BIODIVERSITAS ISSN: 1412-033X Volume 21, Number 4, April 2020 E-ISSN: 2085-4722 Pages: 1279-1286 DOI: 10.13057/biodiv/d210402 Length-weight relationships and ponderal index of three reef fish (Teleostei: Labridae) off the Tanjung Tiram coast, Southeast Sulawesi, Indonesia ASRIYANA ASRIYANA 1,2,♥ , NUR IRAWATI 1 , HALILI HALILI 1 1 Department of Aquatic Resources Management, Faculty of Fisheries and Marine Sciences, Universitas Halu Oleo. Jl. HEA Mokodompit, Kampus Bumi Tridharma Anduonohu, Kendari 93232, Southeast Sulawesi, Indonesia. Tel. +62-823-4267-8801, ♥ email: asriyana@uho.ac.id 2 The Indonesian Ichthyological Society (IIS). Jl. Raya Jakarta-Bogor Km. 46, Cibinong, Bogor 16911, West Java, Indonesia Abstract. Asriyana A, Irawati N, Halili H. 2020. Length-weight relationships and ponderal index of three reef fish (Teleostei: Labridae) off the Tanjung Tiram coast, Southeast Sulawesi, Indonesia. Biodiversitas 21: 1279-1286. Parameters of length-weight relationship and ponderal index were estimated for first time for three reef fish (Labridae), Cheilinus trilobatus, Cheilinus chlorourus, and Choerodon anchorago, off the Tanjung Tiram coast, Indonesia. A total of 292 specimens (C. trilobatus 146 specimens; C. chlorourus 100 specimens; C. anchorago 46 specimens) were collected monthly in experimental gillnets in coral reefs and seagrass beds from January to June 2018. The length-weight relationship and ponderal index were calculated for each species. C. trilobatus showed total length and weight of 9.0-17.2 cm and 12.33-78.79 g, respectively, while C. chlorourus was 8.5-17.5 cm and 10.41-100.21 g, and C. anchorago 9.0- 27.0 cm and 18.51-414.00 g. C. trilobatus showed negative allometric growth, while C. chlorourus and C. anchorago had isometric growth. The length-weight relationship of C. trilobatus followed the linear equation of W=0.10TL 2.35 , while C. chlorourus and C. anchorago fit to W=0.03TL 2.83 ; W=0.03TL 2.91 respectively. The highest ponderal index occurred in May for C. trilobatus and in June for C. chlorourus and C. anchorago indicating a peak of the spawning season. The study results could be used as baseline information for future fisheries management of the area. Keywords: Growth pattern, isometric, Labridae, negative allometric, Southeast Asia INTRODUCTION Wrasses (Teleostei: Labridae) are reef-associated fishes among the dominant species in coral reefs (Meekan et al. 1995; Green 1996; Khalaf et al. 2005). Labridae is composed of at least 548 known species in 70 genera and considered as the second-highest in species diversity after Pomacentridae (Parenti and Randall 2018). Labridae is widespread along the coast of the Indian, Pacific and Atlantic Oceans (Nelson 1994; Helfman et al. 2009; Skiftesvik et al. 2014) and also represents a trophic major fish group in coral reefs (Setiawan 2010) known to clean dirt and biofouling on net in salmon commercial aquaculture (Kvenseth 1996) perform cleaning fish to control the attack of ectoparasite Lepeophtheirus salmonids (salmon lice) copepods in commercial Atlantic salmon culture (Salmo salar) and trout (Oncorhynchus mykiss) (Skiftesvik et al. 2014). Labridae is also known to have various trophic guilds and functional groups and fundamental roles in maintaining the health of coral reef systems (Cardozo-Ferreira and Joyeux 2016). Various species of Labridae are well distributed in Indonesia’s waters and are caught as by-catch in Scaridae (parrotfish) fisheries (Aswady et al. 2019, Dayuman et al. 2019). The important roles of Labridae in maintaining the health of coral reef ecosystems and fisheries require their exploitation to be regularly monitored to ensure its sustainability. One of the basic information that is currently lacking to support this management effort is about the relationship between the length-weight and the ponderal index. The length-weight relationship is very important in fisheries management since it can be to determining biomass by converting length measurements to weights, studying life history, comparing species growth between seasons and places, and assessing fish biology, physiology, ecology, and fisheries (Ricker 1975; Gonçalves et al. 1997; Moutopoulos and Stergiou 2002; Oscoz et al. 2005; Mimeche and Biche 2015). Information generated from length-weight relations can also be used to assess fish conditions and fish growth patterns, whether isometric or allometric (Zhu et al. 2008; Asriyana 2015; Hashim et al. 2017; Okomoda et al. 2018). The study of a fish population using ponderal index or condition factors is based on body length-weight analysis in which fish that is heavier with respect to its length is considered to be in healthier condition (Bolger and Connolly 1989; Asriyana et al. 2010; Asriyana 2015). There have been studies on Labridae larvae ecology (Victor 1986); age, growth, and reproduction (Hostetter and Munroe 1993; Donaldson 1995); eco-structure and spatial distribution (Hukom 1999; Locham et al. 2010); distribution, preference, habitat, and density (Dorf and Powell 1997; Skiftesvik et al. 2014, Rahman and Syam 2015); Phylogenetic (Westneat and Alfaro 2005) and community structure (Khalaf et al. 2005). Relationships of length-weight have been calculated for C. trilobatus (Letourneur 1998; Kulbicki et al. 2005, Gumanao et al. 2016), C. chlorourus (Letourneur et al. 1998, Kulbicki et Manuscript received: 7 September 2019. Revision accepted: 3 0DUFK 2020.