690 



Fishery Bulletin 93(4), 1995 



ED ESTUARY 

  OCEAN 



FEBRUARY 



E 

 3 



DECEMBER 

 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 



Length (cm) 

 Figure 12 



Length-frequency distribution of windowpane, Scoph- 

 thalmus aquosus, by month, based on collections in the 

 estuarine and ocean in the vicinity of Little Egg Inlet, New 

 Jersey, as modified from Milstein and Thomas ( 1977). Es- 

 tuarine samples represent all samples not taken in the 

 ocean. Station locations are indicated in Figure 2. 



ing at the southern portion of the Middle Atlantic 

 Bight (south of Chesapeake Bay) in April or May. 

 Peak spawning progresses northward as waters 

 warm, and spawning reaches Georges Bank by July 

 and August. As waters cool during fall, spawning moves 

 south to off New York and New Jersey, and by Novem- 

 ber spawning is again centered in the southern part of 

 the Middle Atlantic Bight. The split spawning season 

 pattern has also been verified for New Jersey in the 

 vicinity of Little Egg Inlet (Fig. 8) and farther south at 

 Hereford's Inlet, New Jersey (Keirans, 1977). 



Seasonally varying temperatures clearly influ- 

 enced the timing of spawning. We found maximum 

 numbers of small larvae at temperatures between 

 16 and 19°C in subareas 1-5 (Fig. 5), except on 

 Georges Bank where the maximum larval abundance 



occurred at temperatures (13-16°C), approximately 

 those reported by Smith et al. (1975). They found 

 70% of small larvae over bottom water temperatures 

 between 8.5 and 13.5°C between Cape Hatteras and 

 Block Island (subareas 1-5). It appears that spawn- 

 ing during the single year (1965-66) of their study 

 occurred at temperatures around 6°C, colder than 

 our findings from a data set that was more exten- 

 sive both temporally and latitudinally. 



Reports of eggs from Great Bay (Fig. 8) and 

 Hereford's Inlet (Keirans, 1977), New Jersey, Chesa- 

 peake Bay, Virginia (Olney, 1983; Olney and Boehlert, 

 1988), Long Island Sound (Wheatland, 1956; 

 Richards, 1959; Perlmutter, 1939), Great South Bay 

 on Long Island (Monteleone, 1992), and Narragansett 

 Bay, Rhode Island (Herman, 1963; Bourne and 

 Govoni, 1988), strongly suggest that spawning oc- 

 curs in the lower portions of estuaries in the Middle 

 Atlantic Bight. These sources imply that the influ- 

 ence of estuaries on the early life history of window- 

 pane may be important in the Middle Atlantic Bight. 



Age and growth 



Growth after settlement was markedly different be- 

 tween the spring- and fall-spawned cohorts in New 

 Jersey waters. The spring-spawned cohort grew 

 quickly during the summer and reached sizes of 11— 

 19 cm TL in September, approximately 4 months 

 later (Fig. 12). The fall-spawned cohort, exposed to 

 winter temperatures soon after settlement, appar- 

 ently did not grow during the winter and grew to 

 only 4-8 cm TL six months later in March (Fig. 12). 

 Thus, the timing of spawning (spring vs. fall) influ- 

 ences growth rates and the age and size composition 

 of young of the year. 



Reported estimates of growth from scale annuli, 

 regardless of spawning season, were quite different. 

 In studies for Long Island Sound and North Caro- 

 lina age-2+ fish averaged only 11.7 cm TL (Moore, 

 1947) and 10-13 cm TL (Shelton, 1979), respectively. 

 Sizes at age 1 reported for our study area were 18 

 cm TL (Grosslein and Azarovitz, 1982) and 14.5 cm 

 TL (Thorpe, 1991) and were more consistent with 

 our results, although the season of spawning could 

 easily affect size at age. Clearly, more detailed stud- 

 ies of spawning times and their effects on age com- 

 position and growth of juveniles are needed before 

 we can completely understand the population dynam- 

 ics of this species. 



Nursery areas 



In general, the distribution of larvae and juveniles 

 on the continental shelf coincided and showed that 



