Is that Orzo?

I know that this is the middle of August, but I’ve been sitting on this way too long.

Back in March, I noticed a pinkish blob at the edge of the pavement as I drove down into Explore the Wild. It was morning and it had rained heavily the night before. As I passed the pink blob I slowed to have a closer at it. The blob appeared as though it might be a small pile of some sort of wet seeds, or cooked orzo. The water of the Wetlands was some five feet away.

A clump of cooked “orzo” at the edge of the Wetlands.

On the other side of the pavement was a partially crushed crawfish. It was fresh and appeared to have recently been run over by a vehicle. There were a few pieces of “orzo” in the vicinity of the crawfish. Turning the crawfish over I noticed some of the wet pasta on the underside of its abdomen.

“I’d better put on my glasses.”

Going back to the other side of the pavement, to the pink blob, I took a much closer look at the rice shaped objects in the pile. Some of them were moving. It wasn’t pasta, it was a pile of baby crawfish!

One of the many newly hatched crawfish with its siblings.

This was definitely something new for the Wetlands, and another mystery to ponder.

That’s a dime the crawfish is standing next to.

I wasn’t the only one that noticed the crawfish.

A large red ant drags away two of the little decapods, who, like pasta left too long in a colander, are stuck together.

What had happened here? I couldn’t quite read the signs laid out in front of me. There was a pile of a hundred, maybe two hundred, tiny crawfish on one side of the pavement. There was an adult with a half dozen or so tiny crawfish stuck to her abdomen, or scattered around her, on the other side of the pavement. The two obviously had something to do with one another, but what.

I know that crawfish carry their eggs on the underside of their abdomens. When the eggs hatch the miniature crawfish usually cling to the mother for several days but later fall off into the water to fend for themselves. This all takes place in the water.

If a raccoon had taken the crawfish from the water it would most certainly have eaten the little crawdads, they must be quite tasty considering their parent’s sweet tasting flesh. Imagine, a handful of tiny crawfish, soft-shelled crawfish at that! A raccoon couldn’t pass that up.

No, it wasn’t a raccoon that caused this. Quite simply, there would be nothing left of the little crawpups had it been a raccoon at work here. It must have been a vehicle. I’ll probably never figure out for certain, though, how the pups ended up on one side of the path and the adult on the other. Maybe the mother jettisoned the whole mass out of shock when a vehicle rounded the corner, surprising her as she walked. She then continued across the path and was hit as the vehicle later returned (there’s only one way in or out of Explore the Wild with a vehicle).

These crawfish seem fearless to me, so I doubt that’s what happened. She would have stood her ground and protected her young. The bigger question is, why was she walking along the pavement with an abdomen full of young crawfish in the first place? The truth will most likely remain a mystery.

I was able to save many of the young by picking them up and placing them in the water. They would have surely dried up, been carried away by ants or some other insect, or even stepped on if left where they were.

Should I have saved the young crawfish? After all they’re not native to our area. These large crayfish appear to be Red Swamp Crayfish, or Louisiana Crayfish (Procambarus clarkii), which are native to NE Mexico and South-central US.

How did they enter our Wetlands? Don’t know for sure (I have a secret theory). But the truth is that they could have gotten into our Wetlands in a number of ways; walked upstream after being discarded by someone along Ellerbee Creek which is where our Wetlands’ water empties into, dumped from an aquarium in one of the neighborhoods above us and later washed into the Wetlands after a heavy rain event, or placed in the Wetlands directly by some well meaning citizen.

Friend or foe?

However they got here, they got here. They’re a food source for frogs, snakes, herons, grebes, mergansers, and when they’re little like the “orzo” babies above they nourish water scorpions, dragonfly nymphs, larval predaceous diving beetles, small frogs and snakes, and a host of other creatures that live in and around our Wetland. I’m quite sure that the Yellow-crowned Night Heron that was, and may still be, with us this summer stayed here for the tasty crawfish that are walking and swimming around our Wetlands. It looks as though the presence of the crawfish has benefited at least some of the other wildlife in the Wetlands.

A word of caution though, read this from the Invasive Species Specialist Group’s (ISSG) Global Invasive Species Database regarding our friends:

“Its introduction may cause dramatic changes in native plant and animal communities…alter water quality and sediment characteristics…and reduce populations of invertebrates, mollusks, and amphibians through predation and competition.”

There is much information available at the ISSG site, check it out.

Is this crawfish the reason I’ve been seeing fewer young Green Treefrogs in the vegetation surrounding the Wetlands this season? Could the Red Swamp Crayfish be causing the vegetational changes that seem to be taking place in our little swamp? I’ve noticed that there are far fewer submergent or floating plant species in the Wetlands than in previous seasons. Is the crawfish responsible for these apparent changes?


8 responses to Is that Orzo?

  1. Kristin says:

    I just read this, that is SO cool. Wish I had seen it, I’ll keep my eyes open!

    • Greg Dodge says:

      It is cool. But I still wonder exactly what happened that morning, why the hatchlings ended up on one side of the path and the adult the other.

  2. jennifer says:

    Thanks for the science mystery theatre and for the cautionary words about invasives!

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