Harbor Branch News



What Oysters Tell Us About Our Lagoon

We’ve been busy shucking oysters at the Harbor Branch Aquatic Animal Health Lab. No, we’re not prepping for a backyard BBQ – we’re studying the health of the Indian River Lagoon (IRL). 

  team shucking

The Aquatic Animal Health Lab team and volunteers shuck oysters.

Why are oysters important?

oysterOysters are a keystone species that provide food and habitat for hundreds of invertebrate and fish species in estuarine systems. Aside from being a keystone species, oysters are also an indicator species as well. Health of oyster populations can be used to monitor the overall health of an ecosystem, and changes in these populations can show evidence of threats to that ecosystem long before other species, such as dolphins and manatees, are affected.

Additionally, oysters are filter feeders and an individual adult oyster can filter up to 50 gallons of water per day! Therefore, healthier and more successful oyster reefs will help clean the polluted waters of the IRL.

Why are we studying individual oysters?

Overharvesting, disease, and poor water quality have proven to be detrimental to the Indian River Lagoon’s oyster population. Various oyster reef restoration efforts have already been put into place and monitored in terms of reef growth and density, but the health of the individual oysters has not been assessed. Monitoring the health of individual oysters provides an understanding of their ability to contribute to further reef growth.

What do we learn from studying oysters?

Through our research methods, we are able to determine the distribution of various pest and parasite species, such as pea crabs and parasitic flatworms, throughout oyster populations in the Indian River Lagoon. We are also able to determine whether oysters in a certain area are eating enough and the percentages of male and female oysters found in that area.

By studying these factors, we can discover in which areas of the IRL oyster reefs are thriving, and in which areas they are in poor health. This information can help government agencies plan oyster reef restoration projects in the most promising regions of the IRL for the greatest chance of success.

What is the process of studying an oyster?

shucking

 Oysters are collected from the IRL and delivered to us at our Aquatic Animal Health Lab (AAHL). The preliminary steps include weighing, measuring, and photographing each individual oyster. The oysters are then shucked open and examined visually for anomalies and pests. Next, different tissues are dissected out for analysis such as preparing histology slides for microscopic evaluation. Other tissue has DNA extracted from them for additional disease evaluation. Further data on internal parasites, sex ratios, and digestive health is recorded and reviewed. 

slides

   The process begins with shucking every  oyster. Oyster samples are prepared for the microscope by being placed in wax, then sliced and stained for slides. 

 Where do the oysters come from?

Oysters are collected from 18 reefs within the IRL. These 18 reefs were spread across the Northern Region (Mosquito Lagoon), Central Region (Sebastian and Vero), and Southern Region (St. Lucie and Loxahatchee). At each site, 30 adult oysters were randomly collected from both a natural and restored reef. 

reef

An Oyster Reef. 

Can the community help?

Yes! Anyone can do their part and assist in the restoration of IRL oyster reefs. There are several volunteer opportunities with the DEP and Florida Oceanographic Society (FOS) to help with restoration projects. For those who are not a fan of directly working out in the lagoon with oysters, that’s okay! There are still ways to help. Speak with your favorite local seafood restaurants and find out if they recycle their used oyster shells. The DEP will be more than happy to take any and all oysters shells to use in their restoration projects. 

volunteer

Florida Oceanographic Society volunteers help with an oyster restoration project. Image Credit: Florida Oceanographic Society 
Who does Harbor Branch work with?
We are working with the Florida Fish and Wildlife Conservation Commission ( FWC ) and the Florida Department of Environmental Protection (DEP) -Indian River Lagoon Aquatic Preserves Unit. Our partners from both of these agencies make the collection of these oysters possible. They collect oysters from all three regions of the IRL for us and deliver them to our AAHL lab. In addition to field work, FWC and DEP are primarily responsible for designing and funding this project. Individuals who deserve recognition beyond the Harbor Branch AAHL include Jeff Beal (FWC), Matthew Anderson (DEP) and Emily Dark (DEP) who presented preliminary findings from research at the Indian River Lagoon symposium this year.  

To learn more about oysters and oyster restoration in the Indian River Lagoon, check out the Florida Oceanographic Society project page ( here ). For more information on the role of oyster reefs in the ecosystem, visit the Florida Department of Environmental Protection here

The quality and condition of oysters directly reflects the IRL's ecosystem health. Oyster health indicates the health of crustaceans, fish, marine mammals, and all other inhabitants of their community. So if you enjoy the Indian River Lagoon for its recreational activities (fishing, swimming, kayaking etc.) thank the oysters! More than just being tasty, they help to maintain good water quality in the IRL.