LIFE HISTORY OF BLACKFISH 
93 
Water temp. Total sample Largest female Largest gravid female 
Month 
CC) 
N 
Mean GSI 
TL 
GSI (mm) 
TL 
GSI (mm) 
AN 
September 80 
11.9 
15 
2.22 
198 
5.77 
198 
5.77 
0 
October 80 
12.6 
11 
5.12 
207 
11.84 
207 
11.84 
0 
November 80 
17.0 
9 
4.90 
230 
0.95 
158 
10.48 
4 
December 80 
15.5 
17 
1.36 
242 
0.04 
116 
15.40 
10 
January 81 
24.5 
22 
0.33 
242 
0.38 
no gravid females 
- 
September 81 
11.9 
17 
1.05 
196 
2.45 
no gravid females 
October 81 
11.9 
13 
1.12 
177 
9.64 
177 
9.64 
0 
November 81 
11.0 
23 
3.20 
194 
0.01 
152 
9.46 
2 
December 81 
17.0 
18 
6.62 
178 
1.02 
117 
16.3 
7 
January 82 
22.0 
13 
0.38 
184 
0.42 
no gravid females 
- 
Table 2. Seasonal variation in GSI values and length of gravid females; N = number of females in monthly 
sample, AN = number of females larger than largest gravid female. 
Category 
Occurrence 
Number 
Dominance 
Rank 
Trichoptera 
76.0 
15.9 
24.4 
21.6 
Diptera 
67.6 
31.1 
8.3 
15.3 
Ephemeroptera 
81.1 
33.3 
29.4 
24.5 
Plecoptera 
33.5 
6.9 
3.2 
8.7 
Coleoptera 
27.3 
2.8 
3.0 
6.9 
Hemiptera 
4.7 
0.4 
0.9 
0.9 
Odonata 
4.0 
0.3 
1.5 
1.2 
Megaloptera 
LI 
<0.1 
1.2 
0.3 
Amphipoda 
14.6 
3.1 
3.0 
3.8 
Decapoda 
6.5 
0.4 
3.4 
1.8 
Isopoda 
1.5 
0.1 
0.4 
0.3 
Oligochaeta 
4.7 
0.3 
3.1 
1.5 
Arachnida 
1.1 
<0.1 
0.0 
0.3 
Terrestrial 
28.4 
4.4 
15.7 
8.7 
Fish eggs 
1.1 
0.5 
0.8 
0.5 
Galaxias olidus 
0.4 
<0.1 
0.4 
0.2 
Miscellaneous 
11.6 
0.3 
1.9 
3.2 
Table 3. Stomach contents of Gadopsis bispinosus from King Parrot Creek; n = 275. 
Occurrence = percentage of stomachs in which each category occurs; number = 
percentage contribution of each category to total number of food items; dominance = 
percentage of stomachs in which each category dominated volumetrically; rank = 
percentage composition of diet by rank method. 
appears that the spawning season extends over 
several months from about October to Decem¬ 
ber, that large females spawn earlier than small 
females, and that the onset of spawning coin¬ 
cides with an increase in water temperature in 
spring. 
The number of eggs in gravid ovaries ranged 
between 84 (fish TL = 121 mm) and 350 (fish 
1L - 207 mm). The relationship between total 
length and fecundity is described equally well by 
the relationships: 
Fecundity = 2.50 TL- 205; r 2 = 0.74; p < 0.001; 
and 
Log 10 Fecundity = 2.16 Log 10 TL - 2.50; r 2 = 0.72; 
p < 0.001 
The exponential relationship is probably more 
appropriate because the number of eggs in an 
ovary is governed more by the volume of the 
ovary (a cubic measure) than by its length. 
Nevertheless, the significance of the two correla¬ 
tions is identical. 
