Water Quality Monitoring Supports Shellfish Aquaculture in Florida

Clam work boats at a commercial lease area off Cedar Key, Florida are harvesting their crops. (Credit: University of Florida / IFAS)

Shellfish aquaculture in Florida has seen a lot of growth since the industry’s start in the 1990s, generating $42 million in sales revenue in 2023, according to the 2023 USDA Census of Aquaculture.

In 2000, the USDA Risk Management Agency (RMA) launched a pilot crop insurance program for cultured hard clams in Florida. This program provided significant financial support.

Under the federal crop insurance program, farms were compensated for losses resulting from disease, hurricanes, hypoxia, and other stressors that could lead to clam mortalities. In order to file for these reimbursements, water quality data was needed to accompany claims—and so began water quality monitoring in the state.

Leslie Sturmer, an extension agent for the University of Florida, Shellfish Aquaculture Extension Program, has been involved in the monitoring program since its inception. Sturmer was part of the founding group that introduced shellfish aquaculture to the west coast of Florida and kick-started the monitoring program in Cedar Key.

University of Florida staff cleaning a multi-parameter sonde (In-Situ AquaTroll 600) at a monitoring station located within an aquaculture use zone off Cedar Key, Florida. The sonde measures water temperature, salinity, dissolved oxygen, and chlorophyll every half hour, 24 hours a day, seven days a week. (Credit: University of Florida / IFAS)

Monitoring Shellfish Aquaculture Operations in Cedar Key, Florida

Today, Sturmer works directly with growers so they can make informed decisions about the operation of their farms. She manages and maintains the continuous monitoring stations located along the coast, and shares data with researchers who are interested in water quality conditions in Cedar Key.

While a lot of Sturmer’s work now focuses on upkeep and the continuation of the project, she is also tasked with helping farmers find resources when needed.

She explains, “We were severely impacted by three hurricanes over a 13-month period. So, a lot of my focus over the past year and a half has been helping to find the resources to assist the industry in their recovery.”

More recently, Sturmer has started to play an important role in getting the new off-bottom oyster aquaculture industry off the ground by helping farmers apply best practices, source seed, and manage operations.

Still, water quality monitoring has remained a key part of the project and Sturmer’s work, with a large part of her day-to-day responsibilities revolving around maintaining the program’s two monitoring sites.

When the program first started, there were nine monitoring stations collecting data. However, once the federal project ended, the funds to keep all these stations running also ended. So, the team assessed which stations were most needed—deciding upon the Dog Island and Gulf Jackson stations—and the USDA Risk Management Agency continued to fund these select sites.

These specific sites were chosen due to the impact they had on Cedar Key’s hard clam industry, which provides close to 95% of the state’s crop. Because clam aquaculture was so important to not only this region’s economy, but also the entire state’s, these sites were maintained.

More recently, Florida State University (FSU) has installed two water quality monitoring stations at lease areas in the Panhandle – Alligator Harbor and Oyster Bay.

Aquatic growers pulling an oyster culture bag for inspection. In the background are floating bags attached to longlines on an open-water farm in the Gulf of America. (Credit: BowStern Communications)

The Dog Island and Gulf Jackson systems include an In-Situ Aqua TROLL 600 multiparameter water quality sonde and a telemetric data logger that posts data to a public portal every 2 hours. Water temperature, salinity, dissolved oxygen, and chlorophyll measurements are recorded 24 hours a day, seven days a week using these systems.

These sites are cleaned about every 7 to 10 days in the summer, and data is downloaded every 2 hours to the dashboard. During site visits, the team collects grab samples and discrete measurements using standard spectrophotometric methods to calibrate the chlorophyll sensor.

The Alligator Harbor and Oyster Bay stations collect water quality data using YSI EXO sondes.

Farms for Aquaculture Research & Monitoring of Shellfish (FARMS)

In 2023, the program colloquially known as Oyster FARMS was started as a means of increasing monitoring efforts in the region. The program was initiated in response to mortality events and is now a network of eight shellfish farms in Alligator Harbor, Apalachicola Bay, Indian River, Indian Lagoon, Mosquito Lagoon, Cedar Key, Skipper Bay, and Pensacola Bay.

Each of the participating farms were given an Aqua TROLL 100 conductivity logger to collect conductivity (calculates salinity) measurements continuously.

Farmers can connect to the loggers with Bluetooth and retrieve the data whenever they’re near the loggers or before planting new seeds to ensure that the salinity of the farm waters matches that of the hatchery.

The data is also sent to Sturmer, who compiles data from all of the farms on an online data portal. “Then we create graphs so that we can kind of start seeing the differences in these water bodies, and how it relates to oyster growth and survival,” explains Sturmer.

In-Situ AquaTroll 100 dataloggers are placed inside oyster culture bags at seven commercial farms across the state to continuously monitor water temperatures and salinities. (Credit: University of Florida / IFAS)

Data Use and Moving Forward with Informed Aquaculture Practices

All of the collected data is compiled into a continuously growing dataset that records conditions in Florida’s shellfish aquaculture farms. As the dataset in Cedar Key approaches its 20-year milestone, Sturmer looks toward the future, thinking of ways to expand the capabilities of this project.

Being able to look back through the data allows Sturmer to identify trends that contribute to high or low production, improve operations when possible, and understand the impact of various environmental stressors on aquaculture.

Stressors like high temperatures, fluctuations in salinity, and harmful algal blooms can impact production and have a negative impact on shellfish health and growth rates. Sturmer gives an example of how salinity, in particular, can have a significant impact on seed survival.

Because most of the seed for the farms comes from elsewhere in the state, differences in salinity from hatchery waters to the aquaculture locations can lead to losses if they are planted when salinity is higher or lower than the waters they were reared in.

Using the 20-year dataset, Sturmer can pinpoint what leads to salinity or temperature spikes, which helps ensure farmers are planting at opportune times, as well as recording how the environment has changed over the past two decades, like climate change-induced temperature spikes.

The monitoring stations collect the data needed for practical management of these facilities, protecting a multi-million-dollar industry that provides food nationally and is essential for the local economy.

Florida’s shellfish aquaculture operations are dependent upon current environmental conditions, and variations can lead to losses if not properly managed. The Oyster FARMS program and the two real-time stations managed by Sturmer provide essential data to shellfish growers, protecting this key industry.