In 1985 and 1986, a second estimate of wood-loss was obtained, based on weight. This measure 

 compared the pre-deployment weight of each panel with its weight after retrieval. Panels were dried at 

 80 °C for 96 h and weighed to the nearest 0. 1 g before deployment. After collection and panel processing, 

 each panel was soaked in 10% HCl for at least 48 h to dissolve calcium carbonate tubes secreted by 

 shipworms. Next, the panel was soaked for at least 48 h in two changes of fresh water to rinse the HCL 

 away before the panel was oven dried at 80 "C for 96 h. Panels were weighed to the nearest 0.1 g 

 immediately upon removal from the drying oven. 



DATA ANALYSIS 



The data represented in this report comprise five collection years prior to three-unit operation at 

 MNPS. The first set of panels was deployed in November 1978 and the last set of panels was collected 

 in May 1986. The collection years summarized in this report are: 1979 with three exposure periods, 1980 

 and 1981 with four exposure periods each, and more recently 1985 and 1986 with two exposure periods 

 each (Table 1). The monitoring of these panels was suspended from November 1981 to February 1985 

 (Appendix EP II, U.S. NRC, Docket Nos. 50-245 and 50-336, LS05-81-04-006, Exposure Panels) to 

 conduct special studies concerning the life histories of two shipworms. Teredo navalis and T. bartschi, in 

 relation to the mixing of effluent and ambient water at MNPS (report in preparation). These studies were 

 undertaken to acquire a better understanding of the limiting factors which restricted T. bartschi to the 

 Millstone Quarry. 



The four exposure periods in each collection year do not represent a continuum because each period 

 overlaps the next by three months. Therefore, all averages and other summary statistics were computed 

 by exposure period. Data reported as percentages of primary cover were the estimated proportions of 

 exposed wood surface found covered by the most common species of foulers. Since all the exposure 

 panels were of equal size, the percentages of cover were treated as regular (or additive) count-data rather 

 than as ratios. These data for fouling species were based on 197 cm of panel surface, while wood-loss 

 estimates were based on the entire volume of a panel, or 422 cm . 



