J Appl Ichthyol. 2018;1–2. wileyonlinelibrary.com/journal/jai | 1 © 2018 Blackwell Verlag GmbH 1 | INTRODUCTION The four snakeheads Channa andrao Britz, 2013, Channa aurantimaculata Musikasinthorn, 2000, Channa bleheri Vierke, 1991, and Channa stewartii (Playfair, 1876) are endemic to the Brahmaputra River drainage. Except for the distribution of C. stewartii in northeast India and Nepal, C. an- drao, C. aurantimaculata and C. bleheri have localized populations, mostly known from their type localities, West Bengal and Assam, northeast India respectively (Chaudhry, 2010; Froese & Pauly, 2018). Besides consumed as food fish, these channids have very high ornamental values in both domestic and overseas markets. Length–weight relationships (LWRs) are useful in fisheries science and can assist to assess the species status as well as characterize growth patterns provided the required associated parameters are also determined. However, LWRs data on C. andrao, C. aurantimaculata, C. bleheri and C. stewartii are limited. Therefore, the pres‐ ent study provides the LWRs report for these four snakehead species. 2 | MATERIALS AND METHODS Sampling was carried out seasonally (between February to mid‐May for Pre‐monsoon; mid‐May to August for Monsoon; September to November for Post‐monsoon; December to January for Winter) from October 2016 to May 2018 in the following sampling sites along the Brahmaputra River drainage, northeast India: Dibru River at Laika (27°41ʹ14ʺ N; 95°20ʹ60ʺ E) for C. aurantimaculata and C. stewartii; Rupahi beel (wetland) at Morigaon (26°31ʹN; 92°15ʹE)for C. stewartii; Sonkosh River at Jamduar (26°43ʹ59ʺ N; 89°51ʹ39ʺ E) and Chaudhuri ghat (26°39ʹ04ʺ N; 89°42ʹ24ʺ E) for C. andrao and C. bleheri. A catch‐ and‐release policy was maintained throughout the study period due to rarity of the species. A total of 150 fish (C. andrao: 41; C. auran- timaculata: 30; C. bleheri: 18; C. stewartii: 61) were caught with the help of local fishermen using cast nets (mesh size: 10–20 mm), scoop nets (mesh sizes: 05–20 mm) and bamboo traps; transferred imme‐ diately to portable plastic tanks; total length measured (nearest to 0.1 cm) and weighed (nearest to 0.1 g) carefully with minimal stress to the fish and released back to the water body. Fishing nets were employed for an average of 8–10 times per sampling site, while bam‐ boo traps were placed overnight and the lured fish (if any) were col‐ lected the next morning. LWRs were calculated following the regression expression: log TW =log a + b log TL with 95% confidence limits of the constants (“a” and “b”). Log‐log plots of length and weight values were performed to remove outliers (Froese, 2006). Received: 3 July 2018 | Revised: 25 August 2018 | Accepted: 5 September 2018 DOI: 10.1111/jai.13804 TECHNICAL CONTRIBUTION Length‐weight relationships of four endemic snakeheads [ Channa andrao Britz, 2013, Channa aurantimaculata Musikasinthorn, 2000, Channa bleheri Vierke, 1991, and Channa stewartii (Playfair, 1876)] from the Brahmaputra drainage, northeast India Minakshi Kalita | Hrishikesh Choudhury | Anu Saikia | Dandadhar Sarma Department of Zoology, Gauhati University, Guwahati, India Correspondence Dandadhar Sarma, Department of Zoology, Gauhati University, Guwahati, Assam, India. Email: sarma_dandadhar@yahoo.com Funding information University Grants Commission Abstract The paper provides the Length–weight relationships (LWRs) for four endemic snake‐ head fish species namely Channa andrao Britz, 2013, Channa bleheri Vierke, 1991, Channa aurantimaculata Musikasinthorn, 2000 and Channa stewartii (Playfair, 1876), based on seasonal catches along the Brahmaputra river drainage from October 2016 to May 2018, using cast net (mesh size: 10–20 mm), scoop net (mesh size: 05–10 mm) and bamboo traps. Total lengths (TL) (nearest to 0.1 cm) and body weights (nearest to 0.1 g) were taken respectively. The b values in the LWRs were 3.26 for C. andrao, 2.74 for C. bleheri, 3.04 for C. aurantimaculata, and for 2.78 C. stewartii respectively. For C. aurantimaculata (=36.2 cm), C. bleheri (=14.4 cm) and C. stewartii (=29.7 cm) each, a new maximum total length (TL) was recorded.