Technical contribution Length–weight relationships of seven fish species from the upper Pelus River, Kuala Kangsar district, Perak, Malaysia By M. E. M. Ikhwanuddin 1 , M. N. A. Amal 1 , S. Shohaimi 1 , A. Azizul 1 , S. Johari 1 , T. Abdullah 1 and N. R. Jamil 2 1 Department of Biology, Faculty of Science, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia; 2 Department of Environmental Sciences, Faculty of Environmental Studies, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia Summary Length–weight relationships (LWR) are reported for seven fish species from the upper Pelus River, Kuala Kangsar dis- trict, Perak, Malaysia. This river is located in a remote area and supplies fishes for the aboriginal peoples. Fish samplings were conducted in three different seasons, the dry (June 2014), wet (August 2014), and moderately wet (April 2015). All samples were collected using fish electro–shocker and scoop nets with a 1 cm mesh size. A total of seven LWRs were unknown to FishBase, and four new maximum fish lengths were identified in the study. Introduction The Pelus River basin is a subcatchment of the larger area of the upper Perak River, which flows from its source near the border with Thailand southward through Perak state in Malaysia. Total catchment size and length of the Pelus River are estimated at 170 km 2 and 17 km, respectively. The rivers of this catchment are relatively short courses, with steep gra- dients in the upper courses. Some river reaches have a drop of more than 50 m, creating breath-taking waterfalls (Tori- man, 2010). The Pelus River also supplies fishes for local consumption, especially for the aboriginal populations along the river. For- est is the main land-use type in the area. Palm oil and rubber plantations are cultivated in the downstream area, while sun- dry cultivation can be seen along the upper part of the river (Toriman et al., 2008). The forest along the upper area of this river has recently come under threat due to extensive logging and land-clearing for plantation activity, which threatens the pristine water quality and fish populations in this isolated area. This paper describes the LWRs of seven fish species in the upper Pelus River, Kuala Kangsar district, Perak, Malaysia. Materials and methods Fish samplings were conducted in three different seasons: dry (June 2014), wet (August 2014), and moderately wet (April 2015). Three sites were chosen for fish sampling along the upper Pelus River (Site 1, lower site: 4°57 0 22.6″N; 101°15 0 06.1″E; Site 2, middle site: 4°56 0 16.5″N; 101°17 0 25.4″ Table 1 Descriptive statistics and estimated parameters of length–weight relationship (W = a L b ) for seven fish species from the upper Pelus River, Kuala Kangsar district, Perak. Family Species n Length range (cm) Weight range (g) a 95% Cl a b 95% Cl b R² Bagridae Batasio fluviatilis a (Day, 1888) 28 3.4–12.8 0.7–6.5 0.0323 0.0234–0.0446 2.44 2.278–2.598 0.974 Cyprinidae Barbodes binotatus a (Valenciennes, 1842) 16 3.7–11.6 0.4–16.8 0.00617 0.00401–0.0093 3.30 3.101–3.504 0.989 Crossocheilus atrilimes a (Kottelat, 2000) 36 6.6–16.4 1.8–32.7 0.00619 0.0046–0.0083 3.09 2.969–3.212 0.988 Devario regina a (Fowler, 1934) 58 1.4–10.1 0.1–11.2 0.0132 0.0100–0.0174 2.82 2.650–2.988 0.952 Neolissochilus hexagonolepis a (McClelland, 1839) 128 2.1–21.8 0.1–114.2 0.00998 0.0090–0.0110 3.04 2.979–3.091 0.989 Sisoridae Glyptothorax major a (Boulenger, 1894) 62 3.2–9.2 0.3–6.4 0.00745 0.0053–0.0103 3.15 2.963–3.334 0.959 Glyptothorax siamensis a (Hora, 1923) 23 6.3–13.9 2.0–24.7 0.00899 0.0064–0.0125 2.98 2.828–3.125 0.988 Bold = new maximum size; n, number of fish sample; total length (cm); total weight (g); a and b, relationship parameters; R 2 , coefficient of determination. a Data = first report on length – weight relationships. J. Appl. Ichthyol. (2016), 1–2 © 2016 Blackwell Verlag GmbH ISSN 0175–8659 Received: June 28, 2015 Accepted: September 23, 2015 doi: 10.1111/jai.13009 Applied Ichthyology Journal of