The north coast of the Gulf of Mexico has been 

 described as being a barren region for benthic algae 

 (Taylor 1960); however, some macroscopic algae do 

 exist. Since no data for the Chenier Plain study area 

 have been found, the following information is based 

 on studies in southeastern Louisiana. The most 

 common genera in saline waters are Enteromorpha 

 and Ectocarpus (table 4.19). These two forms are 

 most abundant on the banks of streams and lakes and 

 in quiet pools. They are found from early November 

 to mid-April and early May, but peak abundance 

 occurs in January. 



Table 4.19. List of benthic marine algae from in- 

 land open water habitat of south- 

 eastern Louisiana (Day et al. 1973). 



Chlorophyta 



Blidingia marginata 



B. minima 



Chaetemorpha linum 



Cladophora dalmatica 



Enteromorpha clathrata 



E. flexuosa 



E. linza 



E. ramutosa 



Entrocladia testarum 



Pseudendoclonium submarinum 



Rhizoclonium kochianum 



Phaeophyta 



Ectocarpus intermedins 

 E. siliculosus 

 Giffordia mitchelliae 



Rhodophyta 



Bargia atropurpurea 

 Bostychia radicans 

 Erythrocladia subintegra 

 Erythrotrichia carnea 

 Polysiphonia subtillissima 



Diversity of vascular plant species increases with 

 decreasing sahnity in the inland open water habitat. 

 For brackish water bodies along the Louisiana coast, 

 Chabreck (1972) reports a coverage of about 1% for 

 rooted submerged aquatics. Common floating plants 

 in inland freshwater bodies include water hyacinth, 

 alligatorweed, duckweed, and waterlettuce. These 

 plants only do well in quiet, slow-moving waters. When 

 they are washed downstream from the freshwater 

 areas into saline zones, the salt water kills them. Al- 

 ligatorweed is reported in fresh marshes in the Cal- 

 casieu Basin at a frequency of 26% (Chabreck 1972). 

 Both water hyacinth and alligatorweed are introduced 

 species that have become major pests in coastal water- 

 ways. 



4.9.2 CONSUMERS 



Zooplankton identified in the inland open water 

 habitat are Usted in the appendbc 6.3. Many of these 

 were identified by Denoux (1976) for the Calcasieu 

 Basin and by Gillespie(1971) for Sabine and Calcasieu 

 passes and the lower Mermentau River. 



Stickle et al. (1975) sampled a number of loca- 

 tions in the brackish parts of the Calcasieu Basin for 

 benthic organisms. Sampling stations and the macro- 

 invertebrates identified are shown in appendix 6.3. 

 Freshwater benthic organisms are also listed in this 

 appendix. 



The inland open water habitat, as defined, ranges 

 from highly saline to completely freshand, therefore, 

 has a rather high vertebrate species richness. There are 

 species of amphibians and turtles ranging from the 

 saltwater diamondback terrapin to the southern 

 painted turtle, a species that is confined to completely 

 fresh water. Seven species of watersnakes are also rep- 

 resented. Wading birds and shorebirds occur primarily 

 around the periphery of larger water bodies, while 

 waterfowl use open water for feeding and/or resting. 

 The southern bald eagle, an endangered species, nests 

 near water and feeds on fishes. Mammals in this habi- 

 tat are represented by four species of bats, the nutria, 

 muskrat, otter, and, in areas near the coast, the Atlan- 

 tic bottle-nosed dolphin. The West Indian manatee, 

 an endangered species, has been periodically recorded 

 in lower estuaries. 



The finfish species richness is also somewhat 

 higher in the inland open water habitat than in the 

 nearshore Gulf. In addition to the majority of species 

 which divide their time between the two habitats, 

 there are a few species which are strictly estuarine 

 (Gulf killifisli, diamond killifish) and a number of 

 species which are limited to fresh or nearly fresh water 

 (bowfin, carp, smallmouth buffalo, and largemouth 

 bass). In trawl and seine catches from 18 inland open 

 water habitat stations in the Chenier Plain (Perret et 

 al. 1971), the Gulf menhaden, the Atlantic croaker, 

 and the bay anchovy were the most abundant finfishes. 

 Perry (1976), reporting results of trawl and rotenone 

 catches from the Rockefeller Wildhfe Refuge (4 to 

 15.5%o sahnity), also found the Gulf menhaden to 

 be dominant in numbers. Red drum was the dominant 

 fish in terms of weight (fig. 4.35). Other common fishes 

 were the bay anchovy, striped mullet, shad, Atlantic 

 croaker, and southern flounder. Lists of representative 

 finfishes and other vertebrate species, found in the in- 

 land open water habitat are in appendix 6.3. 



4.10 NEARSHORE GULF HABITAT 



Water bodies of the nearshore Gulf habitat are 

 characterized by smooth, gently sloping bottoms, with 

 occasional mudflats and sand ridges that are subject 

 to relatively strong wind and wave action. The depth 

 gradient runs roughly parallel to the coast ; east to west 

 variations occur because of differences of interaction 

 with the river basins and because of the net westward 

 drift of the longshore current. The area covered by 

 the nearshore Gulf habitat (fig. 4-36) is 3,713 km^ 

 (1,434 mi2), 65% of the Chenier Plain aquatic system. 



205 



