Raising Brine Shrimp Outdoors
by Gary Sutcliffe, WAKO
Brine shrimp are a staple food for tropical fish. Although hatching baby brine shrimp is a daily practice for most fish breeders, adult brine shrimp are usually purchased from local pet shops in either live, frozen or freeze dried form.
Unfortunately I live about a half-hour drive from the nearest pet shop that stocks live adult brine shrimp. That is why I was especially interested when Greg Schoenburg mentioned the results he had raising brine shrimp to adult size outdoors. Greg raised up baby brine shrimp to adult size in about 3 weeks on the green water that he let develop in the outside 10 gallon tanks.
I wanted to do it on a somewhat larger scale. I have had excellent results raising daphnia in 4 foot diameter childrens wading pools. They have a lot of surface area and are inexpensive. I usually pay about $8 for them, but you can sometimes get them for even less at the end of the summer. They are also very rugged. I just let them freeze up during the winter, and the daphnia re-appears in the spring. They usually last about 5 years with this treatment.
I started out in June by placing a new pool in a sunny location, filling it up with water, and adding salt until the specific gravity reached approximately 1.020. That takes lot of salt! I used solar salt, which is sold for water softeners. I also added a couple of cups of baking soda and Epsom salts.
As part of my daphnia raising routine, I keep a 5 gallon plastic bucket in the sun to raise extra green water. About once a week I distribute about ? of the bucket among the daphnia pools. I then add about ? teaspoon of Miracle Grow fertilizer and refill the bucket up with tap water. I poured some of the green water into the pool to get it going. I was not sure if the green water would survive in the brine, but figured the shrimp would filter it out and eat it before it died.
After Greg collected the baby brine shrimp for raising fry, he poured the remaining water into his outside tanks. Typically there would still be dozens of shrimp left. Adding more every few days would ensure a continuos supply of smaller shrimp to replace the larger ones as they were collected. I thought this was a great idea and used it myself.
The brine shrimp are very difficult to see at first. Once they lose their orange color they blend into the water very well. Unless you look very closely, you may think they are gone. Once they start getting some size to them, they become easier to see.
The shrimp were growing and could be seen again when the first problem with the wading pool became evident. Then we had about 4 of rain in a couple of days. The wading pool is only about 6 deep. Adding 4 of rainwater on top of that meant that it overflowed, and greatly diluted the salt content. The shrimp disappeared.
I was pretty disappointed in all this and it just sat there for a couple of weeks. At that point I noticed that the bottom and sides of the pool were getting green. I added salt to bring the salinity back up, and put more newly hatched brine shrimp into the pool. Brine shrimp seem to scrape algae off the bottom when there is not enough to eat from filtering the water. About 3 weeks later the pool was swarming with adult brine shrimp!
I continued harvesting adult shrimp and adding baby shrimp through out August and September of 2004. My fish fed heavily on live brine shrimp during this period of best production. Production seemed to be steadier than with daphnia, which tend to go through bloom and crash cycles. Adding additional shrimp from your hatchery on a regular basis means you dont have to depend on them reproducing to keep the supply going.
As the water got cooler the shrimp seemed to stop growing, but continued to live. I harvested them until about the end of October when I had pretty much cleaned out the pool.
As the weather got cooler I noticed a build up of brine shrimp eggs at the edges. They were laying eggs. Eventually it got cold enough and the pool froze. It will be interesting to see if the brine shrimp reappear in the spring as my daphnia do.
I mentioned the problem with the wading pools when it rained. I also found another problem with them. Frogs are frequent visitors to my daphnia pools. They also decided to visit the shrimp pool. They are apparently not smart enough to realize this is salt water, and salt water kills them. I pulled several dead frogs out of the pool during the course of the season.
There are a number of things I plan to do differently this spring. First I am going to use different containers. If I find some, I would like to try some cut down plastic 55 gallon barrels. Failing that I will probably buy some plastic trash barrels. I hope to find something that has a large surface area but around 18 deep. This will reduce dilution if we get heavy rains. I also plan to put some sort of screen cover to keep the frogs out. A couple of the dead frogs were tree frogs, so just increasing the height wont keep them out.
I plan to set up earlier this year. The shrimp dont seem to grow much in cool weather, but I hope to use this time to get the algae going so when I do add shrimp they will have plenty to eat.
While I had a bit of a bad start, I believe raising brine shrimp outside is a viable process. Im sure that I will learn a lot more this upcoming season. If you decide to give it a try, let us know how it goes.