Sewall and Rodgveller: Changes in body composition and fatty acid profile during embryogenesis of Sebastes maliger 
209 
Table 2 
Developmental staging scheme for quillback rockfish (Sebastes maliger ) embryogenesis. Stages 1 through 9 represent progres- 
sively developing embryos, whereas stage-10 samples contained many hatched larvae. Equivalent stages from Yamada and Kusa- 
kari (1991) are included for comparison. 
Yamada and 
Kusakari (1991) 
Stage 
Description 
stage 
1 
Embryonic shield (very small germ disc on one pole of egg) 
15 
2 
Head fold 
16 
3 
Optic vesicles 
17 
4 
Optic cups, increased orbital definition 
20 
5 
Early retinal pigmentation 
25 
6 
Retinal pigment light, spreading throughout eye; body pigment appears as scattered dark dots 
along ventral side of tail 
25-28 
7 
Very slight eye shimmer appears; body pigment increased slightly, still ventral 
25-28 
8 
Eye shimmer increases, scattered throughout the darkening retina; body pigment increases >2x, 
still ventral, spots merging to form a line 
25-28 
9 
Retina dark with a lot of shimmer scattered throughout, some black still visible; pigmentation on 
gut behind yolk sac and dorsally along tail 
25-28 
10 
Dark retina covered with shimmer, body pigment blended into a dark line on ventral side of tail, 
spots also on dorsal side of tail and on peritoneal wall; hatched/hatching imminent; yolk not depleted 
29-31 
Figure 1 
Quillback rockfish (Sebastes maliger) stage-1 embryo (left) and stage-10 hatched larva 
(right). 
tilization; however, we 
did not possess data 
on the gestation period 
for quillback rockfish. 
The period of gestation 
seems to vary widely 
among rockfish spe- 
cies (e.g., 29 days for 
S. flavidus [Eldridge et 
al„ 2002], 48 days for 
S. schlegelii [Yamada 
& Kusakari, 1991]), as 
well as the time spent 
at each stage of devel- 
opment, so we did not feel confident in assigning esti- 
mated time durations to each stage based on studies of 
other rockfish. However, we were more concerned with 
general trends during development, and net differences 
in body composition as embryos become larvae, than 
the precise rates of change among stages. In addition, 
other studies have reported developmental changes in 
body composition using stages assumed to represent 
equal intervals (e.g., MacFarlane and Norton, 1999); 
to facilitate comparisons, we also chose to follow this 
convention. 
To assess net changes in body composition that oc- 
curred over the course of embryogenesis (i.e., differences 
between early embryos versus hatched, preparturition 
larvae), data on body compositions were averaged from 
three samples at the earliest available stages (stages 2 
and 3) and compared with values averaged from four 
late-stage samples (stage 10). To describe trends and 
variability in lipid and protein use across all stages 
of development, protein and lipid masses were plotted 
against developmental stage and the strengths of the 
correlations were calculated. Samples at stages 1 and 9 
were excluded from biochemical analyses due to techni- 
cal constraints, such as insufficient sample masses for 
some processes. 
Wet tissue mass The average wet tissue mass of embryos 
and larvae at each developmental stage was determined 
for use in calculations of body composition. A subsample 
of ~100 embryos or larvae removed from a maternal fish 
was placed on filter paper to drain intraovarian fluid. 
The subsample was then weighed to the nearest 0.1 mg, 
and individuals were counted under a dissecting micro- 
scope. This was repeated three times per female, and 
data from the three replicates were used to calculate 
an average wet mass per embryo or larva. These sub- 
samples were discarded to prevent degraded or oxidized 
samples from being included in biochemical analyses. 
