The Evolution of Neutrally Buoyant Notothenioid Fi

Authors: J T Eastman

Publish Date: 1985

Volume: , Issue: , Pages: 430-436

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Abstract

Since all notothenioid fishes lack swim bladders one would expect them to be confined to predominantly benthic habitats There is however a trend towards the evolution of neutrally buoyant species which have become permanent members of the midwater community The absence of competition from other midwater fishes and trophic factors have probably been responsible for this trend Pleuragramma antarcticum Aethotaxis mitopteryx and Dissostichus mawsoni are neutrally buoyant Dissostichus mawsoni is the largest piscine predator in the midwaters of the Southern Ocean In McMurdo Sound D mawsoni eats predominantly’ fish and mysid shrimps The recently described nototheniid Cryothenia peninsulae a krilleating species from West Antarctica is not neutrally buoyant Evolutionary alterations in buoyancy are reflected as morphological specializations in the following body systems skeleton integument lipid storage muscles and viscera

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