Gillanders: Trace metals in four structures of fish and their use for estimates of stock structure 
417 
Juveniles 
Adults 
0 25 
0.20 - 
0.16 - 
0.11 
0.07 
0.02 
3 - 
CD 
CD 
J I I I I 
0 07 
0 06 
0 05 
0.03 
0 02 
Eye lenses 
+ 
_i i 
I 
1 
I H 
t- 
2 " 
12 3 4 
Scales 
4 - 
J L_ 
7 " 
6 - 
9 
Spines 
6 - 
5 ' fH 
6 
| 
4 - 
2- C 
1 - 
n 1 l i 
3 
1 1 rt 
2 - 
U 
0 12 3 
0 
4 5 
0 12 3 4 
o L 
|ig Ba / g otolith 
Figure 4 
Relation between concentration of barium in otoliths (mean ±SE) and in eye 
lenses, scales, and spines of juvenile and adult fish (mean ±SE) collected 
from ten locations along the coast of New South Wales. 
the market value of the fish, then it is recommended that 
either scales or spines are the best alternative structure 
because these were the structures that were significantly 
correlated with the otolith elemental data for both juve- 
nile and adult fish. However, before using either of these 
structures, a number of fish (e.g. 30-50) should be collect- 
ed from three to four locations and the alternative struc- 
ture, as well as otoliths, should be analyzed. Classification 
models should then be developed by using data from each 
structure and the error rates should be compared. This 
was beyond the scope of the present study because sample 
sizes from each location were relatively small. 
0.060 r 
0.045 
0030 
0.015 
0 000 
.o 
CL 
2 0 
1.5 
1.0 
0.5 
0.0 
J I L. 
0.0 0 1 02 0 3 04 0 5 
Scales 
- 4 - 
J I I L. 
0 0 0.1 0.2 0.3 0 4 0.5 
Spines 
0.0 0.1 0.2 0.3 0.4 0.5 
pg Pb / g otolith 
Figure 5 
Relationship between concentration of lead 
in otoliths (mean ±SE) and in eye lenses, 
scales, and spines of adult fish ( mean ±SE ) 
collected from ten locations along the coast 
of New South Wales. Juveniles are not 
shown because concentrations of lead were 
below detection limits. 
Scales and spines may offer certain advantages over 
otoliths because they provide a nonlethal alternative. In 
addition, they can be collected relatively quickly and eas- 
ily. Scales may also require less preparation for analyses 
than either spines or otoliths. Thus, scales and spines may 
provide an alternative structure for determining stock 
identity. 
