Buoyancy Role of Urea and TMAO in an Elasmobranch Fish, the Port Jackson Shark, Heterodontus portusjacksoni

@article{Withers1994BuoyancyRO,
  title={Buoyancy Role of Urea and TMAO in an Elasmobranch Fish, the Port Jackson Shark, Heterodontus portusjacksoni},
  author={Philip Carew Withers and G. K. Morrison and Michael Guppy},
  journal={Physiological Zoology},
  year={1994},
  volume={67},
  pages={693 - 705}
}
The Port Jackson shark is denser than seawater, like most other elasmobranchs. Its small liver, of relatively low lipid content, does not contribute significantly to buoyancy. Like other elasmobranchs, Port Jackson sharks accumulate high levels of urea and methylamines (trimethylamine oxide [TMAO] and betaine) in their body fluids as important balancing osmolytes. We calculate from the solute composition of plasma and muscle fluid, using molecular weights and partial molal volumes of solutes… Expand
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