cannot long survive at the present land loss rate. Additionally, the fishing industry may 

 be damaged by measures taken to reduce this rate. 



Saltwater intrusion, as a result of reducing the discharge of fresh water, can 

 severely affect shrimp production. Reduction of the brackish zone limits the shelter and 

 food available to maturing shrimp. The increase in estuarine salinities as a result of land 

 loss and concomitant saltwater intrusion may increase shrimp harvest over a short period 

 because of enlarged nursery grounds (Barrett 1975). A point will be reached, however, 

 when there are no longer enough marshes to nourish the historic nursery grounds; then, 

 shrimp harvest will decline permanently. 



As 75 to 85 percent of the species of fishes and macroinvertebrates inhabiting our 

 coastal areas are estuarine dependent, changes in our estuaries, such as salinity increases 

 and loss of detritus from marsh reduction, would damage these stocks. 



A case in point is the effect of the Toledo Bend Reservoir on the marine animal 

 communities in Sabine Lake (Whitehead and Perret 1974). Seasonal pulses of fresh water 

 into this lake prior to flow control consisted of high discharges during early spring and 

 low discharges during the summer. This water cycle is normal for Louisiana streams, and 

 apparently ideal for shrimp and other marine species. Since 1967, high freshwater 

 discharges into Sabine Lake occur throughout the summer as a result of control structure 

 operation. The impact of this change in water cycles has been dramatic on shrimp 

 production in this lake. Prior to 1967, annual shrimp catches in Sabine Lake were as 

 large as 385,000 kg (850,000 lb). Since 1967, annual shrimp catches in the lake were 

 31,000 kg (67,000 lb) with an average annual catch of 9,000 kg (20,000 lb) between 1967 

 and 1977. 



Oyster populations are reduced as higher salinities resulting from coastal erosion 

 allow inhabitation by predators and pathogens. An instance which demonstrated the 

 advantages of freshwater introduction to oyster production was reported by the Louisiana 

 Wildlife and Fisheries Commission (I960). The Bayou Lamoque structure, which was 

 completed in 1956 for the purpose of improving oyster habitat east of the Mississippi 

 River, discharged 6 X 10° m^ (500,000 acre-feet) of river water into the adjacent 

 marshes in 1957. Following this discharge, oyster yields increased about 100% and 

 survival of young oysters improved because of a reduction in predators and pathogens and 

 an increase in nutrients. 



Many of the uses of our marshes result in impacts which physically destroy and 

 reduce the quality of these marshes. Users of the marshes are regulated by licenses and 

 permits, however, the rate of land loss with its related adverse effects on animals and 

 habitats continues to increase. 



Management of an animal population is an effective tool for preserving end 

 propagating fish and wildlife— for example, the alligator has now been taken off the 

 endangered species list in Louisiana. Years ago the alligator was becoming endangered 

 primarily because of overhunting. Laws were then enacted which prohibited the taking 

 of alligators. During the period that these animals were protected, populations 

 increased. The protection of animals can easily be accomplished by establishing seasons, 

 bag limits and methods of kill. 



The habitat of the various animals using the marshes and estuaries is not well 

 protected; habitat maintenance is as important to the survival and well being of fish and 



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