Issues:
Sections:
Issue 99
GENERAL BIOLOGY
UDK: 593.96-116(268.52)
MORPHOMETRY OF THE GONADS AND CELLULAR COMPOSITION OF GONADAL TUBULES IN FEMALE HOLOTHURIAN MOLPADIA BOREALIS M. SARS, 1859 FROM THE KARA
This study describes the morphology and cellular composition of ovaries in the Arctic holothurian Molpadia borealis from the Kara Sea during autumn. All analyzed specimens were female. The gonads consisted of thin (0.1-0.2 mm) and thick (0.3-0.5 mm) tubules, which varied in their proportions of developing oocytes. The tubule wall was thin (7-17 µm). The lumen was predominantly filled with large oocytes (165-195 µm, 230-250 µm, and 260-270 µm in diameter), while smaller germ cells (50-95 µm) and individual ~130 µm oocytes lined the periphery. Developing oocytes featured a single peripheral nucleolus that enlarged during oogenesis. Gametes ?165 µm showed signs of resorption. At all stations, a portion of oocytes was in final maturation, indicating a pre-spawning or spawning-ready condition. Total fecundity was low, estimated at 150,000-200,000 cells per gonad, of which approximately 75,000 were mature oocytes (230-270 µm) ready for release.
Pages: 6 - 11
Date: 30.12.2025