Tuesday, July 26, 2011

One Crab, Two Crab, Red Crab, Green Crab!

I am no stranger to crab counting. In fact, one of my first jobs was as a research assistant counting Asian shore crabs on the beaches of New Hampshire. So naturally, I was very excited today to conduct one of our first crab counts of the summer at Blacks Creek in Quincy.

We started by surveying the area and writing down our observations. Then the kids made a prediction about the kinds of crabs they thought we would find.

This explorer's prediction was exactly 7 green crabs

After a very thorough survey, we found 4 green crabs over the course of the morning. Interestingly, they were all males. After some discussion, we came up with a possible explanation, that male crabs might come in closer to shore and be easier to catch than females, or maybe there are just more male crabs at Blacks Creek! It will be interesting to see what the rest of our crab counts reveal.

The explorers also theorized that reason we didn't find any red rock crabs was that the rocks around Blacks Creek aren't big enough for these crabs to hide under. We're not sure yet why we didn't see any Asisan shore crabs, but we did talk about how it's a good thing that this invasive species hadn't yet taken over at this location!

We'll be conducting crab counts every week at almost all of our sites for the rest of the summer. The results will go to Dr. Judy Pederson at MIT to be used for her research on invasive species. So far, the Boston Harbor Explorers seem to be having a great time searching for crabs and helping out science!


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