STUDIES ON THE STRIPED BASS OF THE ATLANTIC COAST 49 



Turning now to the two middle sets of length-frequencies in figure 32, those from 

 scale measurements from fish taken in northern and southern Chesapeake Bay in 

 February and March 1937, it is apparent that these are also from samples of the 

 dominant 1934 year-class at tbe time its members were just becoming 3 years old, and 

 when the third annulus was in the process of formation on the anterior margin of the 

 scale. Looking at the widths of the first two growth zones, it is immediately apparent 

 that the general distribution of the length frequencies and the peaks of the first 

 growth zones and the second growth zones are similar throughout. Furthermore, 

 they coincide almost exactly with the same growth zones of the scales from fish born 

 in the same year but collected at a later date in northern waters — see the top three sets 

 of curves in figure 32. It cannot be assumed, however, although it may well be true, 

 that these samples from Chesapeake Bay are from fish that were produced in that 

 region and had remained there, since it is known that this species often undertakes 

 coastal migrations after it becomes 2 years old. Thus these fish might have moved 

 into Chesapeake Bay in 1936, and might, therefore, not have had their origin in this 

 region. On this account, it is not possible to assert that the similarity in the widths of 

 the first growth zones and those of the second growth zones in the top five sets of 

 curves in figure 32 is proof that the dominant year-class of 1934 originated in Chesa- 

 peake Bay. These similarities do, however, suggest that this is so. 



Looking at the bottom set of curves in figure 32, those from scales from fish 

 taken in Currituck Sound, N. C, it is again apparent that the widths of the first 

 growth zones are much the same as those for all the other samples in this figure, 

 although they do tend to be slightly less. The widths of the second growth zones of 

 scales of the fish from this area, however, are strikingly different from any that precede 

 it in figure 32. Whereas the widths of the second growth zones of the scales from 

 fish from northern waters and from Chesapeake Bay in 1937 all range from approxi- 

 mately 0.5 mm. to or slightly over 2.0 mm. (with peaks at 1.0 mm.), the widths of 

 the second growth zones of scales from fish from Currituck Sound range from about 

 2.0 to 3.6 mm. (with a peak at 2.9 mm.). These second growth zones of the scales 

 from fish from Currituck Sound are labelled incomplete marginal zones in figure 32 

 because the second annuli, although in the process of formation on the anterior mnrgins 

 of the scales, were still indistinct. Therefore, the measurements of the marginal 

 zones are to all intents and purposes equivalent to what those on the second growth 

 zones would have, been had the second annuli been completely formed. It should 

 not be necessary to point out that if there were any differences from this factor, the 

 widths of the second growth zones would have been even greater. 



There is no doubt that these completely different, and exceptionally wide second 

 growth zones on the scales from fish from Currituck Sound are characteristic of the 

 bass born in that general region in 1935, for these scales were taken from fish that 

 were slightly less than 2 years old, and therefore had not undertaken any coastal 

 migration. Thus the wide second growth zones on scales from fish born in the genera] 

 Albemarle Sound region in 1935 give promise of being a means of distinguishing iisli 

 from this area from those born farther north. And since these wide growth zones are 

 so different from the other growth zones in figure 32, they provide added evidence 

 that the dominant 1934 year-class arose in the general latitude of Chesapeake Bay. 

 They also tend to show that those bass born in North Carolina do not contribute a 

 large proportion of the population that summers in northern waters. On the other 

 hand, the fish that make up the top five sets of curves in figure 32 were all born in 

 1934, while those that make up the bottom set of curves (Currituck Sound) were 

 bom in 1935; and it should be pointed out that the comparison of the widths of the 

 second growth zones of scales from fish born in different years may be fallacious. 

 Thus there is no evidence from the single sampling in Currituck Sound in 1937 as to 

 whether the wide second growth zone is truly a regional difference that occurs annu- 

 ally, or whether it was only a characteristic of the 1935 year-class. However, scale 

 measurements from samplings of bass of the same age — 2 years old in the spring of 

 1937— as those from Currituck Sound but taken in different areas, southern New 

 England and southern Chesapeake Bay, appear in figure 33. (Tbe length-frequency 

 curves of the scale measurements of the sample from Currituck Sound shown at 



