10 BULLETIN 1098, U. 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 
affimis) 1n 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, Itisseen that Gamdusia affinis is the prevalent species. 
Tasle 4.—Dist of fishes taken in five. collections in the natural area, Bayou 
Walnut, Mound, La., 1916-17. 
| | 
| Number | Number 
Species. Common name. _ of collec- | of speci- 
| tions. mens. 
Gamipbusiataiimistec: pee ae eee eee ‘LO MinnNO Wess See ee ae Sep 5 124 
Dorosoma cepedianum........--..---------- Hickory shadssec Stee e a eee 1 20 
eponis eyanellus 222 e954 eee GTeen-SUIBHSh hisses anes nee eee 1 20 
epomis humiliss-} eee see sen eee Sunfish: S26 Gotan he eee eee 1 19 
epomis pallidus. 2ssass3 es ees See Blue-eill Sanh sheets oa 2 seo ee 1 4 
Lepomis SyimMetnicuss-==- .o2-e5-e56— see = Sunfish. ie eee See ee ee 1 te 2S 
POMORIS Spee Ss eee sss BRS Se ee ct a AED RS ee 1 3 
CarpiodeS Spaicisess se meds sees ee OSL} hall ak Se eer reas ree ae a ee 1 i 
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 larve by the 
aquatic and marginal vegetation and the vegetable débris 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. | 
