A comparison of the spatial distribution of each developmental stage in 1983 through 1985 was based 

 on the cumulative abundance of weekly mean densities at each station (Fig. 14). As previously stated, 

 Stage 1 larvae were collected almost exclusively in the river and their low abundance in 1983 compared 

 to Stage 2 larvae was the reason for conducting net extrusion studies in 1984 and 1985. Their annual 

 spatial distribution varied with the greatest numbers collected at stations B and C in 1984 and at station 

 A in 1985. A similar pattern was found for Stage 2 larvae in 1984 and 1985. The previously mentioned 

 high mortality from Stage 2 or 3 in 1985 was apparent at all river stations. Stage 3 and 4 larvae were 

 primarily collected in the lower portion of the river at C and at Niantic Bay stations, but rarely at A. The 

 decline in larval abundance since 1983 in the bay (Fig. 13) was reflected in decreasing frequency of Stage 

 3 and 4 larvae at EN and NB. The decline in Stage 4 larvae in the river and bay (Table 22) from 1983 

 through 1985 was evident at stations B, C, EN, and NB. 



Time-based harmonic regression models were used to describe the fluctuations in abundance of larval 

 winter flounder at station EN (1976-85) and NB (1979-85). Both models had a seasonal component and 

 1-yr and 6-mo terms (Table 24). It was possible to correct for autocorrelation at station EN because the 

 data were evenly spaced in time. No long-term trends were present in either model. The models fitted 

 the data well with R^ values of 0.93 for EN and 0.91 for NB. The time-based models will be used as 

 base-line information on the abundance of larval winter flounder for a comparison to their abundance 

 during Unit 3 operation. 



Table 24. Summary of time-based regression models to describe the occurrence of 

 larval winter flounder at stations EN and NB. 



Station Model^ Model R^ 



i 



EN s {sin(l r) - cos(l K) - sin(6m) - cos(6wi)} -\- A/ + A2 - A3 - A8 0-93 



NB s {sin(l r) - cos(l r) - sm{6m) - cos(6m)} 0-9 1 



S = Season 



nY, nM = period in years or months 



An = autoregression coefficients 



73 



