But the calculated and measured lengths agree remarkably (table 2 also fig. In the case of the comparisons of measured and calculated lengths (table 2), if the annuli represented winters a discrepancy between the averages would be expected for the fishes measured would be approximately an even number of years old (spawned in June and measured in July and August), while the winters represent points midway between birthdays. But the small number of circuli found points to May or June as the time of formation of the last annulus. If only 1 annulus was evident, there were 20. If the annuli represented winters, then in July and August the number between the periphery and the last annulus ought to be at least half the average number of circuli between any two adjacent annuli. Scales from 2nd winter (freshwater-age-2) fish with 2 evident annuli had a minimum of 10 and maximum of 20 circuli. That the annuli do not represent winters, as contended by the previously mentioned investigators, is verified by the observations on Cynoscion regalis as already noted. one annulus may be produced each year, but that it is not produced by retarded growth, nor does it consist of approximated circuli. Dotted line represents the expected curve of such a correlation if the annuli were groups of approximated circuli. i.-Showing number and distance apart of the circuli on a scale of the squeteague including two annuli.
The suppositions referred to are negatived by these observations, and it remains that Fig. In the third place, that annuli and circuli have nothing in common is proved beyond doubt by the fact that the former may cross the latter. Groups of tightly spaced circuli indicate a period of slower growth (also known as annuli), whereas widely spaced circuli indicate a period where the fish has grown more rapidly.
If each annulus represented a year and the circuli appeared at regular intervals of time, then the number of circuli could vary but little in each band. These events can be identified by changes in the relative spacing between the individual rings on the scale, called circuli.
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