686 



Fishery Bulletin 93(4). 1995 



9). Small juveniles (<10 cm TL) show a similar dis- 

 tributional pattern, although they tend to be more 

 abundant in shallower depths. Few have been col- 

 lected in the Gulf of Maine, but they were distrib- 

 uted over most of Georges Bank, especially in the 

 central portion. They were found closer to shore in 

 the Middle Atlantic Bight than on Georges Bank. 

 Small juveniles (<10 cm TL) were found in 4-82 m in 

 Massachusetts nearshore waters, but their average 

 capture depth was 23 m. In New Jersey nearshore 

 waters (5-27 m), larger juveniles and adults were 



Juvenile Wmdowpane 

 SPRING and FALL 

 2-10cmTolal Length 

 NMFS Bottom Trawl Surveys 1 982-1 991 h|36° 



W«s 



Figure 9 



Occurrence of two size classes of windowpane, Scoph- 

 thalmus aquosus, from spring and fall NMFS groundfish 

 surveys during 1982-91. 



abundant during all months, but small juveniles (<10 

 cm TL) were rare (Fig. 11). 



The seasonal patterns of abundance of window- 

 pane, based on NMFS bottom trawl survey catches, 

 varied markedly on the continental shelf (Table 4). 

 Fall catches offish <10 cm TL in subareas 1-5 aver- 

 aged <0.01 individuals per tow, 0.22 per tow in sub- 

 area 6, and 6.24 per tow in subarea 7. Spring catches 

 of these fish ranged from 0.07 to 0.46 fish per tow 

 across all subareas, with the highest catches in sub- 

 areas 2 and 3, which were 30 to 50 times higher than 

 those in the fall. In contrast to catches offish <10 cm 

 TL, catches offish 11-20 cm TL showed little variation 

 across subareas in the fall (0.72-1.82 fish/tow), whereas 

 spring catches were low in subareas 1 and 2 (0.09 fish/ 

 tow) and high in subareas 5 and 6 ( 1. 15-1.25 fish/tow). 

 In general, adult fish (>20 cm TL) catches were consis- 

 tently low in subarea 1, increased along the coast in 

 subareas 2-6, and peaked in subarea 7. This pattern 

 of adult catches differed for fish 21-30 cm TL in the 

 spring, when the peak catches occurred in subarea 3. 



The NMFS and Massachusetts fall and spring bot- 

 tom trawl surveys were analyzed to determine 

 whether the abundance of small juvenile window- 

 pane reflects the areal patterns in larval distribu- 

 tion and abundance mentioned above. NMFS sta- 

 tions, for spring and fall combined, at which win- 

 dowpane ( 11-48 cm TL) were captured are shown in 

 Figure 9A, and stations that contained juveniles 

 (<10 cm TL) are shown in Figure 9B. Although adults 

 occur in the northern Gulf of Maine, no juveniles were 

 collected there. The spatial patterns of abundance 

 for juveniles on the continental shelf coincide with 

 the patterns of abundance for larvae (see Figs. 3 and 

 9B). The inverse relationship of catches of juveniles 

 in the fall with larval mortality (r=-0.99, P<0.05 ) seems 

 to support the conclusion that mortality is controlling 

 recruitment; however, spring catches show no such re- 

 lationship (r=0.12, P<0.93). To test the possibility that 

 juveniles migrate to an area nearshore (<10 m depths) 

 or to estuarine habitats in the southern part of the sur- 

 vey area in the fall and were not sampled by the trawl 

 gear, we calculated the weighted mean capture depths 

 in each subarea for five size classes (Table 4). Small 

 juveniles (<10 cm TL) were captured at only 4 of 779 

 stations in subareas 1-4 in the fall at depths of 10-24 

 m. Larger juveniles (11-20 cm TL) were more abun- 

 dant and were captured at weighted mean depths 17— 

 19 m. Adults (21-30 cm TL) were found in slightly 

 deeper water (means= 22-27 m) and adults >30 cm TL 

 were captured at only 12 stations in mean depths from 

 14 to 38 m. Weighted mean depths of capture within 

 each subarea differed little between fall ( 10—38 m) and 

 spring (15-47 m) surveys or between size classes, al- 

 though a weak trend of increasing depth with size was 



