534 



Fishery Bulletin 90(3). 1992 



Figure 4 



Validation of daily deposition of otolith increments 

 in Taidoga onitis, comparing the number of incre- 

 ments outside a tetracycline-induced mark with the 

 number of days since marking. Numbers above data 

 points are numbers of fish tested; error bars are 

 SD's. Resulting regression line does not deviate 

 significantly (P>0.05) from a line of one-to-one 

 correspondence. 



Postrostrum 



700 

 600 

 500 - 

 400 

 300 

 200 - 

 100 

 



Antirostrum 



AR = -1 1 1.9 + 80. 6*SQRT(SL) 

 r^ = 0.94 



75 



800 

 700 

 600 - 

 500 

 400 

 300 

 200 

 100 - 

 



Rostrum 



-154.7-t-95.4.SQRT(SL) 



r = 0.92 



25 50 75 



Standard length 

 Figure 5 



Regressions comparing otolith radial measurements (see Fig. 3) with standard length 

 of juvenile Tautoga onitis. Displayed curves fit the square-root equations derived in regres- 

 sion analysis. 



radius measurements with standard length demonstrated 

 a strong correspondence for all three radii (Fig. 5). For 

 all three cases, a square-root equation provided the best 



fit. 



Settlement marks and larval 

 stage duration 



An obvious transition in the ap- 

 pearance of increments occurred 

 in the sagittae (Fig. 3). Inner in- 

 crements were generally more 

 distinct because they were higher 

 in contrast, darker in appear- 

 ance, and more circular than in- 

 crements outside the transitional 

 area. In the sagittal plane, outer 

 increments diverged in morphol- 

 ogy, with increased deposition 

 along the eventual axes of ros- 

 trum, postrostrum, and antiros- 

 trum. Sagittae of larval tautog 

 (n 5) were comprised of only the 

 darker, inner increments. Thus, 

 we believe this transition in in- 

 crement contrast and shape 

 takes place at or near the time of 

 settlement, when the individual 

 has completed transformation 

 and moved from a planktonic to 

 epibenthic lifestyle. Settlement 

 marks are a common feature of 

 labrid otoliths, allowing ready 

 distinction of larval and juvenile 

 increments (Victor 1986). 



The total number of incre- 

 ments (separated into larval and 

 juvenile stages) was counted for 

 37 individuals collected in the 

 Great Bay and Little Egg Har- 

 bor sampling. The number of in- 

 crements deposited during the 



25 



