Biologists concerned dredging Savannah River could affect prehistoric fish

A state study of shortnose sturgeon in the Savannah River could lead to more protection for the endangered fish as officials prepare plans to deepen the river.

The Georgia Ports Authority says the Savannah harbor needs to be deepened from 42 to 48 feet to accommodate a new generation of larger tanker and container ships. The ports authority is in the midst of a lengthy approval process for the dredging, which could begin next year and be completed by 2014.

State biologists are unsure of how a deepened channel would affect the sturgeon, saying more study is needed to understand how the fish use the river.

"If they use these areas as critical habitat for nursery grounds or spawning, then deepening will alter that habitat," said Bill Post, an official with the South Carolina Department of Natural Resources. "They may be able to find new habitat, but they may not."

For the past two years, the state agency has tagged the fish using a $225,000 grant through the National Marine Fisheries Service. The study will continue until September, so numbers haven't been tallied.

About six times a month, biologists catch the sturgeon. If they continually catch fish they've already tagged, Post said, the study would show the population is not robust. If they catch more fish without tags, Post said, it would show the stock might be improving.

In addition to the study, DNR is working with the Nature Conservancy to track the fish with technical equipment. Transmitters are being surgically implanted into some of the fish.

When the fish swim by an underwater receiver -- usually anchored to a tree or the river bank -- the equipment records the fish's location in the river and the time of year.

"We have found that they're moving upriver to spawn," said DNR marine biologist Claudia Jendron. "That could potentially be spawning grounds and that would be great because then we could protect the area."

Post said the fish generally spawn in February or March. They are semi-anadromous fish, meaning they live in saltwater and spawn in freshwater. If the fish are coming to the Savannah River to spawn, the exact locations should be pinpointed by the Nature Conservancy equipment, Post said.

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