Oyster farming has always fascinated me. I remember as a boy going fishing out of Dauphin Island and seeing small skiffs with men with long tongs pulling up wild-grown oysters from the oyster beds and piling them up on the decks of their boats. It looked like hard work, which it was. They would take their harvest to Coden or Bayou La Batre for processing, whether sold by the bag or shucked in pints, quarts, or gallon containers.

These days, the wild-caught oysters are fewer and fewer as oyster beds have been depleted, and conditions for replenishing have become more difficult. Yet, the areas surrounding Scenic 98 Coastal have seen the rise of local oyster farms that produce my favorite flavor, Gulf oyster.

A successful oyster farm operation entails a lot of science and engineering. Water conditions play a huge role, but many methods are used to complete the cycle of growth from seedlings to mature oysters that are ready for harvest. Linda and I, along with our four-year-old granddaughter visited with Dr. Andy DePaola to talk about oysters and where we are in growing these delicacies locally.

Let’s start with the man himself. Andy grew up pier fishing with his dad, Depe, on the North Carolina coast  He earned his BS and MS degrees in food science, microbiology, and marine biology at North Carolina State University and his Ph.D. at the University of Florida.  

He spent his entire 37-year career in public service working as a research microbiologist for the Food and Drug Administration at Dauphin Island Gulf Coast Seafood Laboratory. He worked extensively with microbial oyster safety and was the Agency’s subject matter expert on Vibrio bacteria, He was also Lead Seafood Microbiologist, and National Vibrio Policy Coordinator from 2013 until he retired in 2015.

Upon retirement, Andy honored his father by naming his oyster farm after him, Depe Oysters. For years he tinkered with the best way to grow farm-raised oysters and he officially named the business in 2017. He invented and patented the Shellevator™, a breakthrough invention that pneumatically automates shellfish transport from the seafloor to above-the-sea surfaces and provides seamless portability to escape hazards to shellfish or human health. 

He is also a food safety consultant advising the industry, prominent universities, and international organizations and he serves on the executive board of Shellfish Growers Climate Coalition. To say he knows his stuff is an understatement. 

We visited his home on Mon Louis Island, just south of the mouth of Fowl River on the western shore of Mobile Bay. It’s a beautiful setting where Andy is constantly in motion, experimenting with pier designs, growing a living shoreline, testing and modifying his Shellevators, and living off the land as much as possible with his gracious wife, Dianne.

Andy’s authoritative work with Vibrio, a naturally occurring bacteria common in estuaries, including fish and shellfish, underpins national and international control plans to reduce the risk of gastroenteritis and more severe illnesses from eating raw seafood, especially oysters.

We discussed the current conditions of the natural oyster breeding grounds and the challenges, like increased rainfall upriver that reduces salinity below levels that oysters can tolerate, and ways to restore oyster beds for healthy and harvestable wild-caught oysters. 

“These mass mortality events have occurred more frequently in recent years and often occur when tropical storms stall over the Mobile Bay watershed. A 90-degree heat anomaly in March 2020 woke oysters early from their winter hibernation before the rainy season ended and wiped out an entire crop in less than a week.  It seems like Mother Nature is inventing new ways to kill oysters,” said Andy

In addition, oyster populations have dropped below the critical mass needed for successful breeding. Oysters spawn by naturally broadcasting gametes, (sperm and eggs) into the water where fertilization occurs. In late May when the water temperature approaches 80 degrees, oyster gonads become ripe. When an oyster releases gametes, that triggers gamete release in nearby oysters, as they ingest these while they are filter feeding.

To succeed, there must be a critical mass of oysters to ensure a high fertilization rate. Fertilized eggs become free-swimming larvae and dissipate into the currents. After about three weeks, these larvae mature and settle to attach to a substrate like rock or piling to spend the rest of its life; if they settle in mud, they are doomed. They are attracted to the scent that other oysters release in the fifty gallons of seawater they filter each day.

Andy discusses the changes he’s seen in Mobile Bay since he moved here in 1980. He says the water has become much more turbid, starving submerged aquatic vegetation of the light needed for photosynthesis. The runoff is ladened with pathogens and nutrients resulting in frequent closure for harvesting oysters and harmful algae blooms.

