An experimental study of the combined effects of temperature and photoperiod on reproductive physiology of Pecten maximus from the Bay of Brest (France)
C. Saout et al., An experimental study of the combined effects of temperature and photoperiod on reproductive physiology of Pecten maximus from the Bay of Brest (France), AQUACULTURE, 172(3-4), 1999, pp. 301-314
The influence of environmental factors on reproduction and energy partition
ing was investigated in scallops (Pecten maximus) maintained in a hatchery
under 'winter' and 'spring' conditions of changing temperature and day-leng
th. Biometric measurements revealed that 'spring' conditions favoured gonad
growth whereas 'winter' conditions were associated with somatic growth (ad
ductor muscle and digestive gland). Biochemical analysis showed that in par
allel with gonad growth, total proteins, carbohydrates and lipids accumulat
ed in the female part of the gonad under 'spring' conditions. The lipid lev
el of the digestive gland, which was more than 40% of the dry weight under
both experimental conditions, emphasised the role of this organ in the stor
age of reserves. Quantitative histological analysis of oogenesis establishe
d that experimental conditions did not influence the total number of oocyte
s in the gonad but affected the partitioning between previtellogenic and vi
tellogenic oocytes. The contribution of vitellogenic oocytes was higher und
er 'spring' conditions. Energy partitioning was strongly influenced by expe
rimental conditions: 89% of the production was channelled into the gonad un
der 'spring' conditions compared with 40% under 'winter' conditions. (C) 19
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