The ethical and humane treatment of animals farmed for human consumption has been a topic of concern among public and scientific stakeholders for decades. These discussions have historically focused on issues pertaining to terrestrial livestock, with little interest directed towards aquacultured species. Recent studies investigating the possibility of sentience in decapod crustaceans has provided a platform for the topic of humane harvest of crustaceans to enter mainstream discourse in both the public and political realms. This has led several countries to implement policies addressing ethical concerns related to decapod slaughter; examples include Norway’s ban on slaughter of crustaceans prior to stunning in 2018, bans on boiling lobsters alive in New Zealand, Italy, and Switzerland, as well as the United Kingdom’s recognition of decapod crustaceans as sentient creatures in 2021. As dialogue and research in this field continues to expand, efforts to minimize nociception and suffering during the slaughter process are also ongoing.
Humane methods of slaughter typically strive to dispatch animals quickly to minimize pain, suffering, and fear. However, many dispatching methods developed for decapod crustaceans prioritize quality of the product over welfare. Use of substances that diminish an animal’s ability to perceive noxious stimuli or lower the individual’s ability to experience discomfort are an accepted practice in other food animal industries. Thus, loss of sensibility through use of anesthetics or sedatives is a simple practice that could be incorporated into the harvest process to ensure welfare standards while simultaneously preserving meat quality. The purpose of this study is to identify an ideal drug and method of use that could be implemented prior to slaughter.
A series of pilot trials were conducted using three “anesthetic” compounds to identify the minimum dose required to elicit a sedative or anesthetic response in Florida stone crabs (Fig. 1). Individuals were placed in anesthetic baths and reflex scores were assessed using a modified reflex action mortality predictor (RAMP) that measured voluntary and involuntary responses. Using quantifiable metrics, reflexes were scored on a scale of 0 to 3 with three denoting typical response behaviors, the two intermediary scores being weak responses and zero representing the complete absence of a response. Each reflex was measured every two minutes for a maximum of one hour prior to the subject being transitioned to a recovery tank. Future expansion of this study will consider dosing modifications, evaluation of several physiological responses and increased replication.