The physical environment of Lake Pontchartrain was found to be 

 characterized by moderate temperature, generally low salinity, and 

 very high turbidity, although considerable variations in these factors 

 were noted. 



The species of fishes and invertebrates that were considered are 

 identified as follows: bull shark, longnose gar, spotted gar, alligator 

 gar, bigeye herring, gulf menhaden, gizzard shad, threadfin shad, 

 southern bay anchovy, gaff-topsail catfish, sea catfish, blue catfish, 

 channel catfish, Atlantic needlefish, striped mullet, silverside, 

 yellow bass, largemouth bass, common jack, freshwater drum, silver 

 perch, sand squeteague, spotted squeteague, spot, Atlantic croaker, 

 black drum, red drum, gulf sheepshead, pinfish, southern flounder, 

 hogchoker, common rangia (clam), white shrimp, river shrimp, and blue 

 crab. (H.D. and author's summary). 



Keywords: estuarine community, fishes, invertebrates, food habits, 

 Louisiana 



III-E-4 



Odum, W.E., and E.J. Heald. 1975. The detritus-based food web of an 



estuarine mangrove community. Pages 265-286 jn^ L.E. Cronin, ed., Estuarine 



research. Vol. 1. Academic Press, New York. 



This paper is an attempt to construct a conceptual model of the food 

 web of an estuarine mangrove community. The objective is to ascertain 

 the importance of vascular plant detritus to the heterotrophic community. 



From stomach-content data most of the important organisms of the estuary 

 were arranged into the following groups: herbivores, omnivores, and 

 three levels of carnivores. Most species function at more than one 

 trophic level . 



Of about 120 species examined, roughly one-third can be classified 

 as detritus consumers. These are defined as organisms whose digestive- 

 tract contents averaged at least 20 percent vascular plant detritus 

 by volume on an annual basis. These detritus consumers included herbiv- 

 orous and omnivorous species of crustaceans, mollusks, insect larvae, 

 nematodes, polychaetes, and a few fishes. They appeared capable of 

 digesting algae, portions of vascular plant detritus particles, micro- 

 organisms and, perhaps, dissolved substances sorbed upon inorganic 

 particles. 



A schematic diagram of the North River food web suggests that the 

 principal flow of energy is along the route: mangrove leaf detritus, 

 bacteria and fungi, detritus consumers, lower carnivore, higher 

 carnivores. CA.A.) 



Keywords: detritus, food web, estuaries, mangroves 



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