Cod (Gadus morhua L.) from the Arcto-Norwegian stock that spawns off northern Norway were caught at various times during their gonadal maturation cycle over a period of 16 months. The ovaries were removed and either fixed for histological work or deep-frozen for the determination of vitamin A compounds.

The ovaries were inactive from June to September. Maturation began in late September-October and fully ripe eggs were present in February-March, the range of sizes being 500-650 /x. After spawning there was a period of resorption and regeneration, until May, followed by the quiescent summer period.

dry matter rose from about 16 to 29%; the total amount of vitamin A aldehyde, vitamin A esters and alcohol, carotenoids and lipids in the ovaries also increased, though the concentrations of the carotenoids and vitamin A esters + alcohol on a dry-matter basis fell. Vitamin A aldehyde was only found in maturing ovaries and in February, just before spawning, the weight ratio of aldehyde to esters + alcohol was about 10 to 1. The other substances were present in resting ovaries. The appearance of aldehyde in the ovaries occurred when there was histological evidence for the onset of vitellogenesis.