Although we caught the most larvae in June, spawning 

 apparently had peaked about the end of April or the 

 beginning of May, as larvae <4 mm were most abundant 

 during the May cruise. No larvae were caught after 

 mid-September (Table 14). Our findings agree closely with 

 those of Royce et al. (1959). They estimated that 90% of the 

 yellowtail flounder landed in New Bedford, Mass., in 1943 

 spawned between 12 April and 26 June, with heaviest 

 spawning from 4 May to 4 June. 



P$eudopleuronectei amertcanuf (Walbaum), winter 

 flounder. — Winter flounder have been captured from as far 

 north as Labrador to as far south as Georgia, but they 

 seldom range north of Newfoundland or south of Chesapeake 

 Bay, where they occur from the inner reaches of the littoral 

 zone to depths of 128 m. Throughout its range, the species is 

 evidently composed of local independent populations, 

 perhaps the most notable being that group of exceptionally 

 large fish found on Georges Bank (Bigelow and Schroeder 

 1953). Larvae were described by Sullivan (1915), Perlmut- 

 ter (1939), and Bigelow and Schroeder (1953). 



Winter flounder are considered one of our least migratory 

 fish. A separate population seems to inhabit its own river 

 system along the northern half of the Middle Atlantic Bight, 

 where adults move but a few miles offshore to deep cool 

 water during the summer and return to the shallow waters 

 of their respective home bays or rivers for the winter 

 (Perlmutter 1947). Young-of-the-year remain inshore. 

 Spawning occurs in the estuaries during winter and early 

 spring. Eggs are demersal. Although the larvae are 

 pelagic, they become strongly bottom oriented even before 

 completion of metamorphosis, which occurs at about 8 mm 

 (Pearcy 1962). 



We caught larvae during the three spring cruises mostly 

 nearshore, but some midway out on the shelf over depths of 

 55 m. In AprU, when they were most abundant, their 

 distribution was continuous from Cape Cod to Chesapeake 

 Bay. There were concentrations of larvae off the northern 

 New Jersey coast, and from Delaware Bay southward to 

 Maryland over depths less than 20 m (Fig. 61). Both 

 concentrations were near the mouths of estuaries, and the 

 tide was ebbing when we sampled. Judging from the tidal 

 phase at the time, the known spawning habits of winter 

 flounder, and information from Pearcy (1962), who reported 

 that currents flush 3% of the winter flounder population per 

 day from the upper Mystic River, we assumed that most of 

 the winter flounder larvae collected during the three spring 

 cruises originated in estuaries and were subsequently 

 carried seaward by currents. Using incubation times and 

 growth rates reported by Bigelow and Schroeder (1953), we 

 calculated that most of those caught in AprU had been 

 spawned during the latter half of March (Table 15). 



In May, the distribution of larvae was again continuous 

 from Cape Cod to Chesapeake Bay, but the center of 

 abundance occurred off southern New England, or farther 

 north than in April (Fig. 62). Larvae occurred only off Cape 

 Cod in June (Fig. 63). We assumed from their absence 

 farther south that spawning had ended in the adjacent 

 estuaries. 



The characteristic south-to-north progression in spawning 

 that we found prevalent in offshore spring spawners is 

 apparent in our collections of winter flounder larvae. Since 

 winter flounder populations in the bight are isolated when 

 spawning, each having its own home river system, the 

 northward progression of spawning that is evident in our 



Figure 60. —Distribution and relative abundance of yellowtafl 

 flounder, Limaiidaferruginea, larvae coDected during 1965-66 

 survey. 



58 



