Environmental Impacts 



This section discusses general impacts of an expanding aquaculture 

 industry. 



Changes in Land Use 



One of the strongest impacts of an expanding aquaculture industry 

 will be the changes in land use and resultant changes in habitat 

 for various terrestrial, wetland dependent, or aquatic organisms. 

 Generally, the net value to wildlife would increase at upland 

 sites, but decrease at wetland sites. The various forms of 

 aquaculture also have different impacts on land use. Intensive 

 culture systems use less space than extensive systems to produce 

 equal numbers of fish. 



Upland areas 



The conversion of upland areas into aquaculture facilities could 

 result in some wildlife and esthetic losses. The most detrimental 

 losses would be of forests or old fields and their attendant fauna 

 and flora. Few forested areas are converted to aquaculture because 

 of high costs and physical problems associated with making the 

 conversion. Old fields are more likely to be converted. However, 

 the conversion of monoculture croplands to earthen ponds would 

 create habitat for a variety of water dependent wildlife. 



Wetland areas 



Aquaculture facilities sited in the highly productive coastal 

 wetlands could be destructive to natural ecosystems. Many species 

 of fish and crustaceans use the estuarine nursery zone during 

 juvenile stages of their life cycles. Fish and wildlife agencies 

 generally oppose aquaculture programs for the coasta] wetlands 

 because of this loss of valuable habitat. Inland swamps and 

 marshes also furnish valuable habitat for wildlife. Present local. 

 State, and Federal regulations make it difficult to convert 

 wetlands to other uses. 



Open-water areas 



The nature of the aquaculture facility determines to a great extent 

 whether or not it displaces natural aquatic habitat. The exclusive 

 use of an area for cultured species would eliminate its value as a 

 nursery for wild species. On the other hand, the use of a portion 

 of the bottom or water column for oysters or other shellfish may 

 enhance the natural fisheries. 



Net enclosures for salmon have been observed to degrade the bottom 

 immediately underneath the nets but not to adversely affect 

 adjacent bottom areas. 