Mobile Bay has historically been subject to hypoxia which are low oxygen events (AKA Jubilees). These were rare on the west side of the bay but have become more common in recent years. These usually occur in July and August after a night of calm water from offshore winds on overcast mornings. Stingrays swimming on the surface and crabs dying in traps are early signs of the Jubilee. A ship’s wake can end a jubilee when it crashes a wave into the shore. 

Ship wakes are increasing and contributing to turbidity and shoreline erosion. This is exacerbated by the protection of shores with seawalls. Bay waters over three feet deep have become so hypoxic that populations of keystone commercial species like Brown Shrimp, Blue Crabs, and oysters have diminished and no longer support commercial harvest.

According to the Dauphin Island Sea Lab, Andy says, “We’ve had about a foot increase of tidal surge since I’ve lived here and it’s rising about one inch every two years. People who used to fire up Coleman lanterns nightly to search for soft shell crabs and gig flounder have largely abandoned the Bay and I rarely see human activity except for cargo ships and barges in the ship channel.”

Andy goes on to say, “Bull Sharks seem to be the big winners. Unlike other predatory fish in the Bay, such as trout that rely on sight, Bull Sharks depend more on sound and smell to find prey like mullet, and they have little competition. Dianne and I caught 160 juvenile Bull Sharks just off our pier in three days and won $7500 for first place in the Guy Harvey Foundation Catch and Release Shark competition during the 2016 Alabama Deep Sea Fishing Rodeo.”

We soon headed to Depe Oysters in Coden to see his farming operation. Andy told us they have over 200,000 oysters growing at a time. We were joined by his partners in the business, Daryl and Christina Steiner, and their son, Crawford, who was in the water tending to the oysters growing on the Shellevators. Many of these oysters are destined to be served raw on the half shell or chargrilled from Steiner’s food truck, The Roaming Oyster.

Andy showed us the bottle nursery on their pier, filled with oyster spat purchased from Auburn University. Water pumped from Portersville Bay flowed through the inverted bottles and fluidized the hundreds of thousands of spat, helping them to grow into young oysters that will eventually be placed into small mesh bags and loaded into Shellevators.

The process involves screening the baby oysters to ensure they are large enough not to escape through the mesh bags. Every two weeks or so, the oysters are rescreened and placed into larger mesh bags until they become mature enough for the largest mesh bags when the growth process is complete. It was fascinating!

Several Shellevators are lined up around the end of the pier, stacked with four levels of oyster bags. Each Shellevator is equipped with multiple air lines, connecting independent lift tanks and a manifold with valves attached to a compressed air supply. Airflow is controlled by sequentially opening and closing valves that float and sink the apparatus for shellfish cultivation.

Shellevators are seamlessly mobile and can be placed at different water depths and exposed to air at low tides or waves that tumble oysters to produce deep cups and polished shells.  The oysters also have to be raised out of the water each week to dry off for a day to keep other marine life like barnacles from colonizing the oyster shells or gear which reduces water flow, growth, and potential value at market.

Oyster Drills (snails) are a common predator that feeds on oysters and is a major pest that frequently has to be picked off by hand to save the crop. As we were leaving, a team from the University of South Alabama’s Dauphin Island Sea Lab arrived to do some research and testing for Oyster Drills.

Depe Oysters is quite an operation. Andy is still tinkering with new and improved versions of the Shellevator. He has begun leasing them to other oyster farm operations through a third-party contract. He patented the Shellevator in 2017.

Now, his focus is expanding Depe Oysters and bringing his product to market. “We are ready,” he says. It’s fun to spend time with someone so knowledgeable and interesting. His passion is real, and he just loves working on new and improved ways of doing things. I believe it’s what drives him.

On a side note, in doing a little research, I learned that Andy had once broken his neck in a body surfing accident while visiting his dad at Topsail Beach, North Carolina. A big wave thrust him into a sandbar. He was able to crawl to shore, and the doctors were able to successfully repair the injury, but he is lucky.

Several of my friends have said they want to see Andy’s operation, and he did invite me to come back. I look forward to staying in touch with Andy and Dianne and appreciate their hospitality. Penny, our granddaughter, was taking it all in, and we feel fortunate to have the caliber of people like Andy who work to educate and help improve the quality of our waters and marine life in the Scenic 98 Coastal area.

Unfortunately, the area was closed from heavy rains the previous week and we were not able to sample the oysters. I can’t wait to taste a Depe Oyster grown from a Shellevator in the perfectly conditioned waters of Porterville Bay in Coden, Alabama, my oyster capital of the world!