What’s happened to the prehistoric river giants of Alabama?

Sponsored

Primitive. Ancient. Rare. These are the words that best describe Alabama’s three species of sturgeon, a fish that dates back 245 million years in fossil records. It’s likely that you’ve never heard of a sturgeon, much less seen one. 

 
In our third installment about efforts to bring back animals to the state of Alabama, we examine one of Alabama’s oldest fish species and how we could possibly bring them back from the brink of extinction.

Freshwater Biodiversity

Before we do a deep dive into sturgeons, you may not know that the state of Alabama has more kinds of fish, mussels and snails in our rivers and streams than any place in North America.

According to The Nature Conservancy and many other groups that examine and rank biodiversity in the United States, Alabama is:

• 1st in the U.S. in the number of freshwater fishes with 332 kinds of fish—27% of all fish species in North America. 
• 1st in the U.S. in the number of freshwater mussels with 180 different types—59% of all mussel species in North America.
• 1st in the U.S. in the number of freshwater snails with 202 kinds of snails—28% of all snail species in North America.

Our Sturgeons

Globally, there are 27 kinds of sturgeons. In Alabama, we have three residents: the Alabama sturgeon, the Gulf sturgeon and the Lake sturgeon. Each one is rare and protected by state and federal agencies.

Recently, we interviewed Steve Rider, Rivers and Streams Fisheries Supervisor for the state about each of the three sturgeons and the efforts to recover them.

Here are their stories.

The Alabama Sturgeon is the Rarest Fish in the World

The last time an Alabama sturgeon was seen and observed by fish biologists was in 2009. No one had seen one for 11 years. As a result, it holds the distinction as one of the rarest fish in the world, along with being the smallest sturgeon (it weighs less than four pounds). Some scientists believe it is functionally extinct, but not Rider. 

“Right now we are collecting water samples that are used to detect the DNA of the Alabama sturgeon in the river. Working with the University of West Florida, we collect samples that can tell us a specific location and time an Alabama sturgeon was detected. It helps us to tell when and where to concentrate our sampling efforts.”

Sounds like something out of an episode of NCIS, doesn’t it?

Scientists have taken environmental DNA (eDNA) samples (a technology that identifies a fish and other creatures via DNA in rivers and streams) throughout the historic range of the Alabama sturgeon.  They are the Tombigbee, Alabama and Cahaba rivers. Despite not seeing the sturgeon for more than a decade, eDNA has persistently detected the presence of the fish.  

Known to have spawned north from the Alabama and Tombigbee rivers to the clean smooth and slippery shoals of the Cahaba River, the fish’s demise occurred due to the loss of free-flowing riverine habitat. This happened thanks to the many dams and locks blocking its migration.

Will we ever see the Alabama sturgeon again? 

“The goal is to collect enough [sturgeon] to get a brood stock going to establish a hatchery,” said Rider. “I’m confident they are there, but the longer and longer you go, it gets tougher to catch them. They are hanging on by a thread right now.”

The Gulf Sturgeon are in a Dwindling Habitat

Gulf sturgeon are anadromous fish. That means they are born in freshwater, live most of their lives in saltwater and must return to freshwater to spawn. This is why it is imperative for the species to swim from the rivers to the ocean and back. For science geeks, we also have catadromous fish who do just the opposite. They are born in saltwater, live their lives in  freshwater and return to the ocean to spawn. The American eel is an example of a catadromous fish found in Alabama.

Gulf sturgeon can be found from Louisiana to Florida. In Alabama, their native range before overexploitation in the 1890s and then the construction of dams and locks in the1900s was the entire Mobile River Basin. That’s from the Mobile Delta to the Coosa River.  

Today, Alabama’s Choctawhatchee River is thought to have the second highest number of Gulf sturgeon next to the Suwannee River in Florida. According to Rider, the Department of Conservation has tagged 149 sturgeon. This provides our state’s scientists valuable insight into sturgeon habitats and spawning races.

