PEARCY niSTRIRl'TION AND ABUNDANCE OF SMALL FLATFLSHES 



FiGL'RE 3. — Variations in the total num- 

 bers of fishes caught at each of the seven 

 stations, 1968-71. The two tows at each 

 station for each samphng period were av- 

 eraged. 



OCT 



1968 



MAY AUG 

 1970 



The amount of variability explained by the re- 

 gression {R'^) of all effects on catches ranged from 

 0.16 to 0.51 (Table 4). Values were larger for the 

 analysis based on catches per square meter than 

 catches per tow, except for slender sole. These low 

 values indicate that most of the variability was 

 not accounted for by the variables of sediment, 

 depth, year, and season. Large residual mean 

 squares indicate that sampling variability as- 

 sociated with catches at individual stations is ap- 

 preciable. Oviatt and Nixon (1973) completed a 

 multiple regression analysis of biomass and num- 

 bers of benthic fishes in Narragansett Bay, R.I., 

 with 14 environmental variables. Depth and sed- 

 iment organic content contributed significantly to 

 the regression for total fish numbers and fish 

 biomass. But an R^ of only 0.21 was found. In both 

 of these studies, only a small fraction of the total 

 variability was explained by the environmental 

 factors included. 



Size-Frequency Distributions 



Differences in length-frequency distributions 

 were sometimes obvious among the stations lo- 

 cated at different depths or sediment types. For 

 example, the main length mode of rex sole at the 

 100- and 102-m stations was 125 mm, but at 190- 



and 195-m depth there was a distinct bimodal dis- 

 tribution with peaks at 45 and 215 mm (Figure 4). 

 These differences imply that young-of-the-year 



10 



U 

 F,20 



10 



ff£X SOLE 

 100- 102 m 

 n=t004 



— 1 1 r 1 1 — 



50 100 150 200 250 



STANDARD LENGTH (mm) 



300 



FIGURE 4.— Length-frequency data for rex sole at 100-102 m 

 stations (above) and 190-195 m stations (below). 



637 



