Will captive-reared Gulf sturgeon, new to the wild, perform identically to wild Gulf sturgeon? Is there suitable Gulf sturgeon habitat above Jim Woodruff Dam in Chattahoochee, Florida? Are there any unknown Gulf sturgeon populations in the Apalachicola-Chattahoochee-Flint River System of Georgia and Florida?
Eleven captive-reared Gulf sturgeon recently were released above and below the dam on to begin their journey toward the answers.
"We have a lot of questions that we hope this year-long study will answer," said Sam D. Hamilton, Southeast Regional Director of the U.S. Fish and Wildlife Service. "All of these fish have been surgically sterilized and outfitted with radio transmitters so that they can make us aware of suitable Gulf sturgeon habitat for future reintroductions or maybe even unknown wild sturgeon populations."
According to Robert Bakal of the Warm Springs Regional Fish Health Center, Gulf sturgeon were once abundant in the Appalachicola-Chattahoochee-Flint River System, but now this species, federally listed as threatened in 1991, has only one known population of 300 to 400 sturgeon located below the dam. Activities such as dams, dredging, and channel maintenance have helped deplete populations of this species. Nationally, the Gulf sturgeon is found in the Gulf of Mexico and its drainages, primarily in Louisiana, Mississippi, Alabama, Georgia, and Florida.
Service biologists are conducting this pilot study in cooperation with the Georgia Department of Natural Resources and the Florida Fish and Wildlife Conservation Commission in the hopes that if it is successful, similar studies can be conducted in other reservoirs. This type of study has never been attempted with Gulf sturgeon. A similar project is now under way with another federally-listed species, the endangered shortnose sturgeon in the Savannah River.
"We're excited to be involved in this pilot sentinel project for the Gulf sturgeon," said Rob Weller, Senior Fisheries Biologist, Wildlife Resources Division of the Georgia Department of Natural Resources. "We will be using telemetry to monitor their progress and to establish the critical data necessary to aid in this prehistoric fish's recovery to its historic range."
"The U.S. Fish and Wildlife Service has our support in this research project," said Ed Moyer, the Florida Fish and Wildlife Conservation Commission's Director of the Division of Freshwater Fisheries.
Today, scientists released three captive-reared females from the Jim Woodruff Dam at the boat ramp, below the dam. Two of the animals were 7-year-old sub-adults and one was a four-year-old juvenile. Eight animals were also released above the dam; six 7-year-old sub-adult males, one 4-year-old juvenile male, and one 7-year-old sub-adult female. In addition, five Gulf sturgeon from the wild population have been tagged and fitted with radio transmitters, so that the behavior patterns of captive-reared and wild sturgeon can be compared. All of the fish will be tracked throughout the study, and details about the habitat they are utilizing will be recorded.
"We expect that the three females released below the dam will probably join the wild population, " said Bakal. "We're hoping that those released above the dam will locate suitable sturgeon habitat or previously undiscovered sturgeon populations there."
The 7-year-old fish have already been pioneers in that they all were among the first fish nationwide to receive cataract surgery. Two of the surgeries were filmed by the Discovery Channel's Animal Planet for an animal surgery program that aired a month ago.
The captive-reared sturgeon will remain in the Apalachicola-Chattahoochee-Flint River System for about a year. After that, scientists hope to be able to retrieve them to serve as underwater detectives in other reservoirs. By then, we hope to know the answers. Is there suitable habitat for Gulf sturgeon above the Jim Woodruff Dam? Do captive-reared sturgeon in the wild behave like wild-reared sturgeon? Are there other, as yet unknown, populations of the Gulf sturgeon, and can we help these species regain a foothold in the Appalachicola-Chattahoochee-Flint River System?
A subspecies of the Atlantic sturgeon, the Gulf sturgeon has a bladelike snout, and its body color is light brown to dark brown and pale underneath. The sturgeon reaches a maximum length of about eight feet and weighs as much as 500 pounds. The fish is anadromous, participating in freshwater migrations. Sturgeon primarily feed on invertebrates such as worms, mollusks, and insect larvae. The Gulf sturgeon is a long-lived species with an average life span of at least 40 years.
For more information about the re-introduction of the Gulf sturgeon, contact Robert Bakal of the FWS at (706) 655-3382 or Robin Hill with the Georgia Department of Natural Resources at (770) 761-3035.