Hood and Johnson; Life history of Pagrus pagrus 



727 



"D 



zone. A second independent reading of the 

 subsample by both readers resulted in a 

 higher agreement rate of 86% and indicated 

 that both readers were consistently identi- 

 fying the same features as opaque zones. Of 

 877 sectioned otoliths examined, 852 (97%) 

 could be assigned ages. Of the otoliths that 

 could be aged, measurements for marginal- 

 increment analyses could not be made for 

 40 (4.6%) because of broken or occluded 

 areas along the otolith radius. 



Analyses of marginal-increment data for 

 fish ages 2-10 yr suggested that opaque 

 zones were formed once a year during the 

 late spring to early summer (Fig. 3 ). Because 

 of small sample sizes, we pooled marginal- 

 increment data for ages 8 to 10. During the 

 spring and early summer, the widest incre- 

 ments (ring formation was imminent) and 

 the narrowest increments (ring formation 

 was just completed) were present, indicat- 

 ing that rings were being formed during 

 this period. In addition, monthly median 

 marginal increments for ages 2-10 had a 

 consistent yearly pattern of high median 

 values from October to April and low values 

 from June to August (Fig. 3). 



Ages ranged from 1 to 17 years and most 

 fish (839'f) were between ages 3 and 8. No 

 females older than 10 years were observed. 

 Initial growth of red porgy was rapid, and fish attained a 

 mean length of 260 mm during their second year (age 1; 

 Table 4 ). Subsequent increases in length, however, were low 



50  



<2 50 100 150 200 250 300 350 400 450 500 550 600 

 o 



0) 



^ '°° 1 Commercial 



n = 276 



tt^ 



50 100 150 200 250 300 350 400 450 500 550 600 



Total length (mm) 



Figure 2 



Total lengths of red porgy from the eastern Gulf of Mexico by sampling 

 source. 



(<40 mm/yr). Average lengths at age were not significantly 

 different between males and females (^874i=l-5, P=0.155) 

 or between sampling sources (Fgg, 7=0.96, P=0.462). The 



