' SMITH: DISTRIBUTION OF SUMMER FLOUNDER 



(designated transect X) off the outer banks of 

 North Carolina. On our second cruise, inclement 

 weather forced us to omit four stations on the 

 northernmost transect, and an outflow of ice 

 from Delaware Bay prevented sampling at 

 the inboard station off Cape Henlopen. We 

 occupied all stations during cruises in April, 

 May, June, and August. In September, adverse 

 weather resulted in a 2-day interruption shortly 

 after we began sampling, and gear problems 

 required a second unscheduled port call soon 

 thereafter. Because of these delays, we re- 

 scheduled the cruise after completing only the 

 four northern transects. Although bad weather 

 also interrupted the final two cruises, we 

 occupied all stations. 



SAMPLING METHODS 



We used Gulf V high speed nets (Arnold, 

 1959) to collect plankton. These had 0.33-mm 

 Monel2 wire netting with 12 meshes/cm and a 

 mesh aperture of 0.52 mm. 



To assure reaching below the thermocline, 

 or that part of the water column encompassing 

 most pelagic eggs and larvae, we sampled to a 

 maximum depth of 33 m, using two Gulf V nets. 

 One net, hereafter referred to as net no. 1, 

 fished at 3-m depth intervals from surface to 

 15 m; the other, net no. 2, fished at 3-m depth 

 intervals from 18 to 33 m. We sampled at 

 each depth interval for 5 min. Tows lasted 30 

 min. In depths less than 33 m, we altered the 

 sampling pattern of net no. 2 by decreasing the 

 number of sampling depth intervals and increas- 

 ing the towing time at each interval to 10 or 

 to 15 min. Sampling depths for net no. 1 were 

 similarly adjusted in depths less than 15 m 

 (Figure 2). The RV Dolphin usually traversed 

 4.6 km/tow, traveling at a constant engine 

 speed. We preserved plankton samples in 5% 

 buffered Formalin. 



Catch per standard tow was used as a meas- 

 ure of relative abundance for eggs and larvae. 

 A standard tow consisted of one or both nets 

 fishing for 5 min at each of the six depth 

 intervals within its vertical sampling range 



- Reference to trade names does not imply endorse- 

 ment by the National Marine Fisheries Service, NOAA. 



(see Figure 2). The catches were adjusted to 

 equalize sampling effort at all depth levels 

 when either net was limited to sampling at 

 less than six intervals. For example, when 

 only three intervals were sampled during the 

 30-min tow, the catch was halved. When two 

 intervals were fished, it was reduced by two- 

 thirds. The adjusted catch of net no. 2 was added 

 to that of net no. 1 at stations where both 

 nets fished simultaneously. All catches of eggs 

 and larvae discussed herein are adjusted. 



We recorded vertical temperature and salinity 

 data at each station (Clark et al., 1969). Surface 

 temperature was measured with a stem ther- 

 mometer, subsurface temperature with a me- 

 chanical bathythermograph, and salinity with 

 an induction salinometer. Salinity data were 

 recorded at 5-m depth intervals to a maximum 

 depth of 40 m. 



Fish eggs and lai-vae were separated from 

 the plankton collections by microscopically exam- 

 ining aliquots of a sample placed in a gridded 

 Petri dish. Methods employed to check sorting 

 accuracy and measured plankton volumes are 

 described by Clark et al. (1969). 



Larvae on which the caudal rays had not 

 formed were measured from the tip of the 

 snout to the tip of the notochord. More de- 

 veloped specimens were measured from the tip 

 of the snout to the base of the median caudal 

 rays. Specimens larger than 9 mm were con- 

 sidered postlarvae because they were laterally 

 flattened. Marginal fin ray counts fell within 

 the adult range and migration of the right 

 eye was underway on specimens over 10 mm. 



THE SEASONAL DISTRIBUTION 

 OF EGGS 



We sampled during parts of two different 

 spawning seasons, for our survey started too 

 late in 1965 and ended too early in 1966 to 

 determine the beginning of the one season or 

 the end of the other. In spite of the possibility 

 of year-to-year variations in the onset and 

 duration of spawning, data for the 2 years 

 were combined and treated as a single complete 

 season. 



Although the summer flounder's spawning 



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