TABLE 3. (cont'd) 



among sites, exposure periods, and years (Fig. 9). 

 At WP, FI, BP and GN, wood-loss was greatest 

 in the May-Nov exposure period (up to 95%) 

 and greater at GN and WP ( > 60%) than at BP 

 and FI (<40%). At the effluent sites (EB and 

 ES), considerable wood-loss occurred in both 

 Aug-Feb and May-Nov exposure periods during 

 3-unit operation. At all sites, wood-loss was low 

 during the Feb-Aug exposure period; in the Nov- 

 May period, wood-loss was very low at the 

 effluent sites, and zero at the ambient sites. The 

 disproportionately low levels of wood-loss (rela- 

 tive to Teredo abundance) in Feb-Aug are ex- 

 plained by shipworm size; they are young and 

 small, i.e., recently settled. Similarly, high densities 



of Teredo juveniles in Feb-Aug have little effect 

 on wood-loss. 



Interactions Between Fouling and 

 Wood-boring Communities 



Analysis of relationships among components 

 of the communities that develop on and in the 

 exposure panels show that densities of shipworms 

 are negatively correlated with the abundance of 

 foulcrs. In some cases, the effect of foulers on 

 woodborers is direct, e.g., high densities of bar- 

 nacles on a panel reduce the amount of space 

 available to settling Teredo larvae (Fig. 10). In 



Exposure Panel Program 



239 



