10 



BULLETIN 1098, V. S. DEPARTMENT OF AGRICULTURE 



FISHES OF THE REGION. 



A survey of the fishes of this region was made by the United States 

 Bureau of Fisheries in cooperation with this work. This survey was 

 intended to cover the distribution of the top minnow {Gambusia 

 a-ffkiis) in this region; the possible presence of fishes other than this 

 minnow that would be useful in mosquito destruction ; the fishes valu- 

 able as food in the deeper and permanent areas of water ; the survival 

 of Gambusia in the impounded area in Bayou Walnut ; and the possi- 

 bility of establishing in the impounded area fishes that would be of 

 value for food to the tenants on the plantation. This work was ac- 

 complished during 1916 and the early part of 1917. The fishes col- 

 lected in Bayou Walnut under natural conditions are listed in Table 

 4. It is seen that Gambusia affinis is the prevalent species. 



Taele 4. — List of fishes taken in five collections in the natural area, Bayou 

 Walnut, Mound, La., 1916-17. 



Species. 



Common name. 



Number 

 of collec- 

 tions. 



Number 

 of speci- 

 mens. 



G ambusia affinis 



Dorosoma cepedianimi. 



Lepomis cyanellus 



Lepomis humilis 



Lepomis pallidus 



Lepomis symmetricus. . 



Pomoxis sp 



Carpiodes sp 



Top minnow 



Hickory shad 



Green sunfish 



Sunlish 



Blue-gill sunfish. 

 Sunfish 



12i 

 20 

 20 

 19 

 4 

 3 

 3 

 1 



A point of special interest in connection with the natural condi- 

 tions of the bayou is the fact that Gambusia is found in connection 

 with general breeding of Anopheles. The breeding of these mosqui- 

 toes in the presence of comparatively large numbers of this minnow 

 is accounted for by the protection afforded the mosquito larvae by the 

 aquatic and marginal vegetation and the vegetable debris upon the 

 surface of the water. Further, the partially dry condition of the 

 bayou at certain seasons provides isolated pools and water in hoof- 

 prints of animals and in mud cracks from rains, to which the fish 

 do not have access. 



A complete list of the fishes collected in this region, not including 

 the impounded area in Bayou Walnut and the Mississippi River, is 

 shown in Table 5. 



