Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

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click for a larger view of the blue crab - photo left -photo right

The Beautiful Swimmer - The Blue Crab

With a maelstrom of four grandsons running around in all directions over the holidays we had a wonderful time chasing critters. Isn't it interesting how humans have the propensity to catch live things? Even in modern times when we try to be more non-consumptive of wild creatures, we engage in activities such as bird watching & listing which clearly reflect this same tendency- to chase and collect the way our ancestors had to for their survival.

One of the many fascinating critters caught at our dock on Lemon Bay was a magnificent male blue crab (see attached photos). The males are larger, presumably for combat for territory and females, and can be easily identified by the narrow strip on the abdomen (which is tucked under the carapace which is the head and thorax combined). Females have a broad abdominal "apron" instead which is used to hold the eggs. Note the proper technique to hold a crab to avoid being nailed by the huge claws. This particular male was huge, which is surprising in this location since the largest crabs are generally found in the lowest salinities, such as in Chesapeake Bay. This is a swimming crab, unlike the local stone crab which is a bottom walker. You can tell a swimmer by the rear-most leg which is a flipper; it is remarkable how adroitly these crabs can swim sideways with such a small appendage. An interesting factoid- blue crabs have two equal-sized large claws whereas many other crabs have only one large one- why do you suppose that is? Note also the shape of the shell with two spines at either side- presumably to choke a predator trying to swallow them.

The blue crab is of course a great delicacy as food and is avidly pursued by many creatures. Not surprisingly, crab populations are at a low ebb in most locations due to overfishing as well as habitat degradation. It well illustrates a problem recognized by early English law-makers as the "Tragedy of the Commons," namely the universal over-utilization of resources held in common for all people but not well regulated by law. Who will be altruistic and leave a crab in the sea if someone else will soon come along and catch it? It is a tribute to the tenacity of the blue crab that it has for so long survived this onslaught. So let us salute the magnificent blue crab and vow to eat fewer of them in the future.

Bill Dunson
Englewood, FL & Galax, VA