Foot injury survival in red abalone (Haliotis rufescens)

Recovery of the U. S. Federal Endangered Species Act-listed white abalone (Haliotis sorenseni) in California, USA depends on the success of a captive breeding program, which requires collection of wild broodstock to maintain genetic diversity. Foot damage is frequently sustained during collection and handling, and severe injuries can be fatal. This study used the proxy species red abalone (Haliotis rufescens) to investigate the ability of abalone to survive foot injury by administering foot injuries varying in severity and monitoring subsequent health and survival. In a preliminary study, 6/6 farm-origin 55–70 mm animals survived two types of injury while 5/6 survived a third type of injury. We then conducted a definitive study using 24 wild-origin animals (165–207 mm) and three intensified injury treatments. Five of six animals that received a deep tissue incision were dead the following morning, presumably from acute hemolymph loss, and the remaining animal in that treatment group died on day 41 with a systemic bacterial infection. Nine of twelve abalone that received loss of either 8% or 17% of foot sole epithelium survived until experiment termination at day 90, at which time all survivors were regenerating epithelial tissues, as evident by histology. This study suggests that abalone may be more capable of surviving significant superficial foot damage that can occur during collection and handling, at least in a captive rearing environment, than has been previously recognized.