Blue Crabs (Callinectes sapidus) in Freshwater Springs

Marjorie Rawlings owned an orange grove in north central Florida from 1928-1941.  She was not a native southerner but used inheritance money to purchase the property.  Many of the characters she created in her short stories and novels were based on the people she met while she lived here.  Her most famous work is The Yearling, a novel later adapted for the big screen.  I think her most interesting book is her memoir of the 13 years she lived in a farm house next to her orange grove.  The title of this memoir is Cross Creek.  The relationships she developed with the “colored help” and the white “crackers” are entertaining reading.  Though progressive for her time, she clearly viewed black people as 2nd class citizens.  On 1 occasion she spent a week long hunting trip with her visiting brother.  When she returned to the farm she was outraged to discover the live-in “colored” help had spent the week enjoying a drunken orgy (literally…2 men and 1 woman in the same bed) and not a single chore had been completed.  Her brother joined her in chasing the help off the property at the point of a shotgun.  In my opinion Rawlings was at fault for being out hunting instead of supervising.  Moreover, today, her actions would be considered an illegal eviction, and she and her brother could be jailed for making terroristic threats.  However, if I could journey to 1930s Florida in a time machine and suggest this, all the white people there would think I was out of my mind.  How times have changed.

Marjorie Kinnan Rawlings with her dog - Cross Creek, Florida

Marjorie Rawlings, author of the famous novel–The Yearling.  This dog was accidentally poisoned.  She accused her neighbor of deliberately poisoning her dog, a charge he vehemently denied.  They feuded for a year before reconciling.

My favorite chapter in Cross Creek chronicled the local cuisine.  Bread here meant cornbread, cornpone, hoecakes, hushpuppies, or biscuits.  Meat meant salt pork, known here as “white bacon.”  Pork in 1930s America was much fattier than modern day pork.  White bacon was soaked in water, floured and fried.  The grease rendered from frying the fatty pork was used to season biscuits, cornpone, sweet potatoes, black-eyed peas, green beans, and greens.  These were the staple dishes but hunting and fishing supplemented the local diet with many exotic sources of protein such as alligator, rattlesnake, turtles and their eggs, limpkin, blackbirds, bear, and squirrel.  Rawlings accompanied men who went crabbing at night.  They caught crabs from a freshwater spring that flowed into the St. John’s River.  The men stood on boats and located crabs by shining lights into the clear water.  They used 12 foot poles with iron jaws on the end to snatch the crabs.

Crab

Blue Crab in Crystal River Spring, Florida. It’s probably a male.  The females stay in brackish water and migrate to waters with high salinity to release their eggs.

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Blue crab life cycle.

I was surprised to learn that blue crabs inhabit freshwater.  Apparently, during spring male blue crabs migrate in enormous numbers to brackish and fresh water.  During mating season the 2 sexes meet in brackish water to mate, and the females carry their fertilized eggs back to the saltier depths.  The larval stage of the blue crab is known as a zoeal.  As the zoeal grows, they shed their shells 7 times in a process known as molting.  Their bodies absorb calcium from the sea water and swell, and this extra calcium forms a hard exoskeleton.  Blue crabs are called megalops during the next stage of their life when  they move into water with lower salinity where they eventually transform into adult crabs.

Blue crabs outcompete and drive away crayfish in the freshwater springs they inhabit.  Both species eat the same foods, scavenging and actively hunting plant and animal material.  Blue crab larva can’t survive in freshwater.  If this species ever evolved that ability, they would eventually colonize freshwater creeks and rivers, causing a decline in crayfish abundance and diversity.  Fossil remains of the Callinectes genus date to about 15 million years ago, and Pleistocene-aged blue crab shells have been found from Massachusetts to the Caribbean and Texas.  It is an incredibly successful species.

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