for total larvae and lowest for the anchovies (the probability of detecting 

 a difference in means of 0.25 was 0.97 for total larvae and 0.45 for the 

 anchovies) . The highest power for total larvae corresponds to the 

 greatest number of samples. The lowest power for anchovies indicated 

 greater variability in sample density since anchovies were the second 

 most frequently sampled taxon. 



For each of the six taxa, the power curves for detecting differences 

 between yearly means at the Discharge were almost identical for the six 

 paired comparisons of years 197 6 through 1979. This similarity in power 

 curves irrespective of which years were compared indicated a similar 

 probability of detecting a specified change in mean density for any two 

 years. The probability of detecting a difference of 0.15 in mean density 

 from log.. „ transformed data, between 1978 and 197 9 for total larvae, 

 sand lance, winter flounder, cunner, anchovies and tautog was 0.97, 

 .0.76, 0.61, 0.52, 0.47 and 0.38, respectively. Caution should be used 

 when comparing taxa since the size of the population mean will determine 

 the ecological importance of a specific difference between yearly means. 



Proposed Changes to the Entrainment Program 



As the result of a 1981 evaluation additional modifications to the 

 entrainment ichthyoplankton program (E.T.S. Change Request #81-2, 1981) 

 have been recommended and will be implemented pending NRC approval. 

 These recommendations include discontinuing identification of fish eggs 

 from entrainment samples collected during October through March and 

 changing the entrainment sampling frequency to one day and one night 

 sample on each of four days weekly. 



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