Keeping Their Eyes on Bay Scallops

Researchers monitor the health of Florida's bay scallop populations.

A bay scallop survey is conducted underwater

The bay scallop is a popular addition to the dinner table for seafood lovers, but many sit down to eat without thinking about what it takes to ensure that they remain plentiful for years to come. Fish and Wildlife Research Institute (FWRI) biologists have monitored bay scallop populations along Florida's Gulf coast for the better part of two decades and are involved in local restoration activities. 

In 1991, bay scallops were still harvested by both recreational and commercial fishers. To address overharvesting concerns, FWRI scientists initiated bay scallop research designed to assess local populations. Researchers found the concerns were justified, as bay scallop numbers in some areas were short of the levels believed necessary to support viable populations. In 1994, new regulations eliminated commercial harvest of bay scallops and closed some areas to all harvest. 

Although bay scallop populations remain relatively stable in some traditional harvest areas, other areas that were once harvested have unstable populations that do not seem to be recovering. Researchers monitor bay scallop abundances annually along Florida's Gulf coast from Pine Island Sound to St. Andrew Bay. They survey study sites each June before the recreational season opens. At nine of the 10 study sites, researchers survey 20 stations – 10 at the other site – located in seagrass beds in depths up to 10 feet. At each of those stations, researchers deploy a 300-meter (984.3 feet) weighted transect line and two divers – one on either side of the line – each count all scallops within a meter-wide (3.3 feet) area along the line, for a total survey area of 600 square meters (1,968.5 square feet). In 2011, researchers conducted post-season surveys to determine population levels after recreational harvest. 

Each month, researchers also deploy collectors made from a plastic panel and citrus bag at the survey sites. They use the collectors year-round to monitor larval and juvenile scallops called spat that settle into local seagrass beds. Researchers process more than 100 collectors each month and count all scallop spat present on each collector. FWRI staff compiles the recruitment (spat) and abundance data and compares the “health” of local populations to that of previous years. Based on those comparisons, researchers can better guide restoration efforts and inform managers of the stability of Florida’s scallop populations. 

FWC Facts:
A shrimp escapes predators by quickly pulling its abdomen in toward its carapace (body). This motion shoots it through the water backward.

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