Morphological and Morphometric Characteristics of Otolith Tinfoil Barb (Barbonymus Schwanefeldii Bleeker, 1854) in The Kamijoro Dam, Kulon Progo Regency

Abstract

The Tinfoil barb (Barbonymus schwanefeldii) is a freshwater fish in the family Cyprinidae, commonly found in Southeast Asia, including the waters of the Kamijoro Dam in Yogyakarta. This study aims to analyse the morphological and morphometric characteristics of the otoliths of Tinfoil barb across fish size classes. The study was conducted from October to December 2025. A total of 267 Tinfoil barb samples were collected and grouped into three size classes: small (8.5 – 14.9 cm), medium (15.0 – 18.9 cm), and large (19.0 – 29.0 cm). The otoliths used were of the sagitta type, and the following parameters were measured: length, width, area, perimeter, weight, and six otolith shape indices. The result showed that Tinfoil barb otoliths are asymmetrically elliptical in shape with a heterosulcoid sulcus type. All analyzed otolith morphometric parameters showed a significant increase as fish body size increased (p < 0.001). The small-sized group showed mean values for the OL, OW, OA, OP, and OWt parameters of 0.282 ± 0.044 cm; 0.219 ± 0.030 cm; 0.042 ± 0.012 cm²; 0.933 ± 0.149 cm; and 0.002 ± 0.001 g. The medium-sized class had mean values for OL, OW, OA, OP, and OWt parameters of 0.352 ± 0.037 cm; 0.261 ± 0.021 cm; 0.060 ± 0.010 cm²; 1.176 ± 0.125 cm; and 0.004 ± 0.001 g. The large size class showed average values for OL, OW, OA, OP, and OWt of 1.518 ± 6.000 cm; 1.383 ± 6.023 cm; 1.152 ± 6.063 cm²; 2.719 ± 5.813 cm; and 1.036 ± 6.084 g. The relationship between fish length and otolith parameters was positive, with a coefficient of determination value ranging from indices that reflect ontogenetic changes, namely a decrease in roundness, form factor, and rectangularity, as well as an increase in circularity, aspect ratio, and ellipticity, indicating a change in shape from a transparent, round form to a more elongated, compact, and complex one.