Thursday, November 28, 2013

Giant Moon Jellyfish

I went on a jellyfish collecting trip recently. I was recommended to go to a dock on a river near where the ocean meets the sound. These places are good for comb jellies. I ended up finding two giant moon jellies in addition to several comb jellies.

The first moon jelly washed right up in one of the boat landings. I saw it and my jaw dropped. A second, and bigger one washed up about ten minutes later. Neither of them would fit into my five gallon bucket! I ended up getting them back to where we were staying in bags. We then put them in large plastic bins with extra water. The water was very cold that day, and their salinity was crazy. 1.018, which is very low. Moon Jellies are often seen out in the ocean, from my knowledge. This is the first time I have seen live Moon Jellies from the Atlantic Coast, in the wild, in years. 

I managed to get these jellies home and settled. They now reside in a 44 gallon pentagonal corner tank. As you may know, jellyfish don't generally do well in faceted tanks or ones with edges. These guys are so massive that they don't seem to care! I'm glad, because I don't have any other tank for them right now. I measured them and one is 14 inches and the other 10 inches across the bell. There are some bigger jellies out there, but these are giant, for what I have dealt with. 

They both look like female, because their oral arms are dotted with what look like planula. Moon jellyfish have their eggs fertilized, and then hold on to them until they develop into planula. Some other jellies do this, whereas some species let their eggs loose, to be fertilized in open water. The tank water is now full of these tiny specs (visible to the naked eye!). I took some and checked them out under. Y microscope. They definitely appear to be planula! There are tons of them too! I hope that they settle so I can have some polyps. I do have moon jelly polyps already, but I don't believe I have Atlantic Moon Jellyfish Polyps. Moon Jellies in the lower Atlantic are generally Aurelia marginallis.

This time of year is when Moon Jellies are in season. It appears that most of them show up pretty big though. I suppose late summer they will be smaller, but harder to find. Lion's Mane jellies are also making appearances, but I have seen none so far. 

Trying to Raise Lagoon Jellyfish Round II

So I'm giving a second try at raising Lagoon Jelly babies. They aren't hard to keep from juveniles to adults, the newborn ephyra are what are tricky. My problem was that the ephyra would not grow, and would just die after a few days. 

I talked to some jelly keepers and came up with some new methods of keeping the ephyra.

Method 1 ( failed method) 
I used a 500 ml glass graduated cylinder. This cylinder had a bubble tube circulating the water. Lighting came from a desk lamp with a compact fluorescent bulb in it. Water temp was at ambient, room temp likely. 

Method 2 (current try)
I'm using the same graduated cylinder. This time I have a 12" strip of 20,000 kelvin white LED lights attached to the top and sides. The cylinder is set in another aquarium which is at 80 degrees F. I change the water every day. The cylinder is sitting in a 44 gallon corner tank, which I later plan on putting cuttlefish in. A canister filter and 150 gallon protein skimmer is running. I just exchange water between the tank and the cylinder daily. My hope is that the heavy filtration removes the negatives, but allows the benefits of a cycling tank. It may simulate an ocean more closely than 500 ml of water.

The major things I was told to change were lighting and temp. I've kept Upside Down Jellyfish at room temp. and seen so adverse effects. For proper zooxanthellae growth, a temp of 80 F or above is preferred. Lagoon Jellyfish ephyra are born very small compared to Upside Down Jellyfish, so algae food is the most important, as they may be unable to catch Brine Shrimp efficiently. A desk lamp probably won't do it, but I figured I could improve on lighting when they got older. Now I've decided to go ahead an get the improved lighting. There is debate about whether LEDs can match good old fashion metal halide lighting. I think LEDs will do the job. I certainly hope so, as they are much more energy efficient, space efficient, and cooler. If this works out, I plan on buying longer strips of lighting. If not, I probably need to try metal halides. 
My current set up. The bright cylinder is where the lagoon ephyra are kept (3 of them right now). The plastic bottle is a brine shrimp hatchery. It's too cold in the garage for them to hatch in ambient temperature. The protein skimmer is also pictured. White light is coming from the LEDs and orange  light from the desk lamp. 

Results: the second set up has worked. The good temp, light and daily water changes seem to do it. I've raised two batches of lagoon jellies so far. The first batch of jellies tipped over though (oops! :p). The second batch is being raised now. I have 15 total ephyra. I'm hoping these will go to adults! More progress soon :)