The relationships of ovary weight, liver weight and visceral lipid stores to body weight in the goldfish were examined at different times of the year. Both arithmetic and logarithmic relationships were examined. Ovary weight significantly increased relative to increasing body weight in goldfish and the exact nature of this relationship changed from month to month. However, larger fish were found to have proportionately larger ovaries than small fish at specific times of the year. Regression lines for liver weight versus body weight were also determined. Monthly differences were found in the liver weight-body weight relationship. Visceral lipid stores expressed per gram of protein were found to be independent of body weight. Lipid stores expressed in this manner peaked in February while ovary weight peaked in April. The consequences of compensating for body size when expressing organ (liver, ovary) sizes, such as hepatosomatic index and gonosomatic index, are discussed.

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Liver glycogen, liver lipid, liver triglycerides, plasma glucose, plasma total lipid, plasma cholesterol, plasma corticoids, hypothalamic serotonin and pituitary prolactin levels were assayed at five times over a 24-h period in Carassius auratus maintained under a specific photoperiod regime at various times throughout the year. Diurnal variations were observed in all parameters monitored. Daily variations of liver glycogen, plasma glucose, plasma lipid, plasma corticoids and hypothalamic serotonin were affected by time of feeding. Liver glycogen, plasma lipid and plasma corticoid levels were also affected by time of feeding. Diurnal variations of liver glycogen, plasma glucose and plasma lipid were influenced by lightdark cycles. These data illustrate that feeding time, photoperiod and time of sacrifice are important considerations in the study of metabolic and hormonal parameters in fishes.

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