PERCENT LOSS (RADIOGRAPH) 



Figure 6. Comparison of wood-loss estimates from exposure panel weights versus visual assessments of radiographs 

 from 1985-1986. These data were collected as part of the Exposure Panel Program at the Millstone 

 Nuclear Power Station. 



Numerical abundance. The Millstone area has two general groups of marine woodborers: crustaceans 

 and molluscs (Table 4). The crustaceans are represented in our data by two native taxa: IJmnoria spp., 

 isopods, and Chelura terebrans, an amphipod. Because of the difficulties in identifying Limrtoria to the 

 level of species, these "gribbles" have been lumped together at the generic level. Recruitment of Limnoria 

 onto panels was greatest during the Feb-Aug (88-623 individuals/panel) and May-Nov 

 (up to 1670 individuals/panel) exposure periods (Fig. 8). Of the five sites monitored, GN and WP sup- 

 ported the greatest populations of these isopods. During the May-Nov exposure period, WP had 5 times 

 more Limnoria than any other site and nearly 9 times more C. terebrans. This latter species has a 

 commensal relationship with dense populations of limnorids, since the chelurids primarily feed on the thin 



17 



