New Insights into marine migration and winter habitat of gulf sturgeon

Abstract

Migrations and movements of Gulf sturgeon Acipenser oxyrinchus desotoi\rwere determined using satellite pop-up archival transmitting (PAT) tags and acoustic telemetry.\rAdult Gulf sturgeon from four rivers in northwestern Florida were caught with gill nets\rand were tagged with PAT and acoustic tags in the fall of 2001 and 2002. PAT tags were\rprogrammed to release in early February 2002 and 2003 to provide information about\rlocation of late-winter marine habitats. However, only 5 of 25 provided meaningful location\rinformation. Three of the PAT-tagged fish were relocated acoustically near the PAT tag\rpop-up locations, one of which was in Choctawhatchee Bay. Acoustic searches near Gulf of\rMexico pop-up locations led to acoustic relocation of one nonreporting PAT-tagged fish\rand five fish tagged with acoustic transmitters only. Many of these fish were relocated on\rseveral dates in late winter, and many (including fish from the Yellow, Choctawhatchee, and\rApalachicola rivers) were concentrated in a 25-km stretch of the Florida Panhandle coast,\rwithin 2 km from shore, and in depths less than 6 m. A fish that had been tagged with a PAT\rtag in the Yellow River was acoustically relocated in the concentration area and then in the\rChoctawhatchee River the following summer. It returned to the concentration area again\rthe next winter and returned to the Choctawhatchee for the second summer. An acoustictagged\rfish was relocated very near a PAT tag pop-up location about 30 km south of the\rSuwannee River, within 12 km from shore, and in depths of 3–4 m. Pop-up locations and\racoustic relocations showed that the Gulf sturgeon had migrated distances of at least 30–\r180 km. These findings indicate a pattern in which Gulf sturgeon migrate considerable\rdistances along the coastline, sometimes to specific areas of concentration, sometimes\rmixing with other populations, and primarily utilizing shallow (2–6 m), nearshore areas as\rlate-winter habitats. This pattern is similar to that reported by others in this volume for\rAtlantic sturgeon Acipenser oxyrinchus and for green sturgeon A. medirostris.