Clam Shrimp in a Desert Pool - Revisited

Large number of Clam Shrimp in the muddy water of the pool, with my finger for scale.

I made another trip out to the ephemeral desert pool where I found the Clam Shrimp. I was hoping to get more photos of them. This trip was on 2021-07-30, the day after my initial trip.

Quite a bit of the water had evaporated. The deepest parts of the pool were only a couple of inches deep, and most of it was much more shallow. The pool was swarming with Clam Shrimp on this visit. I’m guessing that was because the smaller volume of water had concentrated the Shrimp in a smaller volume.

The water was very muddy, but I was able to get some photos of the Clam Shrimp as they swam in the shallow edges of the pool.

Clam Shrimp in the water of the pool. In this photo, the shrimp appears to be sweeping its long legs around and under the twig.

I think some of the white specks on the twig in the photo below might be Clam Shrimp eggs, presumably deposited when the water level was higher.

Two Clam Shrimp in the murky water of the pool. The shrimp on the left-hand side of the photo has eggs. If you look along the edge of the twig that is emerging from the water, you can see some white dots on it. These look very similar to the eggs that the shrimp have inside their shells. I wonder if these dots on the twig are Clam Shrimp eggs.

I took a few of the Clam Shrimp and put them in my portable photo aquarium to try to get better pictures of them. They are such fascinating creatures.

Two Clam Shrimp. We’re looking down on the back of the left-most shrimp. The right-most shrimp is on its side, and it is curling its abdomen forward and out of its clam shell.

I’ve labeled a little bit of the anatomy from the photo above. Click on the image below to get a larger version if you’d like to read the labels better.

9 Two Clam Shrimp, with arrows and labels

Clam Shrimp, in photo aquarium. The ‘back’ of the Clam Shrimp is towards the bottom of the photo. You can see the black dot of an eye on the right-hand side of the creature. Just above that, you can see some of the shrimp’s legs extending out of the clam shell. The round objects in the bottom middle of the shrimp are eggs.

Clam Shrimp in photo aquarium. The head-end of the shrimp is towards the top of this photo. you can see that the shrimp has a large number of legs, most of which are inside of its ‘clam shell’.

I came back and visited this pool again four days later, on 2021-08-04. I found plenty of Tadpole Shrimp (Triops) and Spadefoot Toad tadpoles, but did not see any of the Clam Shrimp that had been so numerous previously.

Clam Shrimp and a Spadefoot Toad tadpole. In a temporary aquarium.

Where did they go? Had  the Triops and the Spadefoot Tadpoles grown large enough to eat the Clam Shrimp?

Were the shrimp hiding in the mud? Or had the Clam Shrimp simply finished breeding, and died?