EFFECTS OF WETLAND CHANGES ON THE FISH AND 



WILDLIFE RESOURCES OF COASTAL LOUISIANA 



David W. Fruge 



U.S. Fish and Wildlife Service 

 Lafayette, LA 



ABSTRACT 



The vast wetlands of the 

 Louisiana Coastal Region (LCR) are 

 of national importance to fish and 

 wildlife. These wetlands winter 

 one-fourth of the North American 

 dabbling duck population, a large 

 portion of the Mississippi Flyway's 

 diving ducks, and over 400,000 

 geese. Coastal Louisiana also sup- 

 ports numerous other migratory 

 birds, many of which nest in its 

 wetlands. The LCR marshes produce 

 the largest fur harvest in North 

 America, and support the largest 

 volume of estuarine-dependent fish 

 and shelfish landings in the United 

 States. Fish and wildlife-related 

 recreation in the LCR is also ex- 

 tensive, including 11.9 million 

 man-days of saltwater fishing and 

 crabbing in 1975 and 676,000 man- 

 days of waterfowl hunting during the 

 1977-1978 season. Prior studies 

 documented an annual land-loss rate 

 of over 16.5 mi /yr (42.7 km yr) 

 in the LCR. More recent investiga- 

 tions indicate that this rate of 

 wetland loss more than doubled since 

 1956. Wetland deterioration, which 

 is partially attributable to natur- 

 al causes, has been greatly accel- 

 erated by human influences such as 

 navigation channel excavation, 

 agricultural drainage, and construc- 

 tion of mainline Mississippi River 

 levees that have prevented fresh- 

 water and sediment overflow into 



adjacent subdelta marshes. Contin- 

 ued wetland deterioration may lead 

 to serious declines in estuarine- 

 dependent fish and shellfish har- 

 vest, fur catch, waterfowl habitat, 

 and related fish and wildlife pro- 

 ductivity. The U.S. Fish and Wild- 

 life Service (USFWS) has long 

 advocated freshwater diversion for 

 habitat improvement in the Missis- 

 sippi Deltaic Plain Region and is 

 presently participating in the 

 evaluation of several freshwater 

 diversion sites being investigated 

 by the U.S. Army Corps of Engineers. 

 Preliminary USFWS estimates indi- 

 cate that the monetary value of 

 fish and wildlife productivity can 

 be increased by more than $4.5 

 million/yr with a single large-scale 

 freshwater diversion structure that 

 would introduce Mississippi River 

 water into the Lake Pontchartrain- 

 Lake Borgne Basin of southeast 

 Louisiana. Because federally fi- 

 nanced public works projects have 

 played a major role in wetland de- 

 terioration in the LCR, mitigation 

 of these losses through the federal 

 public works program would seem 

 appropriate. 



INTRODUCTION 



AREA SETTING 



The Louisiana Coastal Region 

 (LCR) contains a vast expanse of 



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