52 
Fishery Bulletin 95(1 ), 1 997 
ing aggregation (doubtful as this may be), their con- 
tribution to the total reproductive output (of the ag- 
gregation), in relation to the small size of their tes- 
tes, would likely be extremely low. Therefore, from a 
management view point, the L f)0 estimates based on 
drumming muscle development were regarded as 
more useful than those based on gonad staging. 
According to Griffiths (in press, a), there was no 
difference between the growth rates of A. inodorus 
in the southeastern Cape and those in the southern 
Cape during 1990-91. The smaller sizes at maturity 
in the former region were therefore due to earlier ma- 
turity and not to slower growth. Female L 50 and total 
maturity are attained at about 1.3 and 3.5 yr in the 
southeastern Cape and at about 2.4 and 4.7 30" in the 
southern Cape. Male L 50 , based on testes staging and 
on drumming muscle development, was attained at <1 
yr and at 1 yr for silver kob in the southeastern Cape, 
and at <1 yr (testes staging) and at 1.5 yr (drumming 
muscle development) in the southern Cape. Total male 
maturity was attained at about 2.8 yr in the south- 
eastern Cape and at about 3.4 yr in the southern Cape. 
Spawning 
Gonadosomatic indices (Fig. 9) and gonad maturity 
indices (Fig. 10) for silver kob in the southeastern 
Cape showed that although some spawning occurred 
throughout the year, there was a clearly defined 
breeding season from August to December and that 
peak spawning occurred in spring (Sep-Nov). These 
results are in general agreement with those of Smale 
(1985) for Algoa Bay, but his spawning season ap- 
pears to have been “extended” by about one month, 
through the inclusion of A. japonicus, which spawns 
from October to January (Griffiths, in press, b) in 
the southeastern Cape. The low proportion of ripe 
and running (stage-6) females sampled during the 
spawning season (Fig. 10; and Smale, 1985) suggests 
that females feed less and are therefore less prone 
to capture (with hook and line) after oocyte hydra- 
tion. This inference is supported by a much higher 
proportion of stage-6 females in catches of silver kob 
caught by beach seines in False Bay than in catches 
made by using hook and line in four other localities 
