PLATINUM The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservaton globally by publishing peer-reviewed artcles OPEN ACCESS online every month at a reasonably rapid rate at www.threatenedtaxa.org. All artcles published in JoTT are registered under Creatve Commons Atributon 4.0 Internatonal License unless otherwise mentoned. JoTT allows unrestricted use, reproducton, and distributon of artcles in any medium by providing adequate credit to the author(s) and the source of publicaton. Journal of Threatened Taxa Building evidence for conservaton globally www.threatenedtaxa.org ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) Communication Length-weight relationships of two conservation-concern mahseers (Teleostei: Cyprinidae: Tor) of the river Cauvery, Karnataka, India Adrian C. Pinder, Rajeev Raghavan, Shannon D. Bower & J. Robert Briton 26 July 2020 | Vol. 12 | No. 10 | Pages: 16257–16261 DOI: 10.11609/jot.6201.12.10.16257-16261 For Focus, Scope, Aims, Policies, and Guidelines visit htps://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-0 For Artcle Submission Guidelines, visit htps://threatenedtaxa.org/index.php/JoTT/about/submissions#onlineSubmissions For Policies against Scientfc Misconduct, visit htps://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-2 For reprints, contact <[email protected]> The opinions expressed by the authors do not refect the views of the Journal of Threatened Taxa, Wildlife Informaton Liaison Development Society, Zoo Outreach Organizaton, or any of the partners. The journal, the publisher, the host, and the part- Publisher & Host ners are not responsible for the accuracy of the politcal boundaries shown in the maps by the authors. Member Threatened Taxa Journal of Threatened Taxa | www.threatenedtaxa.org | 26 July 2020 | 12(10): 16257–16261 ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) PLATINUM OPEN ACCESS DOI: htps://doi.org/10.11609/jot.6201.12.10.16257-16261 #6201 | Received 21 May 2020 | Final received 23 June 2020 | Finally accepted 20 July 2020 C o m Length-weight relatonships of two conservaton-concern mahseers m u n (Teleostei: Cyprinidae: Tor) of the river Cauvery, Karnataka, India i c 1 2 3 4 a Adrian C. Pinder , Rajeev Raghavan , Shannon D. Bower & J. Robert Briton t i 1,4 Faculty of Science and Technology, Bournemouth University, Poole, BH12 5BB, UK. o 1,2 Mahseer Trust, c/o Freshwater Biological Associaton, East Stoke, Wareham, Dorset, BH20 6BB, UK. n 2 Department of Fisheries Resource Management, Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, Kerala 682506, India. 3 Infnity SES, 507 McLeod St., Otawa, Ontario, Canada. 1 [email protected] (corresponding author), 2 [email protected], 3 [email protected], 4 [email protected] Abstract: Length-weight (LW) relatonships are presented for two conservaton-concern species of mahseer (Tor spp.) from southern India’s river Cauvery. Constructed from angler catch data, these are the frst available LW relatonships for the Critcally Endangered Tor remadevii and the non-natve and locally invasive Tor khudree. For T. remadevii, the value of b, the allometric parameter, was 2.94 (95% CI: 2.75–3.14) and was not signifcantly diferent from 3.0, indicatng isometric growth (t = 0.61, P = 0.54). For T. khudree, b was greater at 3.18 (95% CI: 3.01–3.38), but with this also not signifcantly diferent from 3.0 (t = 1.91, P = 0.06). Outputs are discussed with reference to species conservaton and recreatonal catch-and-release fsheries. Keywords: Angling, Critcally Endangered, invasive fsh, Tor khudree, Tor remadevii. Editor: Mandar Paingankar, Government Science College Gadchiroli, Maharashtra, India. Date of publicaton: 26 July 2020 (online & print) Citaton: Pinder, A.C., R. Raghavan, S.D. Bower & J.R. Briton (2020). Length-weight relatonships of two conservaton-concern mahseers (Teleostei: Cyprinidae: Tor) of the river Cauvery, Karnataka, India. Journal of Threatened Taxa 12(10): 16257–16261. htps://doi.org/10.11609/jot.6201.12.10.16257-16261 Copyright: © Pinder et al. 2020. Creatve Commons Atributon 4.0 Internatonal License. JoTT allows unrestricted use, reproducton, and distributon of this artcle in any medium by providing adequate credit to the author(s) and the source of publicaton. Funding: Pinder, Bower, and Raghavan’s partcipaton was supported by the Fisheries Society of the Britsh Isles and the Mahseer Trust. Bower was also funded by the Ontario Graduate Scholarship, Too Big to Ignore, and Mitacs Research Grant. Competng interests: The authors declare no competng interests. Author details: Adrian Pinder is based at Bournemouth University (UK) and is the Director of Research at the Mahseer Trust. He is a fsh ecologist with a special interest in the conservaton of