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TALLAHASSEE - Since 1970, Florida's
calico scallop, Argopecten gibbus (Linne, 1758), has had its ups and downs. Of the estimated 400-plus scallop species, A. gibbus was once one of the three most common varieties found in the market. In 1984 a harvest of 39.3 million pounds was valued at $75 million, a record.
Since then, the industry has been forced to shut down due to a lack of scallops. This unpredictable
fluctuation has created hardship for processing
plants, fishermen and industry workers,
according to the Jacksonville (FL) Shell Club's
Shell-o-Gram.
Biologists have been collecting production and reproductive data on the calico scallop since the
mid-1980s. Florida Sea Grant researchers
Norman Blake and Kendall Carder are using remote
sensing techniques to predict scallop availability
for commercial harvest. Satellite imagery gives water temperature, chlorophyll content and other reproduction-linked information.
Overall, the research indicates a relationship among
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such characteristics as temperature, Gulf Stream position, and the reproductive cycle of
the calico scallop. Landward movement of the
Gulf Stream brings colder nutrient-rich water
which induces spawning and produces more
scallops.
Spawning for the calico scallop typically occurs
twice a year, once between March and June
and a second time usually between July and December. Without a successful autumn spawn the
number of scallops that die during the winter
may leave too small a population to support a
commercial fishery.
In December 1988 scallopers began to find large numbers of dead scallops in their catches. Within a month, mortality was close to 100 percent.
Examination showed that a parasitic Haplosporidian of unknown species had taken over the digestive tract of the scallops and virtually starved them to death.
Blake's research was cut short by high mortality
on the Canaveral scallop beds in January, 1989.
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