Intake sampling station was eliminated because low Intake flow velocities 

 resulted in poor flow meter response and net avoidance by zooplankton 

 and ichthyoplankton. The Quarry Cut station was eliminated as it was 

 not representative for entrainment estimates since quarry residence time 

 might allow organisms to settle out. The Discharge station was selected 

 for entrainment sampling because flow velocities were sufficiently fast 

 to eliminate problems of poor flow meter response and net avoidance. 

 Using an estimated variance formula, the degree of precision of the 

 sample mean for estimating the population mean was established, for 

 various confidence levels. The present sampling scheme was chosen since 

 it would provide a larval winter flounder sample mean within 40% ( « = 

 0.05) of the population mean with a practical sampling effort. 



The Discharge sampling location and collection method was changed 

 by NAI from the previous WHOI study (NUSCo 1976). Comparison of the 

 WHOI and NAI sampling techniques were made in September 1975. During 

 the month a total of 144 samples were taken by simultaneous collections 

 with both techniques. A comparison of the data using analysis of variance 

 and paired t-tests determined that WHOI and NAI sampling techniques at 

 the Discharge did not differ significantly ( = = 0.05) in their estimates 

 of fish larval or egg abundance. Thus, justification for directly 

 comparing Discharge data from the earlier WHOI and ongoing program was 

 established. 



An evaluation in 1978 concluded that the present entrainment sampling 

 effort permits detection ( <* = .10, 1-3 = 0.80) of a difference in 

 (log.. n transformed) mean annual densities for larval winter flounder and 

 anchovies of about 15% and 20%, respectively. This level of detectability 

 was achievable in part because the sampling program was evenly distributed 

 over tidal stages and day-night periods. 



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