threatened species. Rajeev Raghavan is interested in conservaton of aquatc biodiversity of Western Ghats with special reference to freshwater fshes. Shannon Bower’s primary area of research is fsh and fsheries, with an emphasis on recreatonal fsheries, social-ecological systems analysis, sustainable development, and partnerships. This work has taken her around the world, ofering insights into the role cultural systems and beliefs play in our relatonships with the world aquatc and the solutons we create to solve our problems. Rob Britton is a Professor at Bournemouth University. His research interests cover the impacts on aquatc fauna of anthropogenic stressors, including invasive alien species, habitat loss and climate change. Author contributon: All authors contributed equally to the study design and data collecton. ACP and JRB did the data analysis. ACP wrote the frst draf. All authors contributed equally fnalizing the manuscript Acknowledgements: The authors wish to thank Naren Sreenivisan and the Wildlife Associaton of South India (WASI) for the provision of angler catch data from the Cauvery Wildlife Sanctuary. We thank Coorg Wildlife Society for access to their waters for sampling purposes and all the anglers’ who contributed to the collecton of data. We are also grateful to A. Harrison for assistance in the producton of Figure 1. 16257 J TT Length-weight relatonships of two conservaton-concern mahseers Pinder et al. INTRODUCTION assist the urgent conservaton of T. remadevii. Despite its global iconic status as a premier sport fsh and the largest growing of all mahseers (Tor spp.) MATERIALS AND METHODS (Pinder et al. 2019), the formal taxonomic identty of the mega-faunal Hump-backed Mahseer has untl recently Historic length-weight statstcs for T. remadevii were eluded ichthyologists since frst being brought to their recovered from the former angling camps and protected atenton in the 19th century (Jerdon 1849). Now known reaches of the middle River Cauvery that extend across to be endemic to the Cauvery River catchment (Pinder 24km between Doddamakali Nature Camp (12.3070N & et al. 2015a), recent research has confrmed this fsh to 77.2150E) and Mekedatu Gorge (12.2590N & 77.4470E), be conspecifc with Tor remadevii (Pinder et al. 2018a), Karnataka, India (Fig. 1). Data used in the analysis a species for which the formal descripton was based on date from 1976 to 1990 and were seasonally restricted 19 juvenile specimens collected from the river Pambar, between the months of December and May when river the southernmost tributary of the river Cauvery in fows are suitably reduced to allow the recreatonal Kerala, India (Kurup & Radhakrishnan 2007, 2010). Due fshery to operate. These fsh were captured by rod-and- to estmated populaton reductons in excess of 90% and line angling, with their fork lengths and weights recorded an extremely limited distributon range, T. remadevii before release. Lengths were measured using non-rigid was recently assessed as Critcally Endangered on the tape measures and weights from ‘spring-balances’. For IUCN Red List of Threated Species (Pinder et al. 2018b), the later, due to the combinaton of the size of some of making it the most imperilled of all Tor species. the fshes (> 40kg) and their recording in feld conditons, Introductons of T. khudree into the river Cauvery the weights were typically recorded to the nearest 250g. from the 1970s has been implicated in the collapse For T. khudree, length-weight data of individual fsh of the endemic T. remadevii populaton (Pinder et al. were collected from the upper river Cauvery (Ammangala 2015a; Pinder et al. in press). In recogniton of the non- Village, Valnur; 12.4570N & 75.9600E, in Kodagu District natve and invasive status of T. khudree outside its natve (Coorg), Karnataka, India (Fig. 1) during March 2014 and distributon range, India’s current Natonal Wildlife between February and April 2015. Captured using rod Acton Plan 2017–2031, includes the acton of actvely and line tactcs, the data for each fsh were recorded removing T. khudree from Cauvery, through angling or by trained fshery professionals. Fish lengths (FL) were other suitable means, to reduce the populaton of this recorded using a standard rigid measuring board (to undesirable species. This goes hand-in-hand with a 0.1cm) and weights recorded using a protectve weigh further recommendaton, that captve bred ‘orange- sling and a spring balance appropriate to individual fnned’ mahseer T. remadevii should be stocked to fsh size (models: Salter Super Samson 20kg/100g assist the recovery of this endemic species (Ministry and 5kg/25g). All fsh were released following their of Environment, Forests and Climate Change, 2017). processing. Furthermore,