Do It Yourself Aquaculture Fish Farming - Managing The Ova And Alevins

Should you buy eyed ova or harvest your own? How do I take care of the ova and what do they need? What are alevins and what do I do with them? All good questions for the novice aquaculturist to ask. Those tiny little eggs seem so fragile, don't they? They are, but you can handle them with a little guidance.

For the do-it-yourself aquaculturist with a stock of eyed ovum, it's time to really get going. The rearing boxes need to already be resting in the ponds for several weeks before the ova are ready. The edges of the boxes will be about 6 inches above the water and the box itself is moored so it won't budge.

Now it's time to suspend the hatching trays. The trays are hung inside the rearing boxes with the h2o level coming up to the top edge. This is where your ova will be calling home until they hatch and are hearty enough to swim out into the rearing box.

The ova will need to be carefully washed before they can be added to the hatching container. The technique for washing the ova is quite simple. A large container is filled with water and ova, the water is drained off and clean water added. This process is repeated until the water runs clear.

After washing, the ova can be placed on the hatching trays. This can be done by tenderly ladeling the ova, a few at a time, out of the washing container. Hold the ladel very close to the tray and empty the ova as gently as possible. Never pour the ova from a height, the impact will certainly kill them.

Ova will hatch at a far higher rate if they are spread into a single layer. This is a very delicate procedure and requires a gentle touch. A feather is just the right tool for the job. Gently running the feather over the ova will spread them out with minimal damage.

Despite taking all the necessary precautions, some of the ova will not make it. They can be easily ID'd by their white or opaque color. Dead eggs must be discarded from the hatching trays immediately. Leaving them in the trays can lead to fungus growth that can ruin your entire brood.

A natural way to clean out dead ova is to introduce fresh-water shrimps to your hatching trays. They will only eat the dead ova and will not damage live ones. These mini aquaculture housekeepers will clean out animal and plant debris in the water as well.

Keeping a lid over the rearing boxes will also help to protect ova from fungus growth. Fungus loves light and a lid will cut off the light and keep growth down. A lid is also a great way to protect ova and young fish from predators.

In a short time, the first fish will begin to hatch. These young fish, known as an alevin, will have a large bag on their underside. This is the yolk sac. The fish will require no food to start with. They'll feed off of their sac for the next month and a half or so.

Eventually, the do-it-yourself fish farmer will find out that some of his alevins have started to move away from the rest at the bottom of the hatching trays. They'll start to swim up against the current. Now is the time to begin feeding them finely processed meals. Their yolk sacs are nearly gone now and they are moving on to the next stage of their lives.

In the next article of this series, we'll investigate the "fry" stage of fish and the steps the do-it-yourself aquaculturist does to ensure their health.

Until next time...