Biological Characteristics and Feeding Dynamics of Indo Pacific Tarpon (Megalops cyprinoides Broussonet 1782) in Estuarine Waters of North Kalimantan, Indonesia

Abstract

The Indo-Pacific Tarpon (Megalops cyprinoides) is a species that has important ecological and economic value in tropical estuarine and coastal ecosystems, but information on its biology in Indonesian waters is still very limited. This study aims to analyze the size distribution, growth patterns, condition factors, and feeding habits of M. cyprinoides from Tanjung Palas, North Kalimantan, Indonesia. This research was a quantitative survey and analyzed using descriptive narrative methods. It was conducted from July to September 2025, with samples obtained from fishermen's catches at the Tanjung Palas fish landing site. The results showed that the total length of the fish ranged from 19.4-48.9 cm (35.12 ± 5.130 cm) with the highest frequency in the 36–38 cm size class (10.75%). The length-weight relationship showed a negative allometric growth pattern (b = 2.6827) with a strong correlation (r = 0.9780), which indicates that weight gain is slower than length gain. Condition factor values ​​ranged from 0.6516- 1.5618 (1.0860 ± 0.1621), reflecting variations in physiological status and the influence of the habitat environment. Stomach content analysis showed that shrimp, decapods, and aquatic insects dominated the main diet, while fish were only a supplementary component. The results of this study provide important information as a scientific basis for analyzing the population dynamics of this species in estuarine waters, and can support sustainable management and conservation efforts.