Integrating Data From Aerial Surveys, Telemetry, and Biological Sampling to Assess Red Drum Spawning Populations

Advances in our understanding of effective breeding populations, spatial dynamics, and the role of spawning population age structure are changing how we assess productivity in marine fishes.  Red drum spawning populations off Southwest Florida have been sampled in 1996-1998, 2006-2009, and in an on-going study started in 2012.  In the ten year period between initial studies, age distributions became more extended, with increasing numbers of fish older than 14.  Spawning aggregations are more consistently identified in nearshore Tampa Bay waters than nearshore waters off the nearest estuarine neighbor, Charlotte Harbor.  However, juvenile indices show similar temporal patterns.  In 2012, three red drum spawning aggregations were sampled by purse seine and 1800 fish assessed for size, reproductive state, and genetics.  An additional 60 fish were implanted with acoustic tags to evaluate connectivity between the Tampa Bay and Charlotte Harbor nearshore spawning sites.  Weekly aerial surveys of nearshore waters from north of Tampa Bay to south of Charlotte Harbor, resulted in the identification of eleven red drum aggregations from late September through October, all off of Tampa Bay.  Thirty-four of the acoustically-tagged fish were detected after the date of implantation, thirteen of which moved to Charlotte Harbor from Tampa Bay nearshore habitat.