Determining the Feasibility of Tagging Age-0 Scaphirhynchus Sturgeon to Evaluate Habitat Use Through Telemetry Efforts

Scaphirhynchus sturgeon populations are species of concern throughout their range.  To revitalize the populations, a thorough understanding of their habitat use during all of their life stages is critical.  However, limited information exists on fine-scale habitat use during sturgeon early life.  To determine whether radio telemetry can be used to quantify habitat use in the field, we assessed growth and survival of age-0 sturgeon tagged with 0.2 gram non-functioning telemetry tags during an 8-week period. Three treatments were evaluated: 1) control, 2) internally implanted tags, and 3) externally attached tags.  Growth and survival varied across treatment groups (all comparisons P<0.05).  Sturgeon with internally implanted tags displayed slow growth and low survival, while sturgeon within the control group and those with external tags showed faster growth and high survival (~100%).  Based on these results, we conducted a field-based telemetry evaluation to determine fine-scale habitat use.  We externally tagged 5 wild age-0 Scaphirhynchus sturgeon with functioning radio transmitters in the Middle Mississippi River (MMR). After a short duration (i.e., less than 24-h) the tagged fish moved beyond the capabilities of the radio telemetry receiver likely due to environmental conditions (e.g., extreme depths and high conductivity) in the MMR.  Thus, we suggest efforts be directed to creating a telemetry transmitter that uses ultrasonic technology (ultrasonic telemetry is commonly used for tracking adult sturgeon in the MMR) while maintaining tag weight and battery life.  Fine scale habitat use of age-0 sturgeon may ultimately be able to be quantified in the future if technologies improve.