Starting in 1972, impinged organisms were collected over 24-h, 

 identified to species and counted daily. In March 1977 the counting 

 frequency was reduced to three 24-h samples per week. 



From January 1973 to April 1975, species length information was 

 recorded by length categories. However, this practice did not provide 

 accurate descriptions of the sizes of the various species impinged. 

 Length measurements were reins tituted in May 1975 (Table 1) . Lengths 

 were also recorded prior to 1973. 



Beginning in 1979-30, monthly impingement estimates were based on actual 

 counts (3 days/week) extrapolated using a volumetric ratio. Previously, counts 

 were multiplied by a real time to sample time ratio. 



Research directed towards improving our understanding of the factors 

 which influence impingement, and ultimately to reduce losses of fish due 

 to impingement, began in 1973. These special research projects, involved 

 cooling water flow, fish deterrent devices, impingement survival and 

 sluiceways. 



Routine impingement monitoring at Millstone together with the 

 numerous special studies, have provided quantitative data characterizing 

 impingement at the site. Adjustments to the field sampling aspects of 

 the program have been made without significant loss of information. 



Reductions in impingement mortalities and reductions in sampling 

 effort will result when a sluiceway is installed at Unit 1. Further 

 reductions in impingement sample effort of up to 40% are feasible at 

 Unit 2 while maintaining the current level of precision. 



