Bivalve larvae

[FuEl]

Hmm..was just thinking if bivalve larvae could be used as first foods for baby seahorses/corals, etc. Just thought some of you guys could try it out. I know they use bivalve larvae (trocophore stage) to feed grouper larvae.

Bivalves spawn during

1)Temperature shock (Eg. fresh temperate oysters dumped into 28 degrees water)

2)Lowering of salinity (More oftenly used for tropical species)

3)Chemical induction using strip spawning (manually strip spawn a male and release the gametes into the water to induce mass spawning)

4)Serotonin injection into gonad.(used for bigger species like tridacna clams whereby gonad is easily accessible).

Once they spawn, separate the oysters into individual chinese food containers to collect the eggs or sperm. The solution of eggs and sperm will look very different.

You should try to keep things as hygienic as possible (Eg. U.V treated seawater, filtering of fertilized eggs later on)

Mix a little sperm with the eggs. The amount to add can be found in bivalve literature. If you want to try by trial and error also can. Then leave the fertilized eggs in large containers with gentle aeration. 24 hours later they should start swimming, and can be gutloaded with the appropriate microalgae or just fed directly. Oh yes, 24 hours after fertilization they can be collected using a 25 micrometer sieve.

Species that can be considered to produce larvae..hmm..not so sure for aquariums. Maybe large squamosas? Or maybe even cockles.

[blueheaven]

But won't it pollute the tank?

Was considering culturing clams though

[FuEl]

But won't it pollute the tank?

Was considering culturing clams though

? Live larvae won't pollute tanks unless they die.

[FuEl]

Asked my lecturer about this today. He said bivalve trochophores and D-veliger stage larvae are commonly used to feed crustacean and even fish larvae! Their nutritional composition is better compared to rotifers...and they are supposedly smaller than rotifers. Trochophores do not need enriching..they develop from fertilized eggs about 12-15 hrs later. D-veliger stage occurs at about 24 hrs post fertilization. Might give better survival if fed in conjunction with rotifers during early larval stage as it might offsets the lower nutritional composition of Artemia during transition phase. Oysters, mussels, etc produce eggs around 50-70 micrometers..giant clams around 100-120 microns..maybe T.squamosa somewhere in between? Replacement for copepods if you cant culture them in sufficient amounts!

[bawater]

Too big & too expensive, you will find commercial hatcheries will try to keep cost low. 50ml of live D-veliger frozen in liquid nitrogen cost a bomb to buy-

Even home aquarist would want to.

Food fish larvae are usually large, those that are smaller are fed rotifers & weaned onto bbs. The industry is looking at alternatives to bbs due the limited harvest and rising prices. But rotifer growing is pretty standard practice.

If we are looking at aquarium fish - those with big fry & egg layers can be started on rotifers(enriched accordingly for larvae development).

Those lavae with pelagic stages are the difficult ones - & can be raised on copepod nauplii and small strains or baby rotifers) . First foods need to be smaller than 50microns. Somewhere around 10microns - 20 - 30 micron size.

The first food availability is where the major losses occur.

[FuEl]

Too big & too expensive, you will find commercial hatcheries will try to keep cost low. 50ml of live D-veliger frozen in liquid nitrogen cost a bomb to buy-

Even home aquarist would want to.

Food fish larvae are usually large, those that are smaller are fed rotifers & weaned onto bbs. The industry is looking at alternatives to bbs due the limited harvest and rising prices. But rotifer growing is pretty standard practice.

If we are looking at aquarium fish - those with big fry & egg layers can be started on rotifers(enriched accordingly for larvae development).

Those lavae with pelagic stages are the difficult ones - & can be raised on copepod nauplii and small strains or baby rotifers) . First foods need to be smaller than 50microns. Somewhere around 10microns - 20 - 30 micron size.

The first food availability is where the major losses occur.

Hmmm...I agree with your point. Just wondering if anyone in Sg has tried spawning bivalves to produce live feeds? If people have witnessed their Tridacna clams spawning in their tanks..It might be possible to do so for cockles,mussels and clams meant for consumption? The larvae can then be supplied either fresh or frozen to either fish larvae in the appropriate stages or even to corals like sps. Does'nt hurt to have more variety does it?

bawater..you studied aquaculture too?

[bawater]

nope, hobby study more like cause the practical is fun.

with little methods released for ornamental culture - i turned to finfish/foodfish culture methods then shrink down operations/designs for me wif no space & hobby tools. .Just for fun, some work some don't. I'm looking more on the nutrition and larvae development on foods- i think this is a vital key in mortality.

But try to only look at inland aquaculture(closed systems)- that's more like the difficulties like what the hobbyist will face.

Giving on average - a hobbyist will have abt 3-4 sq foot of space and about 3hrs a day to run cultures/raise larvae. If you can make a production model of the bivalve culture out of a standard 2ft tank!why not - that's an idea .

The yeild would definitely be enough for home usage.Then we have to look at the nutritional value if used for larvae.

Running a 2ft culture of rotifers produces a hell of a lot - then enriching them on specific EPA/DHA profiles , you can customize them.hee hee,but this only last 1-2 weeks then have to do the same to 1 day old bbs.

[FuEl]

It would not be impossible set up a protocol for hobbyists to set up bivalve cultures. I doubt we would need to do any enriching as trochophores and D-veliger stage larvae should be nutritious enough. The problem is getting the correct species and the correct stimulus to induce them to spawn. I've only worked with sydney rock oysters so far and as this is a temperate species they spawn immediately once u place them in warmer water. Another factor is to know when their reproductive season is as you will not want to waste time conditioning broodstock to breeding condition.

It's impractical to use temperate species as a continuous source of larvae as the shipping costs each time will kill you financially. You might however, be able to ask certain seafood joints to bring in ripe oysters for you. Tropical species that might be worth a try could be mussels, market clams and maybe cheap Tridacna clams if you can smuggle them over from Indonesia . One of the latest spawning induction techniques involve the use of U.V irradiated seawater. Sounds rather promising for home hobbyists. Perhaps this in combination with a salinity drop might induce them spawn on command.

Probably will need a decent microscope to add sperm to egg in a 3:1 ratio. Then just leave it under very very gentle aeration for 12 hrs and you get trochophores.

Might seem more troublesome than rotifers..but it does spare you the time spent on enrichment.