The distribution, embryological development and effects of temperature on the eggs and larvae of Pleuragramma antarcticum from Terra Nova Bay, Antarctica

Little is known of the early development of Pleuragramma antarcticum prior to hatching. Abundant eggs and larvae were collected under the sea ice from Terra Nova Bay in October and November. The distribution, embryological development and biochemical changes in these eggs and larvae was the scope of an international investigation with particular emphasis on their resistance to freezing. Cores of congelation ice were sectioned to check for viable eggs in the solid ice at several sites between Coulman Island and the Drygalski Ice Tongue. A total of 118 sites were visited and tested for the presence of Pleuragramma eggs or larvae. Eggs which were found were kept in a flow through aquaria and sampled every 1 or 2 days to assess development. Eggs were examined and photographed under a dissection microscope and fixed for histological examination and to evaluate modern DNA haplotypes of the Ross Sea Pleuragramma population. Freezing and melting points of eggs, larvae and associated body fluids was done by microscopic observations in a cryometer.