IV-571 



Some kinds of commercial fishing require the use of trawls or the set- 

 ting of traps or nets that must be left for some time. The use of such 

 devices restricts other uses while the devices are in place, but there 

 is no permanent appropriation of estuarine waters or space. The major 

 conflict is with recreation in that recreational boating must be 

 excluded from areas where fishing gear is near the surface. 



Where there is conflict, the scene is set for trade-off, i.e., a willing 

 substitution of one activity for another. The scene is equally set for 

 uncompensated damage where one user group precludes the activities of a 

 second unrelated user group but does not reimburse them for damage. 

 Actual documented examples of use damages are difficult to find. One 

 major reason is the basic fact that has permeated much of the discussion 

 of economic and social values: Many estuarine values are not quantifi- 

 able. While damages to a commercial enterprise, such as commercial 

 fishing, can be quantified in terms of the economic loss, the essentially 

 intangible values of recreation and estuarine habitat are difficult to 

 measure. 



Recreational loss would have to be measured in terms of how many people 

 don't swim or go boating in the Potomac River because it is polluted. 

 It is far easier to find out how many people do go there even if it is 

 polluted; even these values are hard to find. 



The value of estuarine habitat is just as difficult to establish. There 

 are now about 5.5 million acres of important estuarine marsh and wetland 

 habitat remaining in the estuarine zone of the United States. Perhaps 



