Morphometrics and ultrastructure of myocardial tissue in Notothenioid fishes

• Published in: Fish Physiology and Biochemistry
• Main Authors: Johnston, Ian A., Harrison, Paul
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 1987
• Subjects: Biology and Microbiology; Antarctic; Antarc*; Icefish
• Online Access: http://nora.nerc.ac.uk/id/eprint/522787/; https://doi.org/10.1007/BF02183988

Antarctic fish of the family Channichthyidae (Icefishes) lack the respiratory pigments haemoglobin and myoglobin. The morphometrics and ultrastructure of the ventricular myocardium of a benthic icefish,Chaenocephalus aceratus has been compared with that of a red-blooded Notothenioid fish,Notothenia neglecta, of similar habit. The mass of ventricular muscle as a percentage of bodyweight is 3 times greater in adultC. aceratus (0.32%) thanN. neglecta (0.11%). Myoglobin concentration in the ventricle ofN. neglecta, 20 nmoles/g, is comparable to that of temperate teleosts with similar activity patterns. The volume and surface densities of mitochondria are 41.5% and 0.32 μm−1 for Icefish and 25% and 0.15 μm−1 forN. neglecta, Cytochrome oxidase activities are similar in the two tissues whilst the volume density of myofibrils is higher forN. neglecta (47%) thanC. aceratus (29.9%). The proliferation of mitochondria in the myocardium of Icefish will reduce the diffusion path-length for oxygen between ventricular lumen and the outer mitochondrial membrane and may compensate for the absence of myoglobin.