684 



Fishery Bulletin 93(4), 1995 



tions contained these larvae. In subareas 5 and 6, 27 

 of 2,461 stations had larvae >8 mm long. Larvae >13 

 mm were captured in only 10 of 5,743 stations in 

 subareas 1-6. In contrast, in subarea 7, 89 of 1,473 

 stations had >8 mm larvae and 31 stations had >13 

 mm larvae. In an attempt to interpret the trend of 

 increasing maximum lengths from south to north, 

 the abundances at length and mortality estimates 

 for larvae <20 mm, grouped by subarea, were calcu- 

 lated (Table 3). The maximum larval length of catches 

 >0.1/100m 2 and mortality for each subarea is shown 

 in Figure 7. If avoidance of the sampling gear occurs 

 because of settlement within a narrow size interval 

 (e.g. 1-3 mm), then the catches should show a pre- 

 cipitous decrease in abundance at settlement. No 

 such abrupt decrease can be seen in the data (see 

 Tables 2 and 3); thus the declines in abundance with 

 size are due to other causes. Alternatively, if we as- 

 sume that decreases in larval abundance are due to 

 mortality, then the percentage of mortality per mm 

 of growth is highest in subarea 1 (63%), intermedi- 

 ate in subareas 2-5 (range 48-56%), declines to 38% 

 in subarea 6, and is lowest in subarea 7 (30%). Esti- 

 mated mortalities are inversely related to the maxi- 

 mum lengths of captured fish and decrease from 

 south to north along the coast (Fig. 7). The relatively 

 high mortality indicated for larvae in subareas 1—5 

 could explain the truncated larval length frequen- 

 cies seen there, particularly during the months of 

 July-October (Table 2). 



Larger larvae in the Middle Atlantic Bight sub- 

 areas may move into or are more abundant in shal- 

 low nearshore areas of the continental shelf and es- 

 tuaries and thus may not be available to the collect- 



Subareas 



Figure 7 



Length-dependent mortality rates and the maxi- 

 mum larval lengths of catches >0. 1/100 m 2 by sub- 

 area from NMFS MARMAP sampling of window- 

 pane, Scophthahnus aquosus, off the northeast 

 United States. 



ing gear. Typically, NMFS/MARMAP sampling is not 

 undertaken in estuaries and is limited to depths 

 >10 m on the continental shelf. During the MARMAP 

 study, approximately 13% of all tows were taken in 

 depths <20 m, whereas only 0.3% were taken in wa- 

 ter depths <10 m. In the vicinity of Little Egg Inlet, 

 New Jersey, larvae were abundant on the inner con- 

 tinental shelf and in the estuary (Fig. 8). Eggs and 

 larvae were least abundant in the Mullica River, more 

 abundant farther down the estuary in Great Bay and 

 at Little Egg Inlet, and most abundant on the adja- 

 cent portion of the inner continental shelf (Fig. 8). 

 Eggs and larvae were abundant in the estuary dur- 

 ing spring, but both were most abundant on the con- 

 tinental shelf during the fall. 



Juvenile and adult distribution and 

 abundance 



Windowpane are distributed over much of the conti- 

 nental shelf, as well as in estuaries in the Middle 

 Atlantic Bight. Large juvenile and adult windowpane 

 (>10 cm TL) were collected from the western portion 

 of the Gulf of Maine to Cape Hatteras, North Caro- 

 lina (Figs. 9, 10), in depths from 5 to 207 m. In the 

 Gulf of Maine, there were few fish of this size col- 

 lected from coastal Maine, but they were more abun- 

 dant off the coast of Massachusetts, subarea 6 (Fig. 



Eggs 



□ Site 1 



 Site 2 



SS Little Egg Inlet 



I I Great Bay 



 Mullica River 



0^ 

 250 



Larvae 



1 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 



Month 



Figure 8 



Monthly patterns of distribution and abundance of win- 

 dowpane, Scophthahnus aquosus, eggs and larvae from the 

 vicinity of Little Egg Inlet, New Jersey, during 1972-75, 

 as modified from Milstein and Thomas ( 1977). See Figure 

 2 for sampling locations. 



