exception of the largest tuna clippers and purse seiners few U.S. com- 

 mercial fishing vessels exceed 80 ft in length and a substantial number 

 are 60 ft or less. This does not guarantee that foreign fishing vessels 

 can always be distinguished on the basis of size alone, but it does 

 suggest that a detection technique designed to detect 100-ft and larger 

 vessels will be able to detect virtually all foreign fishing vessels 

 under any circumstances and will discriminate to some extent against 

 detection of most U.S. fishing vessels under many circumstances. 



3. Vessel Traffic Density 



A characteristic of the enforcement environment, which was 

 mentioned earlier, is the existence of a relatively dense pattern of 

 maritime traffic within which the fishing vessels of interest are im- 

 mersed. No extensive investigation of this characteristic was made. 

 However, Figure 1 is a plot of postulated ship traffic in 1980, which 

 shows that, in general, the maritime traffic pattern can be expected to 

 be dense along the coasts, i.e., in the vicinity of the 200-nmi fishing 

 zone. The data plotted in Figure 1 are based on a distribution by 

 trade routes and preferred operating regions of an at-sea vessel postu- 

 lation given in Table 5. ' Note that fishing vessels are the largest 

 component of the forecast at-sea population. This information is in- 

 cluded to underscore the fact that identification and classification 

 functions will be important and challenging parts of the enforcement 

 problem. 



This discussion assumes that remote sensing "observables" are a function 

 of vessel size. As it turns out, this was found to be true for the 

 techniques found worth examination in this survey. 



Figure 1 and Table 5 are from Reference 3 



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