Back in the 1940s, Gulf sturgeons were found as far up as the Coosa and Tallapoosa rivers. Alabamians caught them for meat, not caviar. They were the size of an Auburn University offensive tackle, weighing 300-400 pounds.   

Today, these ancient fish that live up to 60 years, tip the scales at a svelte 100-150 pounds. The largest Gulf sturgeon Rider ever collected was last fall, weighing about 165 pounds. 

The lack of free-flowing river habitats and dams blocking the Gulf sturgeon’s movement continues to hurt its chances for recovery. 

“They [Gulf sturgeons] can’t travel through all the dams and locks in the Mobile river system,” added Rider. “We don’t have any confirmed evidence of fish above the locks right below Claiborne Dam. Except for eDNA, which says there may be a fish or two above the dam, it keeps them from making it to the Cahaba, which has great habitat to spawn since the dams prevent it.”

Lake Sturgeon—A Two Decade Effort

Similar in size to the Gulf sturgeon, the Lake sturgeon calls North Alabama home. 

Since 2002 and 2003, the state of Alabama with the help of the U.S. Fish and Wildlife Service, Tennessee and Georgia fisheries staff have been stocking the Tennessee and Coosa rivers with Lake sturgeon. Before the 2000s there were only a handful of Lake sturgeons ever collected in these rivers. Two decades ago, the southern states decided to stock the rivers with Lake sturgeon eggs from Wisconsin. In 2020, anglers regularly report seeing Lake sturgeon as far south as Lake Mitchell.

The jury is still out about whether the stocking efforts will ultimately work.

“We are not sure if they are reproducing yet,” said Rider. “They are not sexually mature until they reach 20 years of age. We are just at the point to see if they are reproducing. The goal is to have a self-reproducing population. There is no evidence that there is any spawning yet.”

Fish Passage Team

Aside from stocking North Alabama rivers with Lake sturgeon and efforts to catch the elusive Alabama sturgeon, another promising initiative is finding a way to reconnect our rivers.

Groups are coming together to develop a plan to help sturgeons and other creatures pass through a number of locks and dams on our rivers in South Alabama. 

The Nature Conservancy in Alabama (TNC) has formed a “Fish Passage Team” made up of state and federal agencies, universities and the Corp of Engineers to accomplish this task.

“When Claiborne and Miller’s Ferry Locks and Dams were put up on the Alabama river, it functionally disconnected the Gulf of Mexico from the Cahaba river,” explained Jason Throneberry, director of freshwater programs for TNC. “With fish passage at those two structures, we can functionally re-connect the Gulf of Mexico to the Cahaba River, specifically for migratory fish like sturgeons in Alabama.”

The team hopes to conduct a feasibility study that will research ways we can reconnect our rivers and get them flowing again.

What Can You Do

What can you do to support efforts to bring back our state’s sturgeons?

1. Support the Alabama Department of Conservation and Natural Resources Freshwater Fisheries Division by purchasing a specialty license plate. 
2. Buy a fishing license. Even if you don’t fish, license fees used to protect and conserve fish like the sturgeons. Also, for every dollar spent on a license plate, the federal government matches it with $3. 
3. Support the Nature Conservancy in Alabama’s “Fish Passage Team.”
4. Support the organizations that keep the rivers clean, Waterkeepers Alabama (includes the Cahaba Riverkeeper, Tennessee Riverkeeper, Black Warrior Riverkeeper, Mobile Baykeeper, Choctawhatchee Riverkeeper and Coosa Riverkeeper, Little River Waterkeeper), the Cahaba River Society and Alabama Rivers Alliance.

And if you catch a sturgeon on the river, snap a photo on your phone and send it to steve.rider@dcnr.alabama.gov. Then, of course, be sure to release it.

Did you miss our first two installments in this series? Check out our stories about black bears and red-cockaded woodpeckers making a comeback.

Sponsored by: