Egg hatching observations

[AnotherKevin]

Some of our Opae Ula spawned recently, and we noticed a few interesting things:

1. Dropped eggs might still hatch

Our first shrimp to have babies carried the eggs for about a month, then dropped six of the eggs. We were curious to see if those eggs were still viable, so we sucked them up with a pipette and placed them in a small dish. Two days later, four of the six dropped eggs had hatched. The other two did not hatch. The ones which hatched were burgandy red colored; the ones which did not hatch stayed light pink.

2. Eggs' shapes change as they mature.

The eggs start out spherical but tend to become olive shaped close to hatching time, and two little dots become visible.

3. Larvae don't start floating immediately.

When larvae first hatch, they seem unable to swim, maybe because they're still stuck in the egg membrane or the glue which attaches the eggs to the mom's swimmerettes. They just stay on the ground near where they hatched. It's only about a day later that they start to swim and float around.

Does this match what other people are seeing?

[Varanus]

I've never seen the actual hatching, but it does indeed seem to take a long time for the larvae to get free of the egg membrane/glue. I once watched a female stand completely still (unusual for these shrimp) high on a rock, her abdomen raised as her babies thrashed about, trying to break free of her for a good half hour without success, at which point she seemed to give up for the time being and went back to foraging.

[Mustafa]

Great observations! I've observed the same, except that in my experience the hatched shrimp still hang from the mother for a while before they finally just swim freely. I've never seen them sit on the ground.