SOME EFFECTS OF HYDRAULIC DREDGING AND COASTAL DEVELOPMENT 



IN BOCA CIEGA BAY, FLORIDA ' 



BY JOHN L. TAYLOR AND CARL H. SALOMAN, Fishery Biologists 



BUREAU OF COMMERCIAL FISHERIES BIOLOGICAL LABORATORY 



ST. PETERSBURG BEACH, FLA. 33706 



ABSTRACT 



Filling of 1,400 hectares (3,500 acres) of bay by hy- 

 draulic dredging has reduced the area of Boca Ciega 

 Bay, Fla., by about 20 percent since 1950. .\n estimate 

 of the annual standing crop destroyed is 1,133 metric 

 tons (798 kg. per hectare, dry whole weight) of sea grass 

 and about 1,812 metric tons (1,277 kg. per hectare, dry 

 weight) of associated infauna. In terms of annual 

 production, the loss of biological resources is far 

 greater — minimum estimates are 25,841 metric tons of 



sea grass, 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. .\t an estimated value of $988 

 per hectare per year, worth of the estuarine area already 

 eliminated is $1.4 million annually. In addition, in- 

 estimable secondary losses occur, principally from 

 sedimentation, turbidity, and domestic sewage. 



Boca Ciega Bay is a part of Tampa Bay, Fla., 

 where coastal development and progressive de- 

 terioration of water quality have adversely influ- 

 enced plant and animal production. This report 

 describes some biological and physical changes that 

 followed alteration of the bay and compares estu- 

 arine conditions in dredged areas with those in 

 relatively undisturbed areas. 



Hydraulic dredging became an accepted means 

 of creating coastal upland in Florida about 1920, 

 and lias since proved an efficient means of provid- 

 ing waterfront real estate of premium value. 

 Dredging was not a serious threat to coastal re- 

 sources until after 19.50 when coastal construc- 

 tion started on a large scale, especially along the 

 lower east coast and the low-energv* strand of the 

 west coast from Tamj^a Bay soutliward. Profit and 

 permissive attitudes toward the sale of submerged 

 land contrilnited to rapid dispo.sal of vast public 

 holdings along much of Florida's 14,400 km. (9,- 

 000 statute miles) of tidal coastline. Bay filling 

 has been little regulated, and in most situations 



biological and recreational resources of estuarine 

 waters have been disregarded by coastal devel- 

 opers and governing authorities (Davis, 195(5; 

 Brunn and De Grove, 1959; Kidd, 190.3). 



Legislation to control dredge-fill projects in 

 Florida api)eared fii"St in 1957 (Section 253.122 

 Florida Statutes, 1957), and the following year 

 all such projects liecame subject to Federal review 

 (Fish and Wildlife Coordination Act, P.L. 85- 

 fi24) . X'nfortunately, luider these laws the sale and 

 development of submerged land remained largely 

 arbitrary and most efforts to stop landfills in estu- 

 aries have been unsuccessful (Arnold, 1967). 



Guidelines for apjjraisal of estuarine areas were 

 proposed by Thompson ( 1961), and more positive 

 measures are now lieing taken to conserve marine 

 resources and provide for their rational use in 

 Florida as well as in other parts of the country 

 and aln-oad (Florida Statutes, chapter 67-393; Gil- 

 mour, 1965; Hutton, 1964; Tukey, 1965; Cain, 

 1966; Caldwell, 1966). Encouraging, too, is the 



Published October 1968. 



I Contribution No. 47, Bureau of Commercial Fisheries Biological Labora- 

 tory, St. Petersburg Beach, Fla. 3370b. 



FISHERY BULLETIN: VOL. 67, NO. 2 



213 



