Monday, May 20, 2024

Soft Shell Crabs Explained

 Lennie Frosch, a native of Mandeville, spoke to the Northlake Mandeville Rotary Club 48 years ago about the intricacies of crabbing in Lake Pontchartrain. It was a detailed and comprehensive overview of the longtime area activity. Here is the article that appeared in the St. Tammany News Banner regarding that presentation. 


Click on the above image to make it larger. 

Below are excerpts from that article:

ST TAMMANY NEWS-BANNER, September 1, 1976

At the time Frosch served as Vice-President of the St. Tammany Parish Library Board and also as Chief of the Mandeville Fire Department. Frosch talked to the Rotarians about his hobby, Lake Pontchartrain crabs.

Frosch told the Rotarians that the conservation department and all its studies and surveys actually has very little information available about crabs. He noted that for some reason Lake Pontchartrain crabs seem to be superior to crabs caught along the Gulf Coast of Louisiana and Mississippi and crabs from Mandeville seem to have high priority in the seafood market.

Frosch noted these various statistics: the average life span of a crab is three years; crabs mate in Lake Pontchartrain, but the females spawn in the saltier waters toward the Gulf of Mexico; a bearer or sponge crab is usually the reference made to a female crab carrying eggs on her underside; a female crab carries as many as 700,000 to 2,000,000 eggs from two to nine months after mating. She then goes into the salt waters of the Gulf and spawns.

Commercial fishing for crabs, Frosch said, include catching crabs in nets, in crab pots, and in trawls. It is most profitable, however, to deal with soft or soft-shelled crabs. Frosch described in detail how a soft-shelled crab begins to shed its shell and the process involved in going from the soft stage to the hard crab stage. During the three years of the crab's life, it is likely to shed between 18 and 20 times, each time increasing his size from an inch to an inch and a half.

Shedding The Shell

The actual process of shedding a shell involves the back part of the crab shell actually separating and the crab backs out of the old shell. Frosch noted that every part of the crab's body, including the covering over his eyes, is completely new. He noted too that if a crab loses a portion of a claw, his new body will have replaced the missing part of the claw.

Frosch also told the Rotarians that during this period, a crab will absorb or take in water to the extent that he will get as much as 70 percent of his body weight in water taken in into the crab's system. As the water is taken in, the crab swells inside of the shell and causes the back portion of the shell to break open and the crab actually crawls out backward. It takes from one-half hour to forty-five minutes for the crab to back out of the shell, at which time the crab continues to take on water to expand to his new size. Frosch says he has seen this process numerous times, but he is still fascinated every time he witnesses the shedding process.

Within twenty-four hours after a crab sheds, its new shell becomes hardened.

Color Change

Fishermen who are familiar with the crab shedding process, know to look for a color change in the crab's shell in order to determine when the shedding process is to take place.

The commercial fishermen who deal in soft-shelled crabs have a variety of ways in which to cultivate soft-shelled crabs. use. He said also in Mandeville there are concrete tanks into which lake water is pumped in order to ultivate the soft-shelled crabs. A third method which Frosch says that he and his father have been experimenting with involves using water from the tap and artificially salting the water and filtering and recycling the water through a 4' x 8' plywood tank.

Frosch brought with him several exhibits showing the different stages of development in the Lake Pontchartrain crabs' growth. Following his remarks, Club President Jim Moore thanked Frosch for addressing the Rotarians, and closed the meeting.





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Frosch Barber Shop