Dear Karen,
Sometime when I have time I will prepare a page on larval development. In the meantime, have a look at pages in the General Topics List which are concerned with 'larvae' and 'eggs'. Make sure you look at the messages on each page as they and the associated answers often have more relevant material.

Basically the time between egg-laying and hatching differs in different species and can range from a few hours to 3 weeks or more. In most cases (we think) the egg develops in its capsule into a microscopic shelled veliger larva which hatches out into the sea where it lives and feeds, again for a variable period of time depending on the species. Some larvae don't feed and spend only a short period in the plankton.

In some cases the eggs develop directly into a little crawling slug which hatches out of the egg capsule which is usually laid on the preferred food of the species.

If you have further question please ask,
Best wishes,
Bill Rudman.

Dear Caroline,
Keeping opisthobranch larvae alive is a very specialised business. Some basic needs for the veliger larvae are:
* appropriate planktonic algae for feeding
*some mechanism to stop the larvae being caught in the surface film.

You then need to find what triggers settlement of the larvae so that it can settle out of the plankton and metamorphose into a crawling slug. For this you need to know the food of the particular nudibranch you are rearing, as settlement is often triggered by chemical cues from the adult food.

Sudden death of all the larvae could be because of a bacterial/protozoan infection or a sudden change in physical conditions, or it could have been because the larvae were starving and finally all died, or had delayed metamorphosis to the maximum limit without finding anything suitable to settle and metamorphose on.

As a first step then, you need to identify the species of nudibranchs you are trying to breed. I am sure almost every species will need special requirements. I can help you with identifications, if you can send photographs, but I don't know if I can give you more than broad clues to what they will eat.

There are a few references on Larval Culture page, below your message, and if you got to the General Topics Index you will find some other references to particular larvae. I'm sorry I can't be more specific, but I'm afraid I have never worked in a place with the facilities to study larvae. Although I am fascinated to read about larval studies, I am afraid my first-hand experience is very limited.

Best wishes,
Bill Rudman.

Dear Roberto,
Looks like you are having some success. Have you tried feeding the settled larvae on small pieces of Cacospongia. Some years ago, Geoff Avern, who was then a postgraduate student of mine, studied the growth of juvenile Noumea haliclona by carefully transferring the small juveniles on to new pieces of their food sponge every couple of days.

If you have photos of the larvae, the adults or the egg mass they would be interesting to put on the Sea Slug Forum. If you can't scan them yourself you could post me photos or slides and I will scan them here.
Best wishes.
Bill Rudman.

Dear Roberto,
From your earlier messages it seems you are making some progress. Hopefully someone can
give you advice. It seems you can keep the veliger larvae alive. Is your problem that you don't know how to get them to settle on to the substrate? .. Bill Rudman

Roberto,
I'm afraid you will need to consult one of the experts I suggested. I think most nudibranch larvae will eat a range of phytoplankton. What is important is which species of phytoplankton you can culture in your laboratory.

If anyone has any information or advice could you send a message to the Forum .. Bill Rudman.

Hopefully someone reading this will be able to help you.
I'm afraid I have never had the aquarium facilities necessary to keep larvae alive for more than a few days.
Steve Kempf at the University of Auburn http://www.auburn.edu/academic/science_math/biology/faculty/kempf.html has a lot of experience with larval culture.
The other person who has a vast experience with nudibranch larvae is Professor Michael Hadfield http://nic2.hawaii.edu/~zoology/faculty/hadfield.html.

One major problem is keeping the phytoplankton they feed on alive. There is an interesting website Reef Aquarium Farming News with information on growing phytoplankton.

I hope this helps. .. Bill Rudman.