INTRODUCTION 
DDT has been used extensively for mosquito abatement in saltmarsh 
areas in recent years. As a result there have been numerous reports of 
possible hazards and of actual harm to wildlife and fish populations. 
Until now, however, there has been almost no study of the broad consequences 
of these mosquito control operations. . 
This report covers the first season's investigations of a proposed 
two~ or three-year cooperative study on the biological consequences of DDT 
sprayings on a salt marsh at the Brigantine National Wildlife Refuge, 
Oceanville, New Jersey. 
Purposes of the study were to ascertain effects on fish and wildlife 
of sprayings comparable to those applied to salt marshes for control of 
mosquito larvae and to look for methods of allaying or possibly eliminating 
damage to the more important forms of life. To a considerable degree, 
investigations in 1949 were exploratory and were directed toward the search 
for suitable methods to determine DDT effects upon marshland wildlife 
populations. 
opraying Program 
Plans for this study resulted from cooperative arrangements with 
several federal and state agencies. The Bureau of Entomology and Plant 
Quarantine of the U. S. Department of Agriculture supplied the insecticide 
and the plane for aerial application. The New Jersey Agricultural Experiment 
Station investigated effects upon insect pests of the area, particularly 
the saltmarsh mosquitoes and the greenhead fly. Personnel of the New Jersey 
Fish and Game Division gave active assistance during several phases of the 
study.e 
Reasons for choosing the Brigantine Refuge site were threefold: 
(1) it was eonsidered typical of marsh areas commonly subjected to spraying, 
(2) it has representative populations of saltmarsh wildlife and the organisms 
upon which they depend for food, and (3) studies could be conducted on it 
without interference to or from other activities or objectives. 
| Four study areas of 50 to 100 acres were selected to be treated 
by airplane aj. rates of 1.6, 0.8, Ol, and 0.2 pounds of DDT per acre 
respectively.-/ Each area was sprayed twice, the first application occurring 
between August 17 and 19, mostly at high tide, and the second on September 15 
and 16 at low water. 
1/ Hereafter, these plots or dosages are designated as the 1.6, 0.8, 
0.4, and 0.2 plots or dosagese 
