Heart, arteries, lungs, and cells of epaulette shark allow survival in low oxygen by reducing respiration rate.

“The epaulette shark (Hemiscyllium ocellatum) is a tropical marine vertebrate. It lives on shallow reef platforms that repeatedly become cut off from the ocean during periods of low tides. During nocturnal low tides, the water [O2] can fall by 80% due to respiration of the coral and associated organisms. Since the tides become lower and lower over a period of a few days, the hypoxic exposure during subsequent low tides will become progressively longer and more severe. Thus, this shark is under a natural hypoxic preconditioning regimen. Interestingly, hypoxic preconditioning lowers its metabolic rate and its critical PO·. Moreover, repeated anoxia appears to stimulate metabolic depression in an adenosine-dependent way.” (Nilsson and Renshaw 2003:3131)

Last Updated August 18, 2016