50 



40 



30 - 



20 



10 - 



81 



Figure 14. Percentage of impinged M. tomcod caught in each year since 

 October 1976. Counts were corrected for variations in 

 cooling-water flow rates. 



Modeling of tomcod abundance in the trawl and impingement programs 

 using harmonic regression techniques was moderately successful. Cycles 

 of 6- and 12-mo duration were common to both program models; JC and IN 

 trawl models also had 3- and 4-mo harmonic components (Table 9) . Model 

 R^ values ranged from 0,71 to 0.77 for trawl and impingement data. 

 P'orecast errors from trawl and impingement models were low except at TT 

 (161.2%). Examination of data from TT revealed that some 1983 catches 

 were below the 95% confidence limits during the predicted peak (Fig. 

 15) . Catch data from other stations and impingement data were within 

 the 95% confidence limits except for Unit 2 impingement where recent 

 estimates have increased relative to historical data (Fig. 15) . 



28 



