FIN HEALING FOLLOWING INJURY OR SAMPLING

Fins may be damaged during handling or by tissue removal for ageing or genetic purposes. To assess how fins heal following different sampling techniques, three different pectoral fin ray treatments were applied to Atlantic sturgeon Acipenser oxyrinchus oxyrinchus (n=8-9 fish/trt): entire leading fin ray removed, a 1-2 cm portion removed near the point of articulation or a 1-2 cm portion removed from a secondary fin ray. All fish were given an injection of an oxytetracycline-based antibiotic into the dorsal musculature following fin treatments, except for an additional group (n=8) that had the entire fin spine removed to assess effects on healing. Following fin section removal, fish from different treatments were mixed equally between three large (4,000-L) recirculating systems, and fin ray healing and mortality were monitored over a 12-month period. To assess healing, blood samples were collected at 4 months to measure immune system responses, radiographs were taken at 4, 8 and 12 months to assess the degree of calcified structure healing and fin rays were analyzed histologically at the conclusion of the study. Survival was high in all treatments, and healing progressed differently depending on the treatment, with the slowest healing observed in fish with the entire fin spine removed. Radiograph and histological sampling revealed insight into how fin rays heal following injury.