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Fishery Bulletin 95(4), 1 997 
Biological characteristics of harvest 
Length-based estimates of maturity and age were 
calculated for artisanal catches. Additionally, in 
1994-95 we measured the catches of 19 groups of 
1-4 fishermen (rc=43) who had fished together, to de- 
termine their average catch per unit of effort (CPUE: 
kg/h per person). The principal method was spear fish- 
ing by free diving; data are presented for that gear only. 
Results 
Length, weight, sex, and maturity 
A complete size range of newly settled, juvenile and 
adult A. lineatus was present in rotenone-treated 
samples from shallow nearshore waters <2 m deep 
(Fig. 3), but large fish were underrepresented because 
some avoided capture. Night spear fishermen har- 
vested the larger fish, generally 15-21 cm FL. 
Males and females taken in the fishery were of 
similar length (t= 0.26, df=993, P=0.8) and the sex 
ratio was nearly equal (1 male: 1.1 females, n= 995). 
Length-weight relations for the sexes did not differ sig- 
nificantly ( ANOVA, F=0.07, P=0.79); thus all fish were 
pooled, including smaller unsexed fish: log weight (g) = 
-1.60 + 3.03 log length (FL in cm)(r 2 =0.99, n=l,047). 
The relation between FL and standard length in cm 
was SL=0.86(FL) - 0.38 (^=0.99, n=94). 
Mature fish of both sexes generally had well-de- 
veloped gonads (6.2 ± 0.2 g, n= 529) or gonads that 
appeared to be partly or wholly spawned out (1.2 ± 
25 
Fork length (cm) 
Figure 3 
Sizes of A. lineatus in the artisanal fishery, all years com- 
bined ( 1987-95), and those collected in rotenone-treated shal- 
low waters. 
0.1 g, n=108). Immature fish had little gonad devel- 
opment (0.2 ± 0.01 g, n= 502). Fish reached sexual 
maturity at 15-21 cm FL (Fig. 4), with males matur- 
ing at a slightly smaller size than females. Half of 
both sexes were mature at about 18 cm, i.e. at ap- 
proximately 4 years of age. 
Spawning 
The gonadosomatic index (GSI) was highest during 
October-February (Fig. 5) and was strongly corre- 
lated with daylength and feeding hours (Table 1). 
Spawning also occurred throughout the year. Dur- 
ing all months, groups of 50-200 fish were observed 
spawning at dawn in the outer portion of the outer 
reef channel at Afao (see Fig. 2). Additional details 
are provided elsewhere (Craig, in press). 
Settlement of young onto reef 
Newly settled fish (n= 575) exhibited both light (79%) 
and dark (21%) color phases. 6 Settlement peaked in 
March-April with densities of 0.4-0. 6 recruits/m 2 on 
