Squids typically demonstrate considerable plasticity in individual growth rates.
However, it is not known if individuals growing at different rates also differ at lower levels of organisation. We wished to determine if Sepioteuthis lessoniana individuals that were larger than predicted for their age differed in their digestive gland and mantle muscle tissue proximal composition or mantle muscle structure, compared with individuals that were smaller for their age than predicted. Juveniles had greater concentrations of lipid in their muscle tissue, perhaps due to an emphasis on storing energy reserves in this critical period of their life. This may be due to whole animal growth and changes in biochemical composition occurring on different time scales.