Take PVC pipe. Attach to a home water pump. Add water.
It’s a simple recipe, but one that might be enough to help move millions of the migratory fish species known as Alabama shad over dams, so they can spawn in rivers throughout the southeastern United States. For millions of dollars less than conventional methods. With potentially big gains for sport fisheries in those rivers.
“It’s low cost, low risk and low tech,” says Steve Herrington, director of freshwater conservation for The Nature Conservancy in Florida. “You can buy any of the basic equipment at Home Depot. And we have the science to back it up.”
The Nature Conservancy and partners are leading a research effort to determine if simple, inexpensive techniques can pay big dividends for migratory fish populations. The initial results are promising.
An Amazing Fish Story
Getting fish over dams typically costs huge sums. A fish ladder for even a small dam can run $2 to $4 million. Proposed fish ladders for Pacific salmon on four dams on the Klamath River were estimated to costs $250 million.
But you don’t hear about a dime for Alabama shad. Why? After all, the closely related American shad used to be as American as apple pie, the source of a major American canning industry in the American colonies, as covered in John McPhee’s excellent book, The Founding Fish. (Even George Washington had a cannery).
But today: “Most people don’t even know what a shad is,” says Herrington — even though some biologists think restoring the fish to the upper reaches of southeastern rivers could boost bass fishing there.
“We need to take what we know about the species and find cheap methods to help them migrate,” he says.
The Conservancy is working with partners from the Georgia Department of Natural Resources, Florida Fish and Wildlife Conservation Commission, U.S. Army Corps of Engineers U.S. Fish and Wildlife Service and the National Marine Fisheries Service to assemble a more complete picture of the shad — its life history, its migration patterns, its population status.
I recently joined Herrington, Auburn University research assistant Chase Katechis and Georgia DNR biologist Travis Ingram to catch and tag Alabama shad in the Apalachicola River, one of the largest rivers in the region.
As the team netted shad, I was able to see them up close: A plate-sized silvery fish that looks like it belongs in the ocean — and indeed, for much of its life it lives somewhere in the Gulf of Mexico (even scientists don’t know exactly where). In saltwater, it bulks up on other fish, but little else is known.
Come spring, shad surge up rivers like the Apalachicola. They don’t feed, instead putting their energy into reaching suitable spawning areas, where they lay eggs and (scientists think) die. The young shad migrate back to the ocean, continuing the cycle.
It’s a journey fraught with peril, as the fish I held so dramatically attested: Nearly every shad contained gashes on its side — the work of the longnose gar, a somewhat unsettling predatory fish with a protruding snout full of sharp teeth.
Overhead, ospreys carried other fish off in their talons.
But those perils are nothing compared to the biggest obstacle: a large dam that sat just upstream of our anchored boat.
In a Lock, the Key to Solving the Shad’s Problem
The dam’s exact effect on shad population declines wasn’t well known: little documentation exists for historic shad runs. But one thing was clear: shad weren’t getting past the dam, at least not in numbers that mattered. Fisheries surveys in the 1990’s noted few if any shad above the dam.
“The dam isn’t going away. It provides power for thousands of people,” says Herrington. “Given that, how can we work with it? How can we get fish over it without any money?”
There seemed to be a ready-made solution: A boat lock.
It operates as any lock does. A boat enters the lock at the bottom of the dam, as a door closes behind it. The lock fills with water (six million gallons in this case), raising the boat to the level of the impoundment behind the dam. A door opens and the boat exits above the dam.