was not available. The analysis was based on towtime and tidal stage 

 compared to volume estimates. It was determined that the volume estimates 

 from the four GO meter array were more accurate than the ERB estimates 

 since the GO array accounted for horizontal and vertical differences in 

 discharge flow. Dr. F. Bolen (pers. comm.) of the University of Connecticut, 

 a noted hydrology expert, indicated that such results would be expected 

 due to the configuration of the discharges, the water velocities, and 

 the net position. His judgement was that the four GO flowmeters would 

 more accurately characterize the flow through the plankton net. 



Detectability of Present Entrainment Program 



Absolute differences between ichthyoplankton population means that 

 would indicate a plant-related impact are not known. Therefore, in a 

 1980 evaluation (NUSCo 1980), power curves were constructed for a range 

 of hypothetical differences in means. Power curves for differences 

 between Station 5 (offshore) and the Discharge in 1979 and between pairs 

 of years from 197 6 through 1979 at the Discharge were calculated for 

 total larvae and five important local larval taxa (winter flounder, sand 

 lance, cunner, anchovies, and tautog) . The curves were based on a two- 

 tail test of 1 = 0.05 and the data were transformed by l°g-i to satisfy 

 the normal assumptions of parametric test used. 



Power curves for spatial differences between the Discharge and 

 Station 5 in 1979 were almost identical for winter flounder, sand lance, 

 cunner and tautog (probability of detecting a difference in means of 

 0.25 was 0.85) which indicated the same probability of detecting a 

 specified difference in densities of these species. The power of detecting 

 a specific difference in means for log _ transformed data was highest 



23 



