October 17, 2000
From: Bill Rudman
I have been asked quite regularly about how to culture larvae, and if it possible to just 'let nature take its course" when egg ribbons are laid in aquaria. I have just come across a paper on the culturing of Sea Hares in an aquarium from the egg, through the veliger larval stages, to metamorphosis and settlement. The methods and equipment required are clearly described.
Reference: Paige, J.A. (1986) The laboratory culture of two Aplysiids Aplysia brasiliana Rang, 1828 and Bursatella leachi plei (Rang, 1828) (Gastropoda: Opisthobranchia) in artificial seawater. The Veliger, 29(1): 64-69.
January 18, 2000
From: Karen Whiteid
My son is preparing a report on sea slugs. We cannot find information to tell us what the length of the incubation period for the eggs. Would someone let us know?
email@example.comWhiteid, K., 2000 (Jan 18) Incubation of eggs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1737
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,
August 4, 1999
From: Caroline Bodenham
I am from the Central West College of TAFE in Geraldton, Western Australia, and in our Aquaculture course we have been trying to breed nudibranchs from wild stock caught from local reefs. The adults laid eggs as soon as they were put into the aquariums, and eggs hatched successfully. We observed larva for aproximatly two months, within various substrates provided for them, and some even got through into our biofilter. We also placed plates in the tanks to encourage the growth of diatoms for the larvae to feed on. Suddenly, after watching them for weeks, they all disappeared within a couple of days!! Does anybody have any ideas as to what may have happened?
Geraldton is situated about half way up the W.A. coast in a mediterranian climate. Our shores recieve warm water from the Leeuwin Current comming south from the equator. Because of this current coral reefs and ecosystems survive here, and further south, where corals should not be. Our waters are very rich in sea life of all kinds from the warmer tropical species, to dugongs and porpoises, to the migrating whales, and Western Rock Lobsters which we export.
firstname.lastname@example.orgBodenham, C., 1999 (Aug 4) Nudibranch breeding. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1139
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.
December 19, 1998
From: Roberto Moresco
Larval stage of Hypselodoris tricolor in laboratory is about 25 days, and the larvae continue eating Tetraselmis and Monocrisis. Hatching occurs after about 10 days. Intracapsular moving starts after after abaut 8 days.
We have some problems with protozoa even if we use sterile water (U.V.), because we take egg mass by pseudo natural system into which we leave the sponge Cacospongia (food of Hypselodoris).
We culture larvas in Capsule petri 50ml into which we put U.F.M.W. sponge as inducer, we don't use substratum because we are worried about problems with water quality.
Moresco@freeweb.amicus.itMoresco, R., 1998 (Dec 19) Re: Larvae of Hypselodoris tricolor. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/407
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.
November 20, 1998
From: Roberto Moresco
My name is Roberto Moresco and I 'm looking for culturing the Mediterranean doridacea Discodoris atromaculata and Hypselodoris tricolor . The food we use is phytoplankton (Monocrisis and Tetraselmis ). We are able to arrive to the larval development. Is there anyone who knows help me to arrive to Juveniles development?
Moresco@freeweb.amicus.itMoresco, R., 1998 (Nov 20) I need help with culturing larval nudibranchs. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/325
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
October 7, 1998
From: Moresco Roberto
many thanks for your answer. I would like to Know which phitoplancon species are good for Nudibranchia larval culturing (captivity).
Robymanu@amicus.itRoberto, M., 1998 (Oct 7) Phytoplankton for Nudibranch. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/249
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.
October 5, 1998
From: Roberto Moresco
I'm a student of Enviromental Marine Scienze University of Genova (Italy). I would like to Know any informations about Larval nudibranch culture in captivity, about feeding of them and culturing in tank.
via Capri 11 Genova Italy
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.Rudman, W.B., 1998 (Oct 5). Comment on nudibranch larval culture by Roberto Moresco . [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/245