Journal of Fish Biology (2014) 84, 328–338 doi:10.1111/jfb.12287, available online at wileyonlinelibrary.com Evaluating the effectiveness of teeth and dorsal fin spines for non-lethal age estimation of a tropical reef fish, coral trout Plectropomus leopardus J.-P. A. Hobbs*†, A. J. Frisch‡, S. Mutz§ and B. M. Ford*‖ *The Oceans Institute and School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia, ‡ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld 4811, Australia, §School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia and ‖Centre of Excellence in Natural Resource Management, The University of Western Australia, Albany, WA 6330, Australia (Received 20 May 2013, Accepted 23 October 2013) This study investigated whether teeth and dorsal fin spines could be used as non-lethal methods of age estimation for a vulnerable and highly valued tropical fisheries species, coral trout Plectropomus leopardus . Age estimation of individuals from 2 to 9 years old revealed that dorsal spines represent an accurate ageing method (90% agreement with otoliths) that was more precise [average per cent error (APE) = 4·1, coefficient of variation (c.v.) = 5·8%] than otoliths (APE = 6·2, c.v. = 8·7%). Of the three methods for age estimation (otoliths, dorsal spines and teeth), spines were the most time and cost efficient. An aquarium-based study also found that removing a dorsal spine or tooth did not affect survivorship or growth of P. leopardus . No annuli were visible in teeth despite taking transverse and longitudinal sections throughout the tooth and trialling several different laboratory methods. Although teeth may not be suitable for estimating age of P. leopardus , dorsal spines appear to be an acceptably accurate, precise and efficient method for non-lethal ageing of individuals from 2 to 9 years old in this tropical species. © 2014 The Fisheries Society of the British Isles Key words: age determination; ageing; fisheries management; non-destructive; Serranidae; vulner- able species. INTRODUCTION Age estimation is important for calculating population parameters that are required for managing fisheries and conserving vulnerable species. Estimating the age of a fish typically involves counting increments (rings) on otoliths that have been usually produced by fluctuations in environmental conditions (Green et al., 2009). Obtaining otoliths requires collection and sacrifice of many individuals, which is undesirable for species of conservation, economic or recreational importance. Therefore, use of non-lethal techniques would be highly beneficial for estimating the age of vulnerable species or valuable fisheries targets. †Author to whom correspondence should be addressed. Tel.: +61 8 6488 4648; email: jean-paul. hobbs@uwa.edu.au 328 © 2014 The Fisheries Society of the British Isles