462 
Fishery Bulletin 95(3), 1997 
species in the Gulf of California is distinct from the 
Caribbean A. uulpes (Pfeiler, 1996). 
Most of the bonefish in our sample that were 
caught with hook-and-line gear were 500-700 mm 
long (80%) and 3-10 years old (86%; Crabtree et al., 
1996). If the length and age composition of our hook- 
1992 1993 1994 
Month 
Figure 4 
Monthly mean percent frequency of occurrence and standard er- 
rors of oocyte stages in bonefish, Albula vulpes, ovaries (n= 250) 
for 1992-94. * = primary growth stage oocytes, 0 = cortical alveo- 
lar oocytes, and □ = vitellogenic oocytes. 
and-line sample reflects that of the fishery, as sug- 
gested by Crabtree et al. (1996), then most of the 
fish caught in the fishery are longer than our esti- 
mate of length at 50% maturity and older than our 
estimate of age at 50% maturity. The current 390- 
mm-FL (457-mm-TL) legal minimum fish length 
imposed upon the fishery is less than our esti- 
mate of the length at 50% maturity for males 
(418 mm FL) and females (488 mm FL). 
Crabtree et al. (1996) found little evidence of 
fishing mortality in the Florida Keys because 
most bonefish caught by recreational anglers 
are released; thus, the population would prob- 
ably be insensitive to changes in the legal mini- 
mum fish length. 
The presence of PAS-positive melanoma- 
crophage centers was related to gonadal activ- 
ity. They appeared to be associated with the 
resorption of postovulatory follicles and atretic 
vitellogenic oocytes, as has been suggested by 
Ravaglia and Maggese (1995). The presence of 
vitellogenic oocytes is an unambiguous indica- 
tion of sexual maturity, and the length and age 
at which vitellogenic oocytes first developed in 
bonefish corresponded to the length and age at 
which PAS-positive melanomacrophage centers 
first appeared (Fig. 3). Melanomacrophage cen- 
ters were most abundant at the end of the 
spawning season, when spent fish were most 
common, and decreased in abundance during 
the postreproductive period (July-No- 
vember), when recrudescence occurred 
(Fig. 5). Ravaglia and Maggese (1995) 
found that the abundance of melanoma- 
crophage centers was also seasonal in 
Synbranchus marmoratus and peaked 
during the postreproductive season. 
Seasonality of gonad development 
Bonefish gonadal activity in the Florida 
Keys was seasonal, and development oc- 
curred over about eight months, from 
November to June. Bonefish were repro- 
ductively inactive for only a few months 
during summer. This period of inactivity 
roughly corresponds with the period of 
maximum water temperatures in the 
Keys (Crabtree et al., 1996). Bruger 
(1974) reported no evidence of a seasonal 
pattern of gonadal development for bone- 
fish off the Florida Keys, but his small 
sample size during July-September (n= 7 
females, n = 4 males) may have obscured 
seasonal patterns. Alexander (1961) 
Month 
Figure 5 
Monthly mean percent frequency of occurrence and standard errors of PAS- 
positive melanomacrophage centers in bonefish, Albula vulpes, ovaries. The 
numbers above the error bars are the numbers of ovaries examined. 
