622 
Fishery Bulletin 95(3), 1997 
Table 1 
Meristic relations between totoaba standard length (SL) and total length (TL), otolith length (OL), otolith thickness (OT), and 
otolith weight (OW). For otolith measurements, n = 118. 
Parameter 
Equation 
T 2 
Fish total length (TL) 
SL = 0.91 TL - 26.34 (n=951) 
0.99 
Otolith length (OL) 
SL = 16.91 exp(4.7( l-exp(-0.96 x OL))) 
0.99 
Otolith thickness (OT) 
SL = 8.53 exp(5.4( l-exp(-0.17 x OT))) 
0.98 
Otolith weight (OW) 
SL = 788.8 x OW° 4518 
0.99 
Results 
From shrimp trawl nets, 1,125 juvenile totoaba ( 100- 
600 mm SL, mean=223, SD=65 mm SL) and 157 
adults were collected (600-1,850 mm SL, mean 
= 1,360, SD=89 mm SL). Figure 3 shows the length- 
frequency distribution for the specimens 
collected. 
Totoaba sagittal otoliths are large and beanlike, 
as are most sciaenid otoliths (Secor et al. 4 ). Table 1 
shows the linear equation describing the relation 
between SL and TL, the Gompertz relations between 
SL and otolith length (OL), otolith thickness (OT), 
and the allometric equation for the SL and otolith 
weight (OW) relation (Fig. 4). Otolith growth in 
weight changes in relation to fish growth in length 
and is an allometric, not isometric relation (6=2.176, 
H o : b =3.00, student’s Gtest (0 025 m) =21.41). 
Transverse sections of the totoaba otolith (Fig. 5) 
typically showed clear, opaque, and translucent zones 
and when the otolith is sectioned exactly through the 
focus, the core appears as a dense opaque zone, next 
to which the first annulus is found. The distance be- 
tween the core and the first annulus is variable but 
is typically greater than increment sizes between the 
remaining annuli. The relation between otolith ra- 
dius (OR) along radius 1 and SL (Fig. 6) was fitted to 
a Gompertz function: 
SL = 30.92 x exp(3.86(l-exp(0.99 x OR))), 
[r 2 =0.98, n=94]. 
We found specimens representing 15 year classes 
between 0 and 24 years (Table 2). Of the 101 read- 
able otolith sections, 66 fish were young-of-the-year 
(110-377 mm SL). Ten juveniles were of age class 2 
