Rizqi Soviyatul Wahidah, I Wayan Restu, Ni Made Ernawati

ASPEK REPRODUKSI IKAN NILEM (Osteochilus vittatus) YANG DITANGKAP DI SUNGAI WILAYAH MENGWI DAN ABIANSEMAL, KABUPATEN BADUNG, PROVINSI BALI

Introduction

Aspek reproduksi ikan nilem (osteochilus vittatus) yang ditangkap di sungai wilayah mengwi dan abiansemal, kabupaten badung, provinsi bali. Kaji reproduksi ikan Nilem (Osteochilus vittatus) di sungai Mengwi & Abiansemal, Bali. Analisis pertumbuhan, rasio kelamin, kematangan gonad, IKG, dan fekunditas ikan lokal.

Abstract

This study examines the reproductive aspects of Nilem fish (Osteochilus vittatus) in the Mengwi and Abiansemal Rivers, Badung Regency, Bali Province. The parameters analyzed include: length and weight relationship, sex ratio, gonad maturity level (TKG), gonad maturity index (IKG), and fecundity. The study was conducted in the Angantaka Village River, Abiansemal and the River in Abianbase Village in March and May 2025. The research method was quantitative descriptive with a total sample of 100 fish. The results showed: growth patterns were classified as negative allometric (length growth is more dominant than weight), a sex ratio of 3:2, with male fish dominance. Male fish were dominated by TKG I (immature gonads), while female fish were dominated by TKG IV (mature gonads). The highest average IKG value for males was 16.49 and for females 28.35. The average fecundity of female fish at station 1 was 68,732 eggs and at station 2 was 12,812 eggs.

Review

This study investigates the reproductive biology of Nilem fish (*Osteochilus vittatus*) in the Mengwi and Abiansemal Rivers, Badung Regency, Bali Province. Addressing a crucial gap in local fisheries research, this work provides foundational data on the species' reproductive aspects, which is essential for understanding population dynamics, informing sustainable management practices, and guiding conservation efforts in these specific riverine ecosystems. The parameters examined—length-weight relationships, sex ratio, gonad maturity, and fecundity—are comprehensive and relevant for such an ecological assessment. Employing a quantitative descriptive methodology on a sample of 100 fish, the study presents several key findings. The analysis revealed a negative allometric growth pattern, indicating that length growth is more dominant than weight. A male-dominated sex ratio of 3:2 was observed. Interestingly, while male fish primarily exhibited immature gonads (TKG I), female fish predominantly displayed mature gonads (TKG IV), with corresponding high average Gonad Maturity Index (IKG) values of 16.49 for males and 28.35 for females. Fecundity estimates showed considerable variation between sampling stations, with an average of 68,732 eggs at station 1 and 12,812 eggs at station 2. The study offers valuable baseline information on *Osteochilus vittatus* reproductive ecology, contributing meaningfully to the regional ichthyological literature. The detailed assessment of multiple reproductive parameters is a strength, providing a comprehensive snapshot of the population's status. However, a significant concern demanding immediate clarification is the stated study period of 'March and May 2025,' which strongly suggests a typographical error as it implies the research has not yet been conducted. Assuming this date is an error, the observed discrepancies in gonad maturity between sexes and the substantial variation in fecundity between stations highlight potential areas for future research, particularly regarding environmental drivers and spawning periodicity. Once this methodological clarity is addressed, the findings will be a solid contribution to the understanding and management of Nilem fish in Bali.

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