COD EGG CHARACTERISTICS AND VIABILITY IN RELATION TO
LOW TEMPERATURE AND MATERNAL NUTRITIONAL CONDITION
P.
Ouellet, Y. Lambert, I. Bérubé-2001
ICES Journal of Marine Science, 58(3) : 672-686
Abstract :
In1995 and 1996, groups of female cod (Gadus
morhua) of varying nutritional condition and maturing at
different temperatures were used to investigate relationships between female condition, egg production, egg
characteristics, and viability. Over the two years,
egg samples from every batch spawned by 34 females
were analyzed for egg diameter, dry mass, and energy content. In addition, 51 egg batches from 24 females (ca.2
egg batches female-1yr-1) were used to monitor development
rate and hatching success. The weighted mean egg dry
mass was positively correlated (p<0.05) to the
females' pre-spawning condition in 1996. In 1995 this
positive correlation was not observed for females at
~2°C during maturation. For both years, the decline
in the mean egg dry mass per batch throughout spawning
was correlated (p<0.05) with the females'
post-spawning energy reserves. However, no trend in
the total egg dry mass per batch during the sequence
of spawning was observed. Thus, the total energy investment
per batch remained stable throughout spawning and was
not influenced by the depletion of the females' energy
reserves. In 1996, high hatching successes were
observed only for egg batches from females in high
pre-spawning condition. However, egg size and dry mass showed no correlation with survival rate or
hatching success in either year.
(Fisheries and Oceans Canada, Maurice Lamontagne Institute, C.P. 1000,
Mont-Joli, (Québec), Canada, G5H 3Z4, Tel.: +1 (418) 775-0675; e-mail:ouelletp@dfo-mpo.gc.ca)