Muscle fine structure reflects ecotype in two Antarctic nototheniids

AM Sanger, W Davison, Stuart Egginton

Research output: Contribution to journalArticle


The fine structure of swimming (pectoral) and myotomal (axial) skeletal muscle and myocardium of two species of Antarctic nototheniid Fishes were studied by electron microscopy, comparing the cryopelagic Pagothenia borchrgrevinki and the benthic Trematomus bernacchii. Mean fibre size varied by a factor of four among muscles within each species and may have reflected the locomotory power available, being larger in pectoral oxidative (red) and axial glycolytic (white) muscle of P. borchgrevinki. Both species use labriform locomotion, and the more active P. borchgrerinki had a greater capillary supply, expressed as a capillary to fibre ratio. than T. bernacchii to both red (3.48 +/- 0.36 v. 1.63 +/- 0.14, mean +/- S.E.; P <0.01) and white (2.70 +/- 0.20 v. 1.53 +/- 0.18, mean +/- S.E.; P <0.01) regions of the pectoral musculature. The greater aerobic scope of P. borchgrevinki was strikingly demonstrated in the higher mitochondrial content of all skeletal muscle types sampled, and the ventricular myocardium (0.269 +/- 0.011 v. 0.255 +/- 0.012 mean +/- S.E.; P <0.05). Minor differences were found in other elements of fibre composition, with the exception of a five-fold greater lipid content in pectoral red fibres of P. borchgrerinki (0.074 +/- 0.014 mean +/- S.E.) v. T. bernacchii (0.010 +/- 0.003; P <0.05). Differences in muscle fine structure among species clearly reflected differences in their ecotype. (c) 2005 The Fisheries Society of the British Isles.
Original languageEnglish
Pages (from-to)1-16
Number of pages16
JournalJournal of Fish Biology
Publication statusPublished - 1 Jan 2005


  • myocardium
  • mitochondrial density
  • electron microscopy
  • skeletal muscle
  • capillary supply
  • fibre size


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