Merck Grant Funds Gehnrich Crab Research"  

SALISBURY, MD---It’s the end of September, and every relative you know is descending on your backyard for the annual family reunion.  The hue and cry of the crowd is for that great Eastern Shore delicacy, the blue crab.  They want soft crab sandwiches, steamed hard crabs—crabs any way you can eat them.  But it’s the end of the crab season, and six dozen of them would be a major financial investment, if you could still find them. 

This scenario could change in the future, however, thanks to the research of Dr. Stephen Gehnrich at the Richard A. Henson School of Science and Technology, Salisbury University, Salisbury, MD. 

Gehnrich is studying the process by which the soft-shelled blue crab hardens its shell, specifically to identify the role of carbonic anhydrase, an important enzyme in the mineralization process. 

The crab’s molt cycle is an amazing creation of nature that has been observed by man for centuries but has never been understood.  The process of combining calcium carbonate, protein and chitin to gradually harden the new shell is a part of the ongoing growth process. As the crab gets ready to molt, it is at the same time preparing another shell underneath the hard one.  Just before it molts, losing the hard shell, it draws the calcium out of the old shell and stores some of it for hardening the new shell.  Each time the crab molts, it grows another inch, until it reaches maturity. It’s in this last molting stage that Gehnrich’s research could have the greatest effect. 

What could this research mean to the seafood industry?  An understanding of the biochemistry of the hardening process may one day enable us to inhibit the calcification of the shell so that we can keep soft crabs alive and unable to harden while being shipped around the world.  The seafood industry would be revolutionized with broadened international markets as the shelf life of the crabs is extended.  

The economics of supply-and-demand could be affected, as well.  The availability of soft or hard crabs could be controlled by delaying their hardening in tanks, and then stimulating them to harden when demand warrants. 

It may even be possible in the future to extend the mating season of these soft shell crabs and increase the supply.  When the crab reaches maturity, the female typically does not mate again after she sheds her last hard shell.  By delaying the last molting, she may be more productive.  

Those dreams become closer to reality as Gehnrich studies the enzyme’s molecular structure, learning more about the gene that makes it.  He began his study of shore crabs off the coast of Maine in 1999, but, since molting blue crabs are not found there, he continued his research on the Eastern Shore of Maryland.

His research at Salisbury University is made possible by a three-year grant of $20,000 each year , a joint effort of Merck Pharmaceuticals and The American Association for the Advancement of Science.  This is one of ten different grants Merck makes available each year to undergraduate studies. 

A grant from the Maryland Sea Grant College provided for the purchase of a thermal cycler, a machine that creates a chain reaction that makes millions of copies of the small pieces of blue crab DNA that Gehnrich wants to study.  This will make it possible for him to identify the DNA sequence of the carbonic anhydrase gene that causes the crab’s shell to harden.

At Salisbury State University some 6,400 students in 30 undergraduate and eight graduate programs pursue liberal arts and professional degrees. Located on the Eastern Shore of Maryland 30 miles from the Atlantic Ocean and 20 miles from the Chesapeake Bay, Salisbury is 2 ½ hours from Baltimore, Washington, D.C., Norfolk, VA, and Wilmington, DE. Princeton Review ranks SSU as on the top universities in the nation.