Differential responses of juvenile and adult South African abalone (Haliotis midae Linnaeus) to low and high oxygen levels

Metabolic readjustment in juvenile South African abalone (Haliotis midae) acclimated to combinations of temperature and dissolved oxygen levels

“…2A). When we compare our data with those from Vosloo et al (2013), there seems to be compensation for the increase in temperature between 14 1C and 16 1C for all treatments (Q 10 of 2.0, 3.6 and 2.5), but not between 16 1C and 19 1C for all treatments (Q 10 of 0.2, 0.2 and 0.01). We calculated the oxygen consumption rates expected at the three different oxygen treatments at 19 1C, had the Q 10 remained the same between 16 1C and 19 1C as for the 14-16 1C interval.…”

“…In addition, we demonstrated that winter-acclimated juvenile H. midae were less susceptible to longterm re-acclimation to low and high oxygen levels at 16 1C compared with adults (Vosloo et al, 2013). These two singlefactor studies revealed valuable insights into the physiological constraints and mechanisms that underpin environmental adaptation in temperate abalone.…”

“…Only average oxygen consumption rate and nitrogen excretion rate data were used to calculate O:N ratio, as described in Vosloo and Vosloo (2010). Oxygen consumption rate, nitrogen excretion rate and O:N ratio data for 16 1C, 82%, 98% and 126% oxygen saturation reported in Vosloo et al (2013) for juvenile abalone are provided in the results section of this paper for comparison to data from 14 1C and 19 1C treatments. Direct comparisons are possible, since the animals from this study and the Vosloo et al (2013) study were exposed simultaneously.…”

“…Whole-animal oxygen consumption rate, using closed system respirometry (Strathkelvin 791), and nitrogen excretion rate using accumulation of nitrogen in a closed system over time, for six to ten animals per treatment was measured as described in Vosloo et al (2013). The atomic equivalents of oxygen consumed and nitrogen excreted was used to calculate the O:N ratio to determine the relative importance of protein as metabolic fuel (Bayne et al, 1985).…”

“…midae acclimation and re-acclimation were carried out at the on-farm laboratory at Irvin & Johnston Limited, Abalone Division (Gansbaai, South Africa) and the conditions were as reported for juvenile abalone exposure at 16 1C in Vosloo et al (2013). Juvenile abalone were obtained from a single spawning of a group of wildcollected brood stock animals collected from various locations within their natural distribution range.…”