CULTURED PEARLS

CULTURED PEARLS. Despite the end of the pearl button industry along the MISSISSIPPI RIVER, the demand for clam shells by 1985 had led to fishery managers in three states bordering the river becoming concerned. The managers proposed limiting the open season for clamming to May 1-September 15. They also proposed creating a minimum-size limit of 3.75 inches on WASHBOARD mussels and 2.75 inches on all other varieties.

The concern came as harvesting of clams from 1981-1985 averaged 1,087 tons of mussel shells valued at $500,000 for the Japanese cultured pearl industry. Biologists believed the harvesting exceeded natural reproduction levels. (1)

Thirty years after the last button factory closed, clam shells were found to be an important part in the production of cultured pearls. Natural pearls are created by oysters which have a grain of sand accidentally enter into its shell. To relieve the irritation, the oyster secretes juices which gradually harden. Replicating nature, custom pearls begin when the clam shells are cut into small squares and then polished into small balls. Placed in live oysters off the coast of Japan, the balls in from two to five years are covered in the hardened juices of which pearl are made. (2)

In 2021 there were no examples of this industry being practiced in Dubuque.

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Source:

1. Pauly, Larry, "Fishery Managers From Five States Aim to Put Muzzle on Mussel Harvest," Telegraph Herald, December 17, 1985, p. 7

2. Shaffer, Jim, "Clam Fishing on Mississippi River Supplies Pearl Industry in Japan," Telegraph Herald, August 3, 1964, p. 18