Can the mudskipper, Periophthalmus chrysospilos, tolerate acute environmental hypoxic exposure?
The mudskipper P. chrysospilos became inert at 0.76 μl O2.ml(-1) when it was allowed to respire in a 'closed respiratory chamber'. No ethanol was detected although it excreted three times more total carbon dioxide into the surrounding sea water than the amount of oxygen consumed. However, P. chrysospilos could survive environmental hypoxic exposure (0.8 μl O2.ml(-1)) for at least 6 h. Upon normoxic recovery, the oxygen debt repayment was only a small fraction of the oxygen deficit incurred during the 6 h of hypoxic exposure. It would therefore appear that P. chrysospilos was able to cope with environmental hypoxia by suppressing its metabolic rate.
Department of Zoology, National University of Singapore, Kent Ridge, Singapore, 0511.
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