maining8,539haor 21,100a (7.0% of the 1952 area) 

 were converted to open water by a combination of 

 natural and cultural processes. Shoreline erosion ac- 

 counts for 675 ha (1,668a), but the conversion of the 

 rest of the wetlands to open water is unexplained. 

 Elsewhere on the Chenier Plain, excluding Calcasieu 

 Basin, this unexplained loss rate for wetlands is about 

 0.10% (2% since 1952). The higher rate of wetland 

 loss in the Sabine Basin probably reflects hydrologic 

 and salinity modifications resulting from construction 

 of the extensive network of canals, and the Toledo 

 Bend and Sam Raybum reservoirs. 



Other habitat changes since 1952 reflect urban 

 growth in the basin. Urban needs were responsible for 

 the loss of 2,339 ha (5,780a) of agricuhural land be- 

 tween 1952 and 1974 (table 3.72). 



Effects on renewable resources : The influence of 

 cultural activities on renewable resources in the Sabine 

 Basin has reduced both habitat quality and quantity. 

 The continued loss of natural wetlands will inevitably 

 result in a further decline of those living resources de- 

 pendent upon those habitats. 



In addition to the indirect effects of habitat loss, 

 the discharge of organic and inorganic pollutants can 

 kill aquatic species. Sections of tlie ship channel, 

 tlie GIWW, and the Neches and Sabine rivers are 

 seriously contaminated, especially with Iiigh organic 

 loads, colifomi bacteria, and organic toxins (Diener 

 1975). Much of the industrial pollution from the de- 

 veloped areas appears to bypass Sabine Lake by flow- 

 ing througli the ship channel and GIWW. 



Decline in the harvest of croakers, black drum, 

 red dmm, flounder, spotted sea trout, oysters, and 

 shrimp in Sabine Lake (table 3.73) can be related to 

 past development and reservoir construction. Presently 



the only commercial harvest of any significance is 

 blue crab (table 3.74). In 1974 and 1975 it too had 

 decreased to about one-half the 1973 peak. 



Additional considerations in Sabine Basin are 

 sport fishing and hunting. Comparison of available 

 sustainable supplies of sportfish and game with the 

 estimated demand indicates that for all species the 

 demand far exceeds the supply (sec. 3.5). Not only 

 does the human population of the basin directly ex- 

 ploit the living resources, but cultural activities at the 

 same time cause habitat degradation and loss. 



Heavy industrial use of water has resulted in local 

 declines in ground-water levels. Ground wateris drawn 

 from the Chicot Aquifer, which is large enough to 

 sustain high withdrawal rates. Nevertheless, saltwater 

 intrusion is a serious problem in southeastern Texas 

 because of highpumpage rates (Baker and Wall 1976), 

 and the fresh-saltwater interface is moving northward 

 at the rate of 10 to 80 m/yr(33-262 ft/yr)(Harder 

 et al. 1967). 



3.6.7 EAST BAY BASIN 



General Features. East Bay Basin is located on 

 thesouthwestemendof the Chenier Plain and is a part 

 of the Galveston Bay system, which also includes West 

 Bay, Trinity Bay and Galveston Bay (fig. 3-5 1 and 

 plates lA and IB). East Bay is a narrow estuary, 

 10 km (6.2 mi) wide at its western end, paralleling 

 the coast and extending eastward about 37 km (21 mi) 

 from Galveston Bay. It is bound on the north by fresh 

 and brackish marshes and on the south by Bolivar 

 Peninsula, which separates it from the Gulf. This 

 peninsula is about 30 km (18.6 mi) long, varying in 

 width from 1 to 10 km (0.62 to 6.2 mi) (Lard 1978). 

 It is separated from Galveston Island on the southwest 



Table 3.73. Commercial fish landings (kg) for Sabine Lake for 1970-1975''. 



1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 



Croaker Nl'' NI 91 



Black drum 1,591 273 273 727 545 364 



Red drum 4,000 1,182 6,091 2,864 7,227 4,136 1,818 



Flounder 

 (unclassi- 

 fied) 9,091 3,636 1,000 227 2,682 227 



Sea cat- 

 fish (gaff- 

 topsoil) 273 500 



Spotted 

 sea trout 6,136 2,364 7,545 1,955 7,091 21,000 



Unclassi- 

 fied 



For food 9,045 1,364 500 



227 



1,818 



Total 11,727 3,546 23,091 18,046 17,909 25,908 5,364 227 



2,772 



1,045 



Source: National Marine Fisheries Service. Texas landings, annual summary, 1970-1975, and 1969. Texas landings, 1968-1972. 



U.S. Fish and WiUllife Service. 

 NJ - not included in 1963 and 1964 as a separate species. 



140 



