Sewall and Rodgveller: Changes in body composition and fatty acid profile during embryogenesis of Sebastes maliger 
213 
Figure 2 
Protein mass (A) and lipid mass (•) per embryo or 
larva by developmental stage for quillback rockfish 
( Sebastes maliger). Development progresses from left 
to right: Stage 2 = early embryos (postfertilization); stage 
10=hatched larvae (preparturition). Each point repre- 
sents a single measurement of a composite sample of 
hundreds of embryos/larvae from one maternal female 
(n = ll maternal females). Only data from samples for 
which protein and lipid analyses were both completed are 
included. For lipid mass, two stage-10 points overlap and 
are indistinguishable. Lipid: r 2 = 0.54, y=-1.90x+48.96. 
Protein: r 2 = 0.35, y=-2.37x+98.02. 
While lipid and protein were both consumed in sig- 
nificant amounts, lipid was lost at a greater rate as a 
proportion of initial lipid mass (34%) than was protein 
(19%). Though both declined during development, there 
was greater variability and a weaker correlation be- 
tween protein mass and developmental stage than lipid 
mass and stage (Fig. 2). 
Using these mass losses to estimate energy use (Table 
3), a developing embryo consumed a minimum of 0.88 J 
of energy, on average, with approximately 0.53 J (60%) 
coming from lipid and 0.35 J (40%) from protein. The 
slight decrease (8%) in the energy density of dry tissue 
mass was due to greater proportional losses of lipids 
than proteins. The 26% decline in total energy content 
per individual was thus more a reflection of the 20% 
loss in total dry mass than of the changes in propor- 
tions of lipid and protein. 
Oil globule volume 
The volume of the oil globule in rockfish embryos and 
larvae reflected both their developmental stage and 
body composition. OGV declined by 51% from early-stage 
embryos to hatched larvae. The OGV was highly cor- 
related with developmental stage (Fig. 3). As embryos 
progressed through developmental stages, changes in 
Figure 3 
Oil globule volume in nanoliters (nL) by developmen- 
tal stage for quillback rockfish (Sebastes maliger) 
embryos and larvae. Development progresses from left 
to right: Stage 2 = early embryos (postfertilization); 
stage 10 = hatched larvae (preparturition). Each point 
represents the mean oil globule volume calculated from 
diameter measurements of approximately 24 embryos 
or larvae from each maternal female (n = ll maternal 
females); two stage-10 points overlap and are indistin- 
guishable. Only data from samples for which protein 
and lipid analyses were both completed are included. 
r 2 =0.89, y=-1.78x+32.27. 
OGV indicated trends in overall lipid and protein levels. 
Simple linear regression analysis indicated that total 
lipid was significantly dependent upon OGV (Table 4); 
this held true whether lipid was expressed as lipid mass 
per individual, or concentration (percentage of wet or dry 
tissue mass). Protein mass also decreased with OGV, 
though this relationship was weaker. 
Fatty add profiles 
The proportions of fatty acids (FAs) present in quill- 
back rockfish appeared to change during their early 
development, as indicated by the significantly differ- 
ent FA compositions of early embryos versus hatched 
larvae (ANOSIM R= 0.677, a=0.05, n- 8). An MDS plot 
of the samples based on their Aitchison matrix distances 
showed a distinct separation of the early and late-stage 
FA profiles (Fig. 4). 
The highest percentage mass losses (> 60%) of indi- 
vidual FAs were found to occur among the n-11 mono- 
unsaturated fatty acids (MUFAs) 18:ln-ll, 20:ln-ll and 
22:ln-ll; and the polyunsaturated fatty acids (PUFAs) 
18:3n-3 (alpha-linolenic acid) and 20:3n-3 (eicosatri- 
enoic acid) (Eq. 2; Fig. 5). The lowest percentage losses 
(<20%) occurred for the saturated fatty acid (SFA) 18:0 
(stearic acid), the MUFA 24:ln-9 (nervonic acid), and 
