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Abstract

This study describes the incidence of embryonic mortality and differential development
in southern calamary Sepioteuthis australis eggs. Late-stage S. australis egg strands harbouring multiple
embryos close to hatching were sampled from shallow (<4 m) Tasmanian spawning grounds
from early November 2000 to January 2001. Sepioteuthis australis embryos were found to develop
asynchronously within individual egg strands with proximal embryos developing slower and suffering
higher mortality than their distal siblings. The magnitude of asynchrony, however, differed
throughout the season with greater within-strand differences observed when embryos were exposed
to broader incubation temperatures. Unexpectedly, embryos developed more synchronously within
biologically fouled strands and displayed a significantly lower incidence of mortality compared to
those developing in unfouled strands. Embryonic mortality was initially low (4%) and significantly
increased to 20% in late November, remaining above 10% until late December. This dramatic
increase in mortality was not strongly associated with increasing water temperatures, but coincided
with a period of heavy rainfall alluding to potential salinity effects.

Item Type:	Article
Authors/Creators:	Steer, MA and Gowland, FC and Moltschaniwskyj, NA
Keywords:	Embryonic development · Mortality · Egg position · Biofouling · Asynchrony
Journal or Publication Title:	Marine Ecology Progress Series
ISSN:	Print 0171-8630 Online 1616-1599
Additional Information:	© Inter-Research 2002 · www.int-res.com
Item Statistics:	View statistics for this item

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