GONAD MATURATION, MORPHOLOGICAL AND PHYSIOLOGICAL-CHANGES DURING THE FIRST REPRODUCTIVE-CYCLE OF THE CRAYFISH CHERAX-QUADRICARINATUS FEMALE

Concurrent morphological, anatomical and physiological changes took pl ace during the first reproductive cycle in the Australian red-claw cra yfish Cherax quadricarinatus, which prepared the female for spawning a nd holding of the newly deposited eggs. The endopod became longer and wider than the exopod and developed a mixture of plumose and long thin simple (ovigerous) setae. Small oocytes (0.24 +/- 0.05 mm) were prese nt in the immature ovary. The growing ovary contained two distinct ooc yte populations: one consisted of small (0.55 +/- 0.07 mm), barely gro wing oocytes, while the other consisted of large oocytes, which increa sed in size continuously (0.73 to 2.55 mm) until egg laying took place . A gradual change in the relative abundance of ovarian polypeptides o ccurred until the late vitellogenic stage (large oocytes > 1.8 mm). Th ree predominant female-specific, SDS-PAGE separated, polypeptides were observed (103, 78 and 73 kDa) that may represent vitellin subunits. T he most abundant carotenoid in the ovary was astaxanthin, while beta-c arotene was present at a lower concentration. The strong correlation b etween the increasing diameter of the oocyte and the concentration of astaxanthin in the ovary and in the hemolymph suggested an association of astaxanthin with vitellin and vitellogenin.