Host anemones- Sexual reproduction

[Flighty]

By popular request I'd like to kick off a discussion about sexual reproduction of host anemones.

Captive breeding- As far as I know it has been recently done once in Australia.

article here:
http://www.abc.net.au/news/newsitems/200504/s1339204.htm

Last Update: Wednesday, April 6, 2005. 10:25am (AEST)
Breeding first for sea anemones
Researchers at the National Marine Science Centre at Coffs Harbour, on the NSW mid-north coast, have bred sea anemones in captivity for the first time.

The project might help the long-term survival of sea anemones, which are in danger of being harvested to extinction in some areas to supply a thriving aquarium trade.

PhD student Anna Scott, who is heading up the project, says anemones reproduce by releasing sperm and eggs into the water.

"The males release these amazing clouds of milky white sperm into the sea water and with the water movement that disperses quite rapidly," she said.

"The females release large masses of eggs that are held together in a light mucous, and then they float to the water surface where they break apart."

She says her research might allow for commercial breeding in captivity.

"There's a definite possibility that the data from this research can be used to start mass culture techniques for host sea anemones, and with that we can then supply the aquarium trade with animals that have been bred in captivity, or we can replenish areas that we have already impacted," she said.

Surprisingly little is known about this topic, but think of how wonderful it would be to captive breed some of the more difficult anemones and take the strain of collection off of wild specimens.

Spawning in captivity- Does anyone have both a male and female of the same type in a tank?

It isn't even known if all of the host anemones release both eggs and sperm or if some are internally brooded.

 

[Flighty]

I have contacted the researcher mentioned in the above article, Anna Scott by email. She said her research has been on E. quadricolor and H. crispa so far and both used external fertilisation.

 

[bencozzy]

i believe RC member Anemone has a male-female of BTAs in his tank.

and as a note- i have had rock anemones spawn and produce young.

i syphoned off about 3/4 of the tank water into rubbermaid tubs and had air stone running on risers for circulation.

it took about 18hrs for the young to settle.

i then added algea with lots of pods to the tubs(i think now there are much better substitutes to live feed, i.e. cyclopeeze and ive noticed very small aiptasia will eat marc weiss's black powder).

i only had them for a week due to a power outage but in that time they tripled in size(from the size of a pencil eraser to about size of a nickle). and also i lost a few due to insuffient amounts of food.

FWIW

 

[Flighty]

A page about Anna Scott's research here:

http://www.nmsc.edu.au/Postgraduate area/Anna Scott research page.htm

SEXUAL REPRODUCTIVE BIOLOGY OF HOST SEA ANEMONES IN THE SOLITARY ISLANDS MARINE PARK, NORTHERN NSW

Host sea anemones are ecologically important species as they provide essential habitat for obligate symbiotic anemonefish and a range of other commensal organisms (Allen 1972, Shick 1991, Fautin and Allen 1992). The density of host sea anemones within the Solitary Islands Marine Park is the highest recorded anywhere in the world, with two species, Entacmaea quadricolor and Heteractis crispa known to occur (Richardson et al. 1997a).

Due to the fascinating symbiotic interactions between anemonefish and their host anemones, these animals are highly prized for the aquarium trade (Shick 1991, Fautin and Allen 1992). However, since the reproductive ecology of host sea anemones remains virtually unknown, collection for the aquarium trade relies on wild populations. This depletes local populations and potentially threatens their existence in some areas of the Indo-Pacific (Fautin and Allen 1992).

In order to address this lack of information, this research aims to provide the first quantitative data on the:

Ã"šÃ‚· Sexual reproduction

Ã"šÃ‚· Larval development

Ã"šÃ‚· Settlement and metamorphosis

of host sea anemones. These are critically important processes that renew and maintain populations of these important species.

Data from this research provide essential information for management of host sea anemones and their associated species, and could facilitate their mass culture. Mass culture has the potential to reduce collecting pressures on wild populations by supplying the aquarium trade with animals bred in captivity, and would also allow the restocking of anemones on reefs denuded by human and natural disturbances.

Publications

Scott A and Harrison PL (in press) Synchronous spawning of host sea anemones. Coral Reefs, Volume 24, Issue 2

Scott A and Harrison PL (2004) Spawning and early development of host sea anemones. 10th International Coral Reef Symposium, Okinawa, Japan, 28th June ââ"šÂ¬Ã¢â‚¬Å“ 2nd July (Abstract only).

Scott A (2003) Spawning and early development of host sea anemones in the Solitary Islands Marine Park, Northern NSW. Australian Coral Reef Society Conference, Townsville, Australia, 26-29th September (Abstract only).

Scott A and Harrison P (2003) Spawning of host sea anemones in the Solitary Islands Marine Park. Australian Marine Sciences Association Conference, 8-11th July (Abstract only).

Scott A (2001) The effect of elevated nutrients and reduced salinity on scleractinian coral reproductive success. Honours Thesis (1st Class), Southern Cross University, Lismore.
...

