Energy demand during exponential growth of Octopus maya: exploring the effect of age and weight

Abstract

Recent work has reported changes associated with physiological, morphological, and behavioural adaptation during the absorption of yolk reserves. The holobenthic endemic species Octopus maya was used to explore the energy supply needed from the food intake (I

J animal(-1) d(-1)) to supply the rate of production energy needed for body mass (P

J animal(-1) d(-1)) and respiration rate (R

J animal(-1) d(-1)) as a function of weight and age during the exponential early growth phase of the animal. Individually housed juveniles from hatching (1 d) to 105 d after hatching (DAH) were used, with the age and weight known, and the relationship between oxygen consumption (VO2

mg O2 animal(-1) d(-1)) and weight (g) was established. Projections of I, R, and P as a function of age (Z) were made. The food intake destined to supply body mass production (% P/ I) and respiration rate energy (% R/ I) was analysed for an extended age range of 1-150 DAH. When O. maya juveniles hatched, they had a greater requirement for R than for P from the food intake, 61% (% R/ I) and 13% (% P/ I), respectively, suggesting high metabolic cost associated with post-hatching (during yolk absorption). Within the period where ZR. ZP (1-105 DAH), there was sufficient metabolic energy to satisfy the demands for sustaining exponential body mass production. The age at which % R/ I % P/ I delimits the point where P cannot increase for reasons of metabolic constraint.