Aquaculture America 2021

August 11 - 14, 2021

San Antonio, Texas

BEHAVIORAL CONDITIONING THROUGH HABITUATION TO INCREASE POST-RELEASE SURVIVAL OF HATCHERY-REARED RED DRUM Sciaenops ocellatus

 
Tyler Schacht*, Kim Withers, Robert Vega, & John Scarpa
 
Perry R. Bass Marine Fisheries Research Station
Texas Parks and Wildlife Department
Coastal Fisheries Division
Palacios, TX 77465
Tyler.Schacht@tpwd.texas.gov

Three sets of experiments were conducted from July to December 2016 to investigate whether habituation and habitat complexity in rearing ponds (0.2 ha) affected post-stocking predation of hatchery-reared red drum, Sciaenops ocellatus. Three structurally different habitat treatments: 1) non-vegetated (normal rearing environment), 2) artificial seagrass, and 3) artificial seagrass with predator exclusion cages were used to assess if habitat complexity influenced growth and condition. Survival from predation was assessed by exposing red drum to free-roaming predators (pinfish, Lagodon rhomboides) in experimental 'wild' ponds (0.2 ha) for 24 hours. Fish growth (TL) was found to be affected by trial (i.e., temporal) but not by any treatment (P < 0.0001 and P = 0.178, respectively). Prior to the introduction to red drum into experimental 'wild' ponds with predator exposure, condition factor (K) of fish was found to be affected by trial and treatment with an interaction (P < 6.95e-16, P = 0.0013, P = 0.006, respectively). Condition factor was significantly lower in the artificial seagrass treatment with predator exclusion cages (K = 0.82), as compared to the non-vegetated and artificial seagrass treatments (K = 1.06 and K = 1.09, respectively), prior to predator exposure. Although condition factor may have been affected by the addition of predator exclusion cages, data suggests that survival during culture increased with habitat complexity. In conclusion, habitat complexity improved behavioral mechanisms (i.e., foraging, predator-avoidance), thus increasing post-release survival of hatchery-reared red drum.