Research now is more advanced, better funded, and the evidence continues 

 to illustrate the importance of estuaries for sustaining fish and shellfish. 



HABITAT ALTERATION 



For the majority of species studied, the availability and capacity of 

 habitat is a major limiting factor of species abundance. The rate of loss of 

 habitat has been greatly reduced in Florida recently by protective regula- 

 tions. No longer can developers move freely into a marsh or estuary and in- 

 discriminately dredge and fill to create waterfront (canal) home sites such as 

 that done in Boca Ciega Bay near St. Petersburg. Although dredging determined 

 to be "in the public interest" continues, the massive projects of the 1950's 

 and 1960's now are a rarity. Habitat loss today is more subtle; an acre or 

 two, a small boat channel, a causeway, all of which have cumulative effects. 

 Not only is the area of wetlands being reduced, but the productivity of the 

 remaining wetlands is declining. The decline in habitat productivity is most 

 frequently caused by (1) loss or diversion of freshwater from estuarine sys- 

 tems and (2) sewage, chemical, industrial, and thermal pollution, and oil 

 spills. 



With the increased demand for coastal fishes and the proven dependence of 

 these fishes on estuaries, the need for increased habitat protection in coast- 

 al wetlands is paramount. Some of the current water and land use changes and 

 developments or practices that are still damaging the estuaries and which 

 should be eliminated or at least regulated are: (1) diversion of freshwater 

 inflow from the estuaries, (2) diking or impounding estuarine marshlands for 

 mosquito control, (3) spraying of insecticides on watersheds, wetlands, and 

 shallow estuarine shorelines for mosquito control, (4) the construction of 

 causeways or other structures for highways, and (5) navigation channel mainte- 

 nance. 



Some land management practices, which usually are several miles upstream 

 from an estuary, also may unfavorably alter habitats. Principal examples are: 

 (1) clear cutting of forests or woodlands, which alter surface runoff, stream 

 flow, and groundwater supplies, (2) excessive use of pesticides, herbicides, 

 and fertilizers in agricultural operations, and (3) damming or otherwise al- 

 tering river flow patterns. 



In view of man's destruction and alteration of habitats, many possibil- 

 ities for restoration have been examined. For example, spoil islands or erod- 

 ing dunes can be vegetated to increase stability and maintenance of natural 

 habitat. Permits issued for land alteration (in the public interest) may re- 

 quire mitigation for habitat loss. 



Under certain conditions, some natural habitats may become more produc- 

 tive by the addition or construction of new habitat features. For example, 

 the construction of artificial fishing reefs on flat or low relief bottoms 

 attracts and concentrates fish so that they are more available to sport fish- 

 ermen. The construction of shell reefs in appropriate waters may sharply 

 increase the area for attachment of oyster spats and increase oyster abun- 

 dance. Oyster beds or reefs constructed by the Florida Department of Natural 

 Resources in Apalachicola Bay since 1949 now account for a major share of pro- 

 fitable oyster beds. This and other forms of restoration of loss or damaged 



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