Marine Biodiversity and Ecosystems

Ecology and early development of Antarctic fishes

Principal Investigator: John Macdonald
Organisation: University of Auckland

Earlier work has studied the density and variability of populations of a common bottom-dwelling fish, Trematomus bernacchii. Population estimates were made using mark and recapture and video bait stations. Results will provide a basis for assessing effects of human activities on Ross Sea fish populations, and for evaluating any proposed commercial fishery.

More recently, work has turned towards the early development of the pelagic Antarctic silverfish. Many Antarctic fishes are in contact with sea ice during larval development, and the Antarctic silverfish Pleuragramma antarcticum, is a key species in the trophic structure of the Antarctic marine ecosystem. Very little is known, however, of the early development of P. antarcticum prior to hatching. Over the past 4 years, members of this programme have discovered how to obtain fertilised eggs from P. antarcticum, and from a second very different species, the bottomdwelling naked dragonfish (Gymnodraco acuticeps).

Our programme involves an international collaboration between New Zealand, Italian and American scientists to document embryological development and biochemical changes in the first species. Particular emphasis is placed on determining the true extent of the putative spawning ground, and estimating the total mass and distribution of eggs. Additional projects include ion transport, freezing resistance and the ontogeny of antifreeze production, morphological and metabolic changes associated with the transition from yolk to feeding, and changes in body density, lipid composition, fins and muscle activity associated with the onset of locomotion.

Recent Publications
Vacchi, M. et al. Early life stages in the life cycle of Antarctic silverfish, Pleuragramma antarcticum in Terra Nova Bay, Ross Sea. Antarctic Science 16(3): 299-305, 2004. View Abstract.

Herbert et al. A difference in optomotor behaviour of two Antarctic nototheniid fishes is correlated with the presence of choroid rete mirabile and Root effect. Polar Biology 26: 411-415, 2003.