Jurnal Iktiologi Indonesia

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. . — 2026-02-01

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

Navida Vinca Hanif — 2026-02-01

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.

Biodiversity of Ichthyofauna in The Pabelan River, Magelang Regency

Astuti Astuti — 2026-02-01

Pabelan River is one of the most important rivers in Magelang Regency. This research aims to determine the diversity and composition of the ichthyofauna in the Pabelan River, Magelang Regency. The research was conducted from August to October 2025 at three observation stations selected through purposive sampling. Fish were caught using nets with a mesh size of ¾ inch and a diameter of 4 meters. Sampling was conducted over eight weeks, twice a week, from 08.00-14.00 WIB, for two hours at each research station. Data analysis was conducted using the Shannon-Wiener diversity index (H’), Evenness uniformity index (E), and Simpson dominance index (C). The results show that there are 13 fish species classified into 8 families and 4 orders, with the order Cypriniformes being the most dominant. Ancistrus multispinis is recorded as the overall dominant species (RA 43.6%), but it was only found at the settlement station. The average length distribution of the fish was dominated by small fish (<10 cm), accounting for more than 50%. Meanwhile, the average weight percentage of fish sized <10 gs was more than 38%. The diversity index value (H’) obtained ranged from 0.81 to 1.73, the evenness index (E) from 0.35 to 0.83, and the dominance index (C) from 0.20 to 0.65. Environmental parameters indicate temperatures of 25.9–26.7 °C and a pH of 7.25–7.49, within the range that supports freshwater fish life. Meanwhile, the physical conditions of the water show a current speed of 0.31–0.73 m/s, a brightness of 8.8–11.6 cm, a depth of 43–59 cm, and a width of 17.3–29.2 m. Overall, the diversity of ichthyofauna in the Pabelan River is classified as moderate, with environmental conditions that still support freshwater fish.

Fish Species Diversity in The Krasak River Srumbung Subdistrict Magelang Regency Central Java

Maryam Tirta Nuur — 2026-02-01

This research aims to explore the diversity of fish species in the Krasak River, Central Java, where information on fish composition is still limited, in contrast to the Progo River and Elo River, which have been studied by several researchers. This river, originating from the slopes of Mount Merapi, has water characteristics with volcanic material and variations in current and substrate. The research was conducted from October to November 2025 at three observation locations using purposive sampling. All the fish caught were identified to the species level, counted for their individual numbers, and analysed using the Diversity Index (H'), Evenness Index (E), Dominance Index (D), and Relative Abundance (RA). Environmental parameters, including temperature, pH, current, depth, brightness, and substrate, were also measured as supporting data. The results show that the fish community in the Krasak River comprises 221 individuals across 12 species and 6 families. The Diversity Index shows low values (0.647-0.882), and the Evenness Index is also low (0.260-0.355), indicating an uneven distribution of individuals among species. The species Mystacoleucus obtusirostris became the dominant species, accounting for 53.39% of the total individuals captured. This study provides an initial overview of fish diversity in the Krasak River and is expected to be useful for fisheries resource management and further research.

Diet Composition and Feeding Habits of the Gobiid Fish Eleotris fusca in the Ummiding River, Polewali Mandar, West Sulawesi

Adiara Firdhita Alam Nasyrah — 2026-02-01

Eleotris fusca is one of the amphidromous goby fishes lives in Ummiding river, West Sulawesi. Amphidromous goby has a complex life cycle compared to other fishes. The adults lives in river for growth and reproduction, meanwhile the eggs and larvae are transported downstream to the estuary. After completing their larval development, they migrate back to freshwater. The presence of prey strongly influences the migration and growth of E. Fusca in nature. This study aims to reveal the diet composition and feeding habits of E. Fusca. Sample collected using an electrofishing unit in Ummiding river, West Sulawesi, throughout three months from October to December 2023. A total of 90 fishes captured with total length range 32-81 mm. The diet composition of E. fusca consisted in three types of prey, such as insect larvae, phytoplankton and zooplankton. Ratio of length intestinal explained E. fusca category as carnivorous and tends to has feeding strategy in generalist with the dominant prey Hemiptera from insect larvae.

Reproductive Biology of the Goby Sicyopterus longifilis from the Matama River, West Sulawesi, Indonesia

Tikawati Tikawati — 2026-02-01

Sustainable fisheries management depends heavily on the reproductive biology of amphidromous fishes, yet little is known about the reproductive traits of Sicyopterus longifilis. In this study, we determined gonad development stages in S. longifilis from the Matama River in West Sulawesi, Indonesia, macroscopically, following Effendie (1979), and calculated GMI from gonad weight and total body weight. From July to December 2023, we sampled fish monthly using an electric shocker. We measured egg diameter with an ocular micrometer under a compound microscope, evaluated fecundity using the gravimetric method, determined gonad development stages macroscopically according to Effendie (1979), and computed GSI from gonad and body weight. A total of 758 specimens, comprising 281 male and 477 females, were examined. Throughout the investigation, we found five gonad maturity stages (I-V), indicating ongoing reproductive growth. The peak reproductive activity occurred in July, and female GMI increased with gonadal development, reaching its highest value at GMS IV. Egg diameter varied from 0.20 to 0.44 mm, and fecundity varied from 43 to 7,887 eggs, with an average of 1,702 ± 2,551 eggs. S. longifilis appears to have a complete spawning strategy based on the unimodal distribution of egg diameter. The relationships between fecundity and total length, body weight, and gonad weight were relatively weak, indicating that reproductive output is influenced not only by fish size but also by environmental conditions and physiological status. These findings provide the first comprehensive information on the reproductive biology of S. longifilis in the Matama River and contribute essential baseline data for the conservation and sustainable management of amphidromous goby populations in West Sulawesi.

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. . — 2026-02-01