The respiratory responses and tolerance of hypoxia were studied in two marine teleosts, the red grouper (Epinephelus akaara, a sluggish species) and the black sea bream (Mylio macrocephalus, an active species). Neither species showed abnormal behaviour or mortality when exposed to 2 mg O2 l-1 for 7 h. The black sea bream was, however, comparatively more tolerant when exposed to 1 mg O2 l-1, but tolerance of both species became similar under extremely hypoxic conditions (i.e. 0.5 mg O2 l-1). In contrast to most other teleosts, both species showed a reduction in opercular beating rate during hypoxia, and oxygen conformity was found in the range of 0.5 to 7.0 mg O2l -1. O2 dissociation curves were constructed, and the P50 value of the black sea breams (27 ± 5.6 mm Hg) was found to be much lower than that of the red groupers (50 ± 2.5 mm Hg). For both species, the general levels of venous PO2 showed a direct relationship to ambient PO2, and were markedly reduced after 1 h exposure to various levels of hypoxia. Compared with the red groupers, the black sea breams appeared to be more able to maintain its venous PO2 levels during prolonged hypoxic exposure. Copyright © 1984 Dr W. Junk Publishers.
CitationWu, R. S. S., & Woo, N. Y. S. (1984). Respiratory responses and tolerance to hypoxia in two marine teleosts, Epinephelus akaara (Temminck & Schlegel) and Mylio macrocephalus (Basilewsky). Hydrobiologia, 119(3), 209-217. doi: 10.1007/BF00015211
- Respiratory responses
- Marine teleost