100 



• females 

 « transitional 



<700 



1 — r 



BOO 900 1000 1100 1200 



TOTAL LENGTH (mm) 



Figure 3. — Percent female gag by length class, 

 and occurrence of transitional gag. 



rings detected in the present study are annual in 

 nature. While the importance of adequate valida- 

 tion has been well documented (Beamish and 

 McFarlane 1983), it has become increasingly 

 clear that annulus formation in many species can 

 take place over an extended period, making it 

 difficult to pinpoint this event in time. Peak an- 

 nulus formation covered a 3-mo period for the 

 groupers Epinephelus drummondhayi (speckled 

 hind) and E. niveatus (snowy grouper) (Matheson 

 and Huntsman 1984). Thus, the May-August pe- 

 riod of peak ring formation for younger gag in the 

 present study is not unusually long. Reasons for 

 differences between ages <VIII and >IX in tim- 

 ing of peak annulus formation are not apparent. 

 However, that the differences are at least par- 

 tially based on sex is probable since the younger 



fish are predominately female while approxi- 

 mately 60% of the older group are male. A com- 

 parison strictly between sexes was not possible 

 since samples of males available for measure- 

 ment were obtained in only 5 months. 



The use of sectioned sagittae greatly enhanced 

 clarity among the higher age groups and allowed 

 for greater distinction between rings in compari- 

 son to whole otoliths. Beamish (1979) found that 

 sectioned otoliths of the Pacific hake, Merluccius 

 productus , gave a more accurate account of age, 

 especially when thick otoliths with poorly defined 

 annuli were encountered. This appears to be true 

 for the gag, as well. Twenty-two age groups were 

 distinguished in the present study, similar to the 

 21 age groups reported for the scamp (Matheson 

 et al. 1986), compared with previous reports of 13 

 age groups for the gag (McErlean 1963; Manooch 

 and Haimovici 1978). The nine groups not de- 

 tected previously do not represent just an in- 

 crease in the percentage of readable otoliths 

 (present study: 87%; McErlean 1963: 87%; 

 Manooch and Haimovici 1978: 79%). Rather, it 

 appears that additional annuli are present in the 

 otoliths of the larger size classes that were not 

 detected in previous studies using whole otoliths. 

 For instance, the oldest fish collected by Manooch 

 and Haimovici (1978) was age XIII and 1,201 mm 

 TL, longer than any gag aged in the present study 

 and 77 mm longer than the age XXII fish 

 (Table 1). 



Moe (1969) described the reproductive biology 

 of the red grouper, Epinephelus morio, and many 

 aspects of the development and sex succession 

 schedules are similar to those found in the gag. 



I00-, 



< 80- 

 UJ 



u. 



UJ 60- 

 tr. 



< 



z 



UJ 



u 



UJ 



a. 



40- 



20- 



GONAD CONDITION 

 O Oeveloping - running ripe 



• Post -spawned 



"T" 

 M 



n I 



M J 



MONTH 



Figure 4. — Maturity stages of female gag by month of capture, illustrating the late winter-early spring 



spawning season. 



651 



