Largemouth Bass Micropterus salmoides, Florida Bass M. floridanus, and their intergrade are socially and economically valuable sport fish. In the southeastern United States, it is customary to age black bass (Micropterus) spp. using sagittal otoliths which requires killing the fish. Presently, fisheries managers and black bass anglers show reluctance to sacrifice large individuals. Development of a nonlethal ageing technique would not only allay concerns of sacrificing large black bass, but it could offer a pathway for new research, management, and conservation. We excised dorsal spines III–V from Largemouth Bass in Florida varying from 30–57 cm total length to evaluate the effects of the procedure on survival over 35 days. No mortalities were observed for fish with excised dorsal spines, and experiment-wide survival was 0.94 (0.87–1.00; 95% confidence interval). No significant differences in survival, weight change, or incidence of external injuries were observed between control and excised fish. The areas of spine excision healed with no visible infection or inflammation at the conclusion of the experiment. Therefore, dorsal spine removal offers managers a nonlethal option for collecting ageing structures of adult Largemouth Bass in Florida, including large individuals, and this result likely extends to other Micropterus spp. as well.

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