Bioenergetics of juvenile whitespotted bamboo shark Chiloscyllium plagiosum Anonymous (Bennett)

Abstract

This study establishes the bioenergetics budget of juvenile whitespotted bamboo shark Chiloscyllium plagiosum by estimating the standard metabolic rate (RS), measuring the effect of body size and temperature on the RS, and identifying the specific dynamic action (RSDA) magnitude and duration of that action in juvenile whitespotted bamboo sharks. The mean ±s.d. (RS) of six fish (500–620 g) measured in a circular closed respirometry system was 30·21 ± 5·68 mg O2 kg−1 h−1 at 18° C and 70·38 ± 14·81 mg O2 kg−1 h−1 at 28° C, respectively. There were no significant differences in RS between day and night at either 18 or 28° C (t‐test, P > 0·05). The mean ±s.d. Q10 for 18–28° C was 2·32 ± 0·06 (n = 6). The amount of oxygen consumed per hour inline image changed predictably with body mass (M; 295–750 g) following the relationship: inline image (n = 40, r2= 0·92, P < 0·05). The mean magnitude of RSDA was 95·28 ± 17·55 mg O2 kg−1 h−1. The amount of gross ingested energy (EI) expended as RSDA ranged from 6·32 to 12·78% with a mean ±s.d. of 8·01 ± 0·03%. The duration of the RSDA effect was 122 h. The energy content of juvenile whitespotted bamboo shark, squid and faeces determined by bomb calorimeter were 19·51, 20·3 and 18·62 kJ g dry mass−1. A mean bioenergetic budget for juvenile whitespotted bamboo sharks fed with squid at 18° C was 100C = 29·5G + 31·9RS+ 28·2RSDA+ 6·7F + 2·1E + 1·6U, where C = consumption, G = growth, F = egestion, E = excretion and U = unaccounted energy.