Breeder's Net : Amazing Artemia!
One of the most interesting landmarks in the State of Utah is the Great Salt Lake. Tourists flock here in the summer, to test the buoyancy effect the high salinity level provides. Those of us who live here always find it interesting to see tourists voyage into the water, and the look on their faces is always amusing! Obviously, it is not what they expected.
The Great Salt Lake is what remains of a huge lake once known as Lake Bonneville. Over the millenniums, the water evaporated, leaving the salts behind and increasing the salinity of the water. As the salinity rose, the species of fish able to adapt to the elevating salt levels plummeted. Eventually, only one remained: Artemia. Not a fish at all, a crustacean. A shrimp, to be precise. Without any predators, this species has thrived.
Now, in 2008, this lake is in the midst of a large metropolitan area. The rain that feeds our lawns runs off into rivers that feed the lake, and the lake is high in nutrients from our lawn fertilizers. This environment, during the warm months, is a predator-less paradise where the artemia gorge on the abundant microalgae, grow rapidly and reproduce live nauplii. Because their diet is so abundant in various microalgae, their colors vary, ranging from dark to light red and green. When the cool weather begins, these shrimp begin producing cysts that are ready to hatch the next spring. The artemia then die, producing a stench smelled for miles. The brine shrimp eggs (or cysts) produced are large and abundant.
Hatching out the cysts
Techniques for hatching out these cysts vary. You can decapsulate the cysts (remove their shell) using a 1:3 part solution of FW and household bleach to remove the shell. Use a covered container to gently toss the eggs in the bleach solution and rinse well when they turn orange. I use a micro sieve to rinse them. You can use a spaghetti strainer lined with a coffee filter. These eggs are great to spot feed your corals, but will not hatch as easily. The shell is what creates their buoyancy.
I use a lot of artemia to feed my fry and my corals, so I do not go to the extra step of decapsulating. My fry are very discriminating about only eating motile food and I have not had an issue with shells. Some feel the extra step of decapsulating is worthwhile, so evaluation of your particular need is important.
I have tried a few commercially available hatcheries and the best I have tried thus far is the inverted 2 liter soda bottle. When cut in half and the top placed into the bottom, a vessel is created that encourages the heavier unhatched cysts to sink into a small area that houses a piece of rigid airline tubing. The rigid tubing is attached to a piece of flexible tubing to bring air from a small pump. Using a gentle flow, the air bubbles then lift the cyst up and into the water column. As the brine shrimp hatch, the empty shells float. After a day, I turn off the pump and wait a few minutes, then siphon the live brine shrimp from the bottom of the vessel, leaving the last inch of shells in the vessel to be rinsed into the sink.
When the cyst is newly hatched, and it has not yet consumed its egg sack, it does carry some nutrition. Some sources I have read say it is a few hours to up to a day. I have found it difficult to tell exactly when the cyst has hatched, thus making it difficult to say when the brine shrimp has lost its value. You can evaluate with a microscope, but that is a tedious step when I want to feed and go on with my life. So, I just enrich them. I look at these tiny napulii as a grocery sack, carrying the real nutrition into my aquatic home.
To enrich really means to gut load. I feed the nauplii the products I am trying to deliver to my tank: phytoplankton paste and concentrates; a fatty acid supplement, Selco; even medications or Betaglucan. Brine shrimp are filter feeders after their second molt so they will consume what ever is in their random path. According to Brine Shrimp Directs website, the fatty acid supplement Selco not only gets consumed, it "sticks" to the napulii. I keep the hatched artemia in a jar with an air line and just enough phyto paste to tint the water green for days. I use a turkey baster to feed a bit to my reef just before the lights go out. If you have a smaller tank, you may want to drain the water to avoid adding excess nutrients to your system.
I have found it possible (actually very easy) to have a continuous culture of brine shrimp. It takes around 2 weeks for a nauplii to grow into an adult. At that point, they produce live nauplii. I use a simple 2 gallon container. I feed just enough phytoplankton concentrate to keep the water tinged green. I place an airline in and a piece of macroalgae for filtration, and keep the culture in a brightly lit area. I harvest a cup a day, filtering the water out into the drain, and then releasing the live adults, almost adults and the napulii into my reef. The chase begins and the fish love it!
- I use old tank water from my last water change to hatch cysts. Room temp works great. If you fill the bottom of the 2 liter hatchery with hot water, you can hatch the batch quicker if you need BBS fast. Also, having the water weight in the bottom makes the hatchery much more stable.
- If you have multiple hatchers and grow out containers, using different colored tubing from your gang valve will make it easier to visualize which tube is going to which culture vessel. It is helpful when trying to adjust the bubbling to the proper flow. It is a necessary to find the right flow: too much flow will push the cysts out of the water; too little and the cysts sink to the sides of hatchery.
More information about these amazing shrimp can be found at: http://ut.water.usgs.gov/greatsaltlake/index.html