FISHERY BULLETIN: VOL. 71. NO. 2 



peake Bay, some as far as 111 km offshore, 

 but most from 22 to 83 km offshore over depths 

 of 31 to 57 m. Although the distribution of 

 larvae was continuous, distinct concentrations 

 occurred off Martha's Vineyard, off Long Island 

 and northern New Jersey, and off Delaware 

 Bay (Figure 4). By November, the distribution 

 of larvae had spread throughout the survey 

 area, apparently with a center of concentration 

 56 km off New Jersey, where water depths 

 ranged from 22 to 53 m (Figure 5). 



In December (1965), we found concentra- 

 tions of larv'ae off New Jersey and North 

 Carolina. The area of greatest abundance 

 was 37 to 83 km off the New Jersey coast, 

 at about the same location where we found 

 larvae most abundant during the November 

 (1966) cruise (Figure 6). By the end of Jan- 

 uary, the number of larvae and the area of 

 their distribution had diminished, most of them 

 being south of Cape Hatteras (Figure 7). In 

 April, we found larvae only in the southern 

 extreme of the survey area (Figure 8). In 

 May, we caught seven larvae which probably 

 represented remnants of late spawning off 

 the outer banks of North Carolina, since we 

 found no more during the next two cruises. 



The seasonal progression of spawning from 

 north to south, evident from the distribution 

 of eggs and larvae, was further substantiated 

 by the progressively smaller larvae that were 

 caught as we sampled southward on late fall 

 and winter cruises. In September, the newly 

 spawned larvae were confined to a small area 

 off western Long Island and northern New 

 Jersey. By October, larvae were distributed 

 over almost the entire northern half of the 

 survey area. In November, when they were 

 spread throughout the survey area, those south 

 of Delaware Bay were smaller than those north 

 of the Bay. In December (1965), larvae gen- 

 erally were largest north of Delaware Bay, 

 and progressively smaller at more southerly 

 stations, the smallest occurring south of Cape 

 Hatteras. Those south of Cape Hatteras in 

 February were small and newly hatched, while 

 most of those to the north had started to meta- 

 morphose. By April, when larvae were found 

 only south of Cape Hatteras, most had started 

 to metamorphose (Appendix Table 1). 



THE RELATION OF SPAWNING TO 

 WATER TEMPERATURES 



Spawning occurred principally within a 

 temperature range of 7°C during the year of 

 our survey. Over the whole season, we caught 

 77% of the eggs where bottom temperatures 

 were between 12° and 19 °C. This percentage 

 would probably be higher if some dispersion 

 by coastal circulation were taken into account. 

 Miller (1952)-' found surface water drifting 

 from 6 to 37 km/day within the survey area. 

 A minimal drift of 9 km daily would be suffi- 

 cient to place the origin of 98% of the eggs 

 we caught in bottom waters between 12° and 

 19 °C. There was no evidence that salinity 

 had any effect on the distribution of eggs or 

 larvae. 



At the beginning of the season, in September, 

 the summer thermocline remained intact. Water 

 temperatures at the surface and bottom dif- 

 fered by as much as 14.6 °C. The greatest 

 concentration of eggs was located off Long 

 Island, shoreward of the cold mass of bottom 

 water that persists during the summer months 

 from New York to as far south as Chesapeake 

 Bay (Bigelow, 1933). Where eggs were most 

 abundant at the surface, bottom temperatures 

 were between 18° and 19 °C (Figure 9). The 

 few eggs caught seaward of the cold bottom 

 water might have been spawned by a group 

 of fish that either had migrated from northerly 

 waters around the outer edge of the cold 

 bottom water or by a group that remained 

 in deep water throughout the year. By October, 

 the thermocline was less pronounced than in 

 September, and most of the eggs occurred 

 over bottom temperatures between 13° and 

 17°C (Figure 9). As in September, the seaward 

 distribution of eggs appeared restricted by the 

 cold mass of bottom water which remained 

 intact off Long Island and New Jersey. It 

 seems certain, therefore, that the inshore edge 

 of the cold water delimited the seaward 

 extent of the fall migration of spawning fish. 



^ Miller. A. R. 1952. A pattern of surface coastal 

 circulation inferred from surface salinity-temperature 

 data and drift bottle recoveries. Woods Hole Oceanogr. 

 Inst. Ref. No. 52-58, 14 p. (Unpubl. manuscr.) 



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