Saturday, July 30, 2011

One crab, Two Crabs, Three Crabs MORE

This week at Piers Park in East Boston and Courageous Sailing Center in Charlestown we conducted a citizen scientist carb count. Both sites are dock sites without any shoreline/ beach access. To record our crab numbers, we used lobster traps, crab traps, and even fishing poles dropped right by the side of the dock.

At both sites the kids are very excited when they catch an animal. When we caught a crab, we first determined what species of crab it was; the most common crabs found at these sites are green crabs and red rock crabs. The next order of business is to find out whether the crab is a male or female. The harbor explorers turn the crab over so that its belly is showing and, by looking at its abdomen, determine whether the belly is rounded or triangular shaped. A rounded belly means that the crab is a female and the triangular shape is a male. The last thing we do is to measure the crab's size. This is determined by measuring the large shell called the carapace. The width and length can be determined using a ruler or other unit measuring device.

Other things that were recorded were environmental conditions such as weather, water depth, and tide height. The data that we record about these crabs is part of a citizen scientist project started by MIT to study the populations of certain invasive crabs and hopefully stop the spread of unwanted guests.

I would like to thank my fellow harbor explorers for there excellent crab catching abilities and cannot wait for next week when we record again!


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