion. Undoubtedly this killy is sufficiently 

 adaptable and hardy to withstand the change, but its behavior in 

 relation to the tides is so pronounced that it seems hardly probable 

 that it will thrive and propagate entirely away from their influence. 



It is very desirable, however, that such experiments should be 

 carried to a conclusion. 



TRANSLUCENT KILLIFISH (Fundulus diaphanus). 



The translucent killifish is found from Maine to Cape Hatteras 

 along the coast as well as inland and is continued westward to the 

 Mississippi River by the subspecies menona. Though found in the 

 salt waters of the back bays and throughfares this is particular!)^ 

 a brackish and fresh-water species, abundant in the river systems of 

 the New England and Middle Atlantic States, and unlike the common 

 killifish is a common fish of the upland waters. It is exceedingly 

 abundant in many of the streams and ponds of the Delaware River 

 drainage and in similar situations in northern New Jersey and 

 southern New York. 



The author's studies on the translucent killifish have been limited 

 chiefly to observations made in northern New Jersey, though the fish 

 was met with at Philadelphia and in Palisades Park. Like the other 

 killies it is gregarious and frequents the shallows, where it feeds at 

 both bottom and surface, and penetrates into the intricacies of the 

 banks and among open vegetation. As it breeds freely in landlocked 

 fresh waters it is readily established in upland ponds. 



The writer knows of no detailed account of the food of the eastern 

 form, but the subspecies riienona has been thoroughly studied by 

 Pearse (1918) and Forbes and Richardson (1908). The former sum- 

 marizes the contents of 149 stomachs, in percentages, as follows 

 (p. 262) : 



Fish embryos, 0.8 ; insect eggs, 0.8 ; insect larvse, 23.4 ; pupse, 1.7 ; adult Insects 

 2.7 ; mites, 3 ; amphlpods, 14.1 ; ostracods, 15.7 ; copepods, 4.9 ; cladocerans, 15.3 

 Sphseridse, 0.4 ; snails, 3.5 ; oligochsetes, 2 ; nematodes, + ; plant remains, 5.5 

 algae, 0.9 ; silt and dStoris, 4.2. 



The top minnow ate 36 per cent entomostracans and 28 per cent insects, as 

 weU as amphipods, plant remains, the debris from the bottom and the surface 

 of plants, mollusks, etc. Forbes and Richardson (1908) reported the food of 

 this species to be insects, amphipods, snails, and plant seeds. The large per- 

 centages of ostracods, oligochaetes, and Chydoridfe and the species of insect 

 larvae found in the present investigation indicate that the top minnow frequently 

 feeds near the bottom or among vegetation. 



No mosquito larvse are reported to have been found, though chiro- 

 nomid larvse were common. 



