The physiological tolerance of the grey carpet shark (<Emphasis Type="Italic">Chiloscyllium punctatum</Emphasis>) and the epaulette shark (<Emphasis Type="Italic">Hemiscyllium ocellatum</Emphasis>) to anoxic exposure at three seasonal temperatures |
| |
| Authors: | Clint A Chapman Blake K Harahush Gillian M C Renshaw |
| |
| Institution: | (1) UnderWater World, Parkyn Parade, Mooloolaba, Sunshine Coast, QLD, 4557, Australia;(2) School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia;(3) Hypoxia and Ischemia Research Unit, School of Physiotherapy and Exercise Science, Griffith University, Gold Coast Campus, Gold Coast, QLD, 4222, Australia |
| |
| Abstract: | The epaulette shark (Hemiscyllium ocellatum) and the grey carpet shark (Chiloscyllium punctatum) are commonly found in periodically hypoxic environments. The ecophysiological time available for these animals to safely
exploit these niches during different seasonal temperatures was examined. The time to loss of righting reflex (T
LRR) was examined in response to an open ended anoxic challenge at three seasonal temperatures (23, 25 and 27°C). Ventilation
rates were measured in an open ended anoxic challenge at 23°C and during 1.5 h of anoxia followed by 2 h of re-oxygenation
at 23 and 25°C. The mean T
LRR of epaulette and grey carpet sharks was inversely proportional to temperature. The T
LRR was similar between species at 23°C; however, grey carpet sharks had significantly reduced T
LRR at higher temperatures. During the standardised anoxic challenge, epaulette sharks entered into ventilatory depression significantly
earlier at 25°C. During re-oxygenation, epaulette sharks exposed to anoxia at 23°C had no significant increase in ventilation
rates. However, after anoxic challenge and re-oxygenation at 25°C, epaulette sharks showed a significant increase in ventilation
rates during re-oxygenation. Grey carpet sharks displayed no evidence of ventilatory depression during anoxia. However, during
re-oxygenation, grey carpet sharks had significantly elevated ventilation rates above pre-experimental levels and control
animals. These data demonstrate that the anoxia tolerance times of both species were temperature dependent, with a significant
reduction in the T
LRR occurring at higher temperatures. Epaulette sharks had a significantly greater T
LRR at higher temperatures than grey carpet sharks, which did not enter into a ventilatory depression. |
| |
| Keywords: | |
| 本文献已被 PubMed SpringerLink 等数据库收录！ |
|
