Gulf Sturgeon Standardized Abundance and Mortality Study: A Two Year Look

Following recommendations from the 2009 Gulf Sturgeon 5-Year Status Review to facilitate and improve the reliability and consistency of abundance and natural mortality data estimates, a standardized data collection process was implemented. Standardized datasheets were developed for use by Gulf sturgeon researchers, along with a corresponding database application for centralized data storage. To assess abundance and natural mortality, a collaborative multi-agency project encompassing several states was implemented in 2010. The aim was to tag a total of 100 mature (>135 cm TL) Gulf sturgeon with internal transmitters in five major spawning rivers each year for three consecutive years. “Gates” were formed using hydrophones and were deployed at the mouths of seven rivers to monitor returns. Hydrophones will be maintained in their gate locations for five consecutive years to determine baseline inter-river migration and natural mortality rates. Preliminary results, including river-specific length-frequencies, catch per unit effort, and recapture rates, are presented from the first two years of data collection. Further work includes the development of a tablet application for real time data entry, the estimation of river-specific age and growth, and determination of river fidelity through tag returns.