Filling of 1400 hectares of the bay by hydraulic dredging has reduced 

 the area of Boca Ciega Bay, Florida, by about 20 percent since 1950. An esti- 

 mate of the annual standing crop destroyed is 1 133 metric tons (798 kilograms per 

 hectare, dry whole weight) of seagrass and about 1 812 metric tons (1 277 kilo- 

 grams per hectare, dry weight) of associated infauna. In terms of annual pro- 

 duction, the loss of biological resources is far greater — minimum estimates are 

 25 841 metric tons of seagrass, 73 metric tons of fishery products, and 1 091 

 metric tons of infauna, exclusive of meiofauna. Natural areas remaining in the 

 bay support local and offshore fisheries and are of value for recreation, public 

 utilities, commerce, and industry. At an estimated value of $988 per hectare 

 per year, the worth of the estuarine area already eliminated is $1.4 million 

 annually. In addition, inestimable secondary losses occur, principally from 

 sedimentation, turbidity, and domestic sewage. 



173. TAYLOR, M.H., et. al., "Hydrographic and Ecological Effects of Enlarge- 

 ment of the Chesapeake and Delaware Canal. Appendix IV. Benthos of 

 Delaware Waters in and Near C and D Canal," Final Report, University 



of Maryland, National Resources Institute, Solomons, Md., Sept. 1973. 



This report presents the test results of grab and dredge samples from 25 

 stations in the Delaware part of the C and D Canal system during 1971-72. 

 Patterns of distribution within the study area were identified. Possible effects 

 of the enlargement of the canal are discussed. 



174. THORSEN, C, "Animal Migrations Through the Suez Canal in the Past, Recent 

 Years and the Future," Fie Mi-lieu, Marine Biological Laboratory, Elsinore, 

 Denmark, Supp. Vol. 22, 1968-71, pp. 841-846. 



From 1869 (completion of the Suez Canal) to 1929, only 15 valid species 

 migrated from the Red Sea to the Mediterranean and none vice versa. There were 

 extreme salinity differences, hypersalinity of the Bitter Lakes, and exceptionally 

 high summer temperatures. Nile waterflow and tidal currents previously served 

 as passage barriers, but dredging and deepening, salt dissolution, and construc- 

 tion of the Aswan High Dam facilitated migration with almost nine times more 

 Red Sea species passing the canal over the past 40 years than during the preced- 

 ing 60 years. Improved conditions for the passage of pelagic larvae increased 

 invasion of the eastern Mediterranean Basin by Red Sea biota. 



175. TRAUTMAN, M,B., "The Effects of Man-Made Modifications on the Fish Fauna 

 in Lost and Gordon Creeks, Ohio, Between 1887-1938," Ohio Jowcnal of 

 Science, Vol. 39, No. 5, Oct. 1939, pp. 275-288. 



To demonstrate the deleterious effects of dredging, the author compares 

 seining results obtained in 1938 to those made in 1887. The physical changes of 

 various parts of the creeks due to dredging are discussed. The article also 

 deals with the impact of the dredging of creeks on fish species composition and 

 abundance . 



176. TRENT, L,, "Size of Brown Shrimp and Time of Emigration from the Galveston 

 Bay System, Texas," Proceedings of the Gulf and Caribbean Fisheries Insti- 

 tute, 19th Annual Session, Nov. 1966, pp. 7-16. 



A study was made to determine the time period of emigration, the vertical 

 distribution, and the size of the juvenile and subadult brown shrimp leaving the 

 Galveston Bay system, Texas, through the Bolivar Roads tidal pass to the Gulf of 



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