Nelson Beltran

UC Santa Barbara

Behavioral Responses of Cultured White Abalone (Haliotis sorenseni) to Predatory Sea Stars in a Laboratory Experiment


The White Abalone (Haliotis sorenseni) isa critically endangered speciesthat will likely go extinct without human intervention. Efforts toenhance wild populations are underway by the White Abalone Restoration Program throughspawning, raising, and eventually reintroducingjuvenile white abalone into the wild.However, the high risk of predation on these captive-bred abalone, which are naïve to predators, threatens our restoration efforts.This summer, I studied the behavioral responses of captive-bred white abaloneto a natural predator, the Giant Spined Star (Pisaster giganteus), in a laboratory experiment. Specifically, I asked:a) docaptive-bred abalone display defensive behaviors in response to the predatory sea star?,and b) canthey learn to escape more quicklyafter multiple encounters with the predator? To answer these questions, I observed the behavioral responses of individual captive-bred juvenile white abalone to tactile stimulus from either a sea star (experimental treatment) or an abiotic sponge (control treatment) over five-minute trial periods. I first touched the abalone with the sponge and 3 days later, I placed the sea star on the abalone. Finally, I exposed the abalone to the sea star two more times, with one day in between each exposure. Wefound that abalone have innate reflexes to predators which differ in increased variability and extremity of response from a non-predator stimulus. We also found that abalone can learn to escape more quicklyfrom sea stars afterjust one encounter.With these findings, we can inform methods to introduce captive-bred white abalone into the wild, so that there may be a better chance for them to escape sea stars after release.

UC Santa Barbara Center for Science and Engineering Partnerships UCSB California NanoSystems Institute