The U.S. Fish & Wildlife Service and the National Marine Fisheries Service are proposing critical habitat for the threatened Gulf sturgeon. As part of this process, public input is being sought so that an informed decision can be made regarding critical habitat designation.

Gulf Sturgeon - Historic & Current Information

Gulf sturgeon are found in large river systems from Louisiana to Florida. However, very little is known about the distribution of these fish outside of the large watersheds. In addition, the fish may occupy only discrete areas in the watersheds (all less than 100 miles long) during the summer and are difficult to research. Furthermore, the upper reaches of the river systems and numerous tributaries are not thoroughly investigated for Gulf sturgeon due to limited personnel and time constraints. The Panama City Field Office initiated a study seeking historic and current Gulf sturgeon information in largely uninvestigated areas. Over 100 signs requesting Gulf sturgeon information were placed at boat ramps and high-use areas in Florida, Alabama, Mississippi and Louisiana. Service personnel from Daphne, Ala., and others from Louisiana Department of Wildlife, Fisheries and Parks, University of Southern Mississippi, Mississippi State University and Troy State University assisted with placing the signs.

Although response to the Gulf sturgeon information request has been limited, several reports are noteworthy. Recent Gulf sturgeon sightings in the Mobile Delta, the Intercoastal Waterway near Orange Beach, Ala., and a number of reports from anglers fishing off Panama City Beach piers, indicate that Gulf sturgeon are swimming along the Gulf coast.

Gulf Sturgeon Trawl Avoidance Study

The Panama City Field Office assisted researchers from the University of Southern Mississippi (USM), Louisiana Department of Fish, Wildlife and Parks, National Marine Fisheries Service (NMFS) and other U.S. Fish and Wildlife Service offices in Alabama and Louisiana in a study to determine if Gulf sturgeon were susceptible to being caught during winter shrimp trawling operations. The Caretta, a 40-foot NMFS trawler, made several passes through areas in the Mississippi Sound offshore of Pascagoula, Miss., where adult Gulf sturgeon equipped with sonic tags were located. A camera attached in the throat of the trawl recorded the forward progress of the trawl as it passed through designated Gulf sturgeon locations. No Gulf sturgeon were captured in the trawl or were recorded in the trawl camera. Furthermore, triangulation telemetry monitoring of a Gulf sturgeon indicated that the fish moved away from the trawler on several successive trawling attempts to capture the fish.

Gulf Sturgeon Diet Studies

The majority of Gulf sturgeon feeding and growth periods occurs in the marine environment during the winter. Panama City Field Office biologists, working with University of Florida researchers, collected five Gulf sturgeon in the Alaqua Bayou and Choctawhatchee Bay in April 2003. The sturgeon were captured using stationary sinking gill nets and ranged in weight from 10 to 135 pounds. Food items were extracted from the fish using a non lethal lavage procedure. Biologists also conducted a follow-up study in the eastern portion of Choctawhatchee Bay in May 2003, where 32 fish, weighing from 1.5 to 57 pounds, were collected. Eleven of 14 fish subjected to the lavage procedure yielded food items.

Preliminary analysis of the food items indicated that Gulf sturgeon collected in both areas were feeding primarily on amphipods and lancelets. All fish were released without any ill effects following the procedure.

Juvenile Gulf Sturgeon
Movement & Habitat Use

Gulf sturgeon spend winter in marine estuaries, bays and the Gulf of Mexico. It is during this period that most of the species’ feeding and growth occurs. Documenting the marine habitat use of Gulf sturgeon is a priority task identified in the Gulf Sturgeon Recovery/Management Plan, and very little information is available regarding the over-wintering behavior of juvenile Gulf sturgeon. Five juvenile Gulf sturgeon, weighing from 2 to 4 pounds, were collected near the mouth of the Choctawhatchee River in December 2002. The fish were equipped with sonic tags and monitored for six months. All five fish relocated at least once. Three of the fish over-wintered in the eastern part of the bay within 2.5 miles of the river mouth. Two fish were located 10 to 15 miles away from the capture location, but still within Choctawhatchee Bay. All fish were located in near-shore habitat consisting of sand or mud in less than nine feet of water. Salinity ranged from zero at the river mouth to 1.5 ppt. at the location of the fish farthest from the capture site. In May 2003, one fish was located about 30 miles upstream from the bay and original tagging area in the Choctawhatchee River, known as a Gulf sturgeon summer resting area.

Gulf Sturgeon Marine Movement & Habitat Use

Priority action items identified in the Gulf Sturgeon Recovery/Management Plan include identification of estuarine and marine habitat used by Gulf sturgeon. Three Gulf sturgeon (two in the Apalachicola River and one in the Yellow River) were equipped with pop-up archival tags in October 2002 in an effort to document Gulf sturgeon movement and habitat use during the over-wintering period in marine waters. The pop-up tags were attached to the base of the dorsal fin with 100-pound monofilament line. The tags, which record water temperature, depth and light penetration (to calculate geo-location), were set to release from the fish during the first week in February 2003. Upon release, tag data is transmitted to a satellite. In addition, each fish was equipped with an external sonic tag to monitor movement of the fish once the pop-up tag was released.

Two pop-up tags in the Apalachicola River fish transmitted location data while the remaining tag in the Yellow River did not respond. One pop-up tag surfaced in the Gulf of Mexico about one mile off shore of Tyndall Air Force Base, a known area for Gulf sturgeon over-wintering. This fish was located by its sonic tag signature and was monitored prior to and after its pop-up tag was released. The other pop-up tag surfaced in the Gulf of Mexico about four miles offshore, near the mouth of the Ochlockonee River. The presence of the fish associated with this tag could not be verified by sonic signature detection. Two other Gulf sturgeon, one from the Choctawhatchee River and one from the Apalachicola River, were located in the Gulf of Mexico off Tyndall Air Force Base. These fish were between 1/2 to 1 mile from shore in water depths ranging from 12 to 20 feet. The fish from the Choctawhatchee River was located in the same area used during the previous winter.

An additional study to provide information regarding Gulf sturgeon marine movement was initiated in November 2002. Sonic receivers and data loggers were placed on piers in Panama City Beach, Fla., and Gulf Shores, Ala., in an effort to record coastal movement of sonic-tagged Gulf sturgeon. The study was terminated within three weeks after heavy seas knocked the hydrophones off pier supports at both sites. No data was obtained from either site.

Gulf Sturgeon Recovery Coordination

Monitoring gulf sturgeon is a priority for the Panama City Field Office. Biologists and volunteers use ultrasonic tags to follow gulf sturgeon in five Florida Panhandle river systems. Seventy-six gulf sturgeon were collected, tagged and released in 2003. Ongoing research includes locating the tagged fish and recording vital habitat information. The Panama City Field Office also attached archival tags to three gulf sturgeon. These tags record water temperature, depth and light penetration, and are programmed to release from the fish in winter and transmit the collected data to a satellite.