ASCORBIC-ACID IN THE GONADS OF NORTH-SEA DAB (LIMANDA-LIMANDA) DURINGTHE REPRODUCTIVE-CYCLE

Total ascorbic acid was measured in the gonads of North Sea dab (Liman da limanda) throughout one reproductive cycle. In the ovaries, the con centration of ascorbate began to increase during the resting period in summer and reached maximum values of 400 mu g.g fresh weight (fw)(-1) at the onset of ovary maturation in fall. Concentrations declined rap idly towards the spawning period in spring and reached the lowest valu es of 80-100 mu g.g fw(-1). The maximum deposition of ascorbate in the ovaries amounted to 2.5 mg.organ(-1) and occurred in late winter, cor responding to the beginning of the spawning period. In the testes, asc orbate concentrations were lower than in the ovaries, reaching a maxim um of 170 mu g.g fw(-1) in early fall. The lowest values of 20-60 mu g .g fw(-1) appeared in winter and spring. In the testes the highest dep osition of ascorbate amounted to 110 mu g.organ(-1) and appeared at th e beginning of maturation. The sexual differences and seasonal variati ons are discussed in relation to the reproductive biology of dab.