AACL Bioflux, 2020, Volume 13, Issue 1. http://www.bioflux.com.ro/aacl 167 Reproductive and morphometric characteristics of climbing perch Anabas testudineus in Sigi, Central Sulawesi, Indonesia 1 Samliok Ndobe, 1 Rusaini, 1 Abdul Masyahoro, 1 Novalina Serdiati, 1 Madinawati, 2 Abigail M. Moore 1 Aquaculture Study Program, Faculty of Animal Husbandry and Fisheries, Tadulako University, Palu 94118, Sulawesi Tengah, Indonesia; 2 Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar 90245, Indonesia. Corresponding author: S. Ndobe, samndobe@untad.ac.id Abstract . This study was part of a program oriented towards domestication of native freshwater fishes in Central Sulawesi, Indonesia, in particular the climbing perch ( Anabas testudineus, Bloch 1972). Previous studies have shown considerable variation between climbing perch populations, including in characters of importance for domestication. This study focussed on reproductive and morphological characters of the climbing perch population in Sigi District, specifically gonad maturity stage, gonadosomatic index (GSI), fecundity, length-weight relation ( W = aL b ), length-length relationship (SL = a+ b∙TL), Fulton's condition factor K and the meristic formula. Specimens ( n = 503) were collected in 2014, 2015 and 2019. Total length varied from 42 to 208 mm total length with body weight from 1.2 to 209.9 g. Overall sex ratio was balanced (1:1). The smallest specimens with mature gonads were: male TL = 72 mm; W = 8.1 g and female TL = 84 mm, W = 10.4 g. The condition factor K of males (mean ≈1.68) was generally lower than for females (mean ≈1.84); however the difference was not significant (p > 0.05). Fecundity, estimated using a gravimetric method, varied from 1,556 to 70,973, correlated positively and significantly with size (p < 0.001). The GSI of females in gonad maturity stage IV was high (mean 11.56%), significantly correlated with Fulton's condition factor K (p < 0.05) but not length or weight (p > 0.05). Gonad development patterns indicate a spawning peak during July-August. The meristic formula was D, XVIII+9; A, X+9; P, 13; V, I+5; C, 16. The length-weight relation showed isometric growth ( b≈3). The length-length relation (SL≈0.56+0.806 ∙TL) was highly significant (p < 0.001, R 2 = 0.984). Key Words: Anabantidae, gonad maturity, fecundity, meristic formula, length-weight relation. Introduction . Sulawesi is the largest island in Wallacea, a region renowned for its biodiversity, including freshwater fishes. However, to date freshwater aquaculture has largely concentrated on introduced species, rather than local (native) fishes. Many of these introduced species have proven capable of adapting to local conditions and can be considered invasive alien species. A program oriented towards the domestication of native fishes was initiated in the province of Central Sulawesi, Indonesia in 2013 (Ndobe et al 2013, 2014). Sigi District is the only land-locked district/city in Central Sulawesi, and has adopted freshwater aquaculture as a key development sector. The climbing perch ( Anabas testudineus Bloch, 1972) is a fish with a wide distribution in Asia (Froese & Pauly 2019), with Sulawesi thought to be the easternmost extremity of its natural range in Indonesia (Kottelat & Whitten 1996). It has suggested that the climbing perch was introduced to at least some inland waters (especially lakes) in Sulawesi by humans (Herder et al 2012; Kartamihardja 2014; Parenti et al 2014). However, the review by Thakur & Das (1986) considered it more likely that this fish crossed the Wallace Line naturally, aided by its tolerance to salt water, air breathing ability, and tendency to migrate between water bodies. It is possible that each of these hypotheses could apply to some Sulawesi climbing perch populations, as found in Japanese common carp (Mabuchi et al 2008) using mitochondrial DNA (mtDNA). The timing and mechanism(s) of climbing perch arrival in Sigi (and other regions within