The Relationship Between Journal Classification and the Use of Anesthesia Considering Fish Welfare

Anesthesia is used not only to immobilize fish but also to prevent them from experiencing unnecessary pain or distress.Anesthesia is widely used in fish research in Japan, but little information is available on its actual use.This study aimed to investigate the use of anesthesia in Japanese fish research through a literature review, and to examine the relationship between journal classifications and actual usage patterns from an animal welfare perspective.The literature review covered domestic research using anesthesia on fish from 2019 to 2024, and recorded information on anesthesia methods and post-anesthesia procedures.The results showed that the most frequently used anesthetic was eugenol.This is likely because eugenol was the only anesthetic legally approved for use in research involving fish for consumption at the time.However, when looking at literature published in overseas academic journals, 2-phenoxyethanol was the most commonly used anesthetic.These studies tended to focus on fish not for consumption, and the use of 2-phenoxyethanol, which has a rapid introduction and recovery of anesthesia, may have been preferred.On the other hand, Japanese literature tended to contain invasive procedures such as dissection using anesthetic methods with inadequate pain management.This is thought to be partly due to the tendency to include few animal welfare-related descriptions in academic journal guidelines in Japan.Overall, this review found that researchers tend to use anesthesia not to improve the welfare of the fish, but to comply with regulations or journal guidelines.