anchovy {Stolephoriis purpureus) and in showing 

 the daily nature of these lamellae. 



This paper reports on studies of the age and 

 growth of the Hawaiian endemic millet-seed 

 butterflyfish, Chaetodon miliaris Quoy and 

 Gaimard (Perciforms: Chaetodontidae), using this 

 approach. Butterflyfishes are exceptionally at- 

 tractive and are heavily exploited by the aquarium 

 industry in Hawaii. This study was initiated in 

 order to obtain information useful to state 

 regulatory agencies in the management of reef 

 fish stocks. 



DORSAL DOME 



NUCIEAR AREA 



EXCISURA 



ROSTRUM 



SULCUS 



Methods 



All fish were collected by spearing around the 

 island of Oahu, Hawaii, during 1974 and were 

 measured to the nearest millimeter standard 

 length (SL) while still fresh. Next, the otoliths 

 were extracted by means of a horizontal section 

 through the cranium above the eyes. Of the 

 three otoliths on each side, only the largest, the 

 sagitta, was studied. Figure 1 depicts a left sagitta 

 of a 94-mm C. miliaris viewed medially. After 

 both sagittae were removed, all membranes and 

 endolymph were carefully teased way under a 

 dissecting microscope. The otoliths were then 

 rinsed in water and placed in a 2% aqueous solution 

 of HCl for several minutes of etching. They were 



Figure l.-Schematic representation of the left sagitta of a 

 94-nim Chaetodon miliaris viewed medially. 



then rinsed again, thoroughly dried, and finally 

 mounted in depressions of glass slides where they 

 were immersed in euparal (an aromatic oil which 

 acts as a clearing agent) and covered with glass 

 cover slips. After clearing for 2 wk, the otoliths 

 were ready for reading. Otoliths were read from 

 the nucleus outward along their long axis with a 

 compound binocular microscope utilizing trans- 

 mitted light at a magnification of 400 x (Figure 2). 

 The rings in each sagitta were counted twice, 

 using a hand counter, and the average of the four 

 readings obtained from each specimen was used to 

 estimate the age of the fish in days. 



1^ 



¥vr^* • 



'& V H 



Figure 2.-Intemal ring structure of 

 the otolith of Chaetodon miliaris 

 specimen number 11. Not all the rings 

 are visible in this photograph. 





991 