 

[Anemone]

http://www.advancedaquarist.com/issues/nov2002/feature.htm

Well down the page, under "Observations on Sexual Reproduction in Entacmaea and Stichodactyla." The Waikiki Aquarium has had sexual reproduction occur for a number of years, so I'm not sure about this new claim to be "first."

The RBTAs in my tank have spawned a couple of times, releasing eggs in much the way Anna Scott mentions (at the time, they were all female....I now have a male clone as well). However, DelBeek has observed egg-brooding and planulae release in E. quads in the Waikiki Aquarium.

FWIW,
Kevin

 

[Amphiprion]

If anyone else has a male H. crispa, I would be more than happy to rush some eggs from my female-I'd love to see captive reproduction of this anemone (especially for and by aquarists, not laboratories). The only problem is that I only get about, say, 12 hours notice before I know it is going to happen.

 

[Flighty]

I think they would need to be together to get the male to release sperm at the same time, right?

Anyone have a magnifica that has released eggs or sperm?

 

[BonsaiNut]

This is going to be a fun thread. We should probably start with:

1) Observation
2) Hypothesis development

So, for #1, for those of you who have experience with spawning anemones, could you post as much as possible about the spawning event, when/how it occurs, what the local conditions were, etc.

#2, if you have seen this occur more than once, what are thoughts you might have on what might trigger the event. Is the event preceded by environmental factors? If you have a very stable environment with frequent spawning, what is the spawning frequency?

And... a photo to get us going (larval tube anemone eating a larval shrimp)

 

[phender]

It seems odd that BTAs would both disperse and brood their eggs. Maybe they disperse eggs if their is no sperm present and brood the eggs if the sperm is present first.
From a culturing stand point, I would think that anemones that brood and spit out little babies would be ideal. S. gigantea does this, but their care requirements are too difficult. I wonder if S. haddoni are brooders also!
I know we are talking about sexual reproduction, but a year ago a guy said that his H. crispa had been assexually reproducing in his tank for some time by budding babies off its basal disk.
Here's a pic of a baby

Here's the adult

What do you folks think?

 

[Flighty]

If anyone else has a male H. crispa, I would be more than happy to rush some eggs from my female-I'd love to see captive reproduction of this anemone (especially for and by aquarists, not laboratories). The only problem is that I only get about, say, 12 hours notice before I know it is going to happen.

How do you know before it happens?

 

[Amphiprion]

Actually, (and I wouldnt believe it if I hadnt seen it) she does several things before she spawns. First, usually several days before (not always 100% indicator, though) she will eat less and regurgitate more, supposedly from reduced gastrovascular space. Also, she opens up less, usually much smaller for a day or so. Then, on the day it is to occur, her tentacles become short and stubby-not necessarily shrunken, but are probably equal in girth but mainly due to increased tentacle diameter. Finally, when the lights are turned off, she usually "balls up" and retracts (but not always) and BURP-voila instant eggs. Sometimes there is a great abundance of follicle cells-like this last time-and other times the water may stay 100% clear. You mentioned earlier that both would have to spawn at the same time- I think, just a guess, that if egg material or some follicle cell-laden water is added to another tank, it would probably induce spawning.

 

[Dwayne]

Here are some oics of H.crispa releasing sperm into the tank. The event has happened several times after the times mentioned here.

 

[Amphiprion]

Awesome. I think the earliest mine did it was in '98-not sure though, did not really keep track of it then. BTW, Diver Dan is a brave man getting that close to a sea anemone.

 

[Clarkii Clowns]

Is splitting concidered reporduction ?

I thought it was a sign of growth and not reproduction even though you actually have two after the event.

 

[bencozzy]

splitting is considered growth.

 

[Flighty]

Is splitting concidered reporduction ?

I thought it was a sign of growth and not reproduction even though you actually have two after the event.

It depends on the context. Splitting is asexual reproduction, but is also called growth in some applications.

 

[RustySnail]

I have a Mertensii carpet that is spawning. There is a second carpet anemone in the tank, but I'm not sure if it is also a Mertensii or not. Currently the anemone is raised up from the sandbed in a bowl shape with clumps and clouds of sperm slowly being released. The tankwater is slowly getting more cloudy (150g tank). The second anemone is looking strange; somewhat closed up around the edges (looks 'disturbed', but not bad). The pattern of the tentacles on the non-spawning anemone is very similar to the Mertensii; so it is possible that they are the same species (except that the non-spawning carpet is blue, not green).

My biggest concern is over water quality; does anyone know if the spawning can cause a tank crash condition? I am mixing up 30g of SW and have 30 more waiting just in case...

 

[traveller7]

RustySnail,

Grab some pictures, ID sounds interesting.

Most spawns send the skimmer into fits, but the tank settles down within 24 hours. I have only had problems when a tank was way overstocked, if yours has a heavy bioload, a 20% waterchange shouldnt hurt.

 

[Gary Majchrzak]

Pics of my Macrodactyla doreensis spawning. The event lasted over 45 minutes. My skimmer got really active, and I lost over 4 gallons of water. I'm not sure if there was a "trigger" for this event.

Another picture of the same event. Note Saddleback gut full of anemone eggs!

 

[Flighty]

Bump. I am trying to get more info on this subject.