Nudibranch Egg masses

July 19, 2002
From: Laurette Hanekom

Dear Dr. Rudman
I am interested in the egg deposits of nudibranchs and have three questions.

1. What determines the colour of the egg mass? Is it influenced by what they eat?
2. How long does it take before the eggs hatch?
3. What happens to the nudibranchs once they hatch? Do they just float along with the current or do they live and feed around the place that the egg mass was deposited?

I have attached 3 slides of nudibranch egg masses which vary in texture and colour. On slide 1 the eggs are encased in a jelly-like substance and the eggs differ in texture from other egg masses found. The eggs are very close together and can not be distinguished with the naked eye. Is this perhaps a recently deposited mass? Do the eggs grow in size and then loosen the texture of the egg mass? Slides 2 and 3 show eggs that are more easily distinguishable and also differ in colour from pink to red. Does the colour of the egg mass change as it matures?

A long question I know, but I would appreciate any information on this subject which has long held my interest.

Many thanks
Laurette Hanekom
South Africa

Hanekom, L., 2002 (Jul 19) Nudibranch Egg masses. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Laurette,
The best way to find some information on eggs and development is to go to the GENERAL TOPICS INDEX and look at entries concerning 'eggs' and 'larvae'. If you look down through the messages on each page you will find a lot of information on each topic. Unfortunately at present I haven't had the time to prepare summary accounts on these inetersting topics. Another way to find things in the Forum is to use the SEARCH button.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jul 19). Comment on Nudibranch Egg masses by Laurette Hanekom. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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