Tarpon Prochiludos

Exhibits a robust, laterally compressed body with an elliptical profile, characterized by an olive-green or grayish dorsal coloration that transitions to bright silvery tones along the flanks and belly. It features medium-sized cycloid scales arranged in longitudinal rows, creating subtle dark lines running along the flanks. The head is moderate in size with a highly specialized terminal mouth, equipped with thick, fleshy lips modified into a suctorial disc containing rows of tiny, movable, spade-like teeth. Adults typically reach average lengths of 50 to 60 centimeters, although exceptional specimens can achieve up to 80 centimeters in standard length and weigh over 6 kilograms. The dorsal and caudal fins display a pattern of dark transverse bands alternating with lighter zones, with a relatively short anal fin and a deeply forked caudal fin.

Geographical distribution: Is natively distributed throughout the La Plata basin, a vast South American river system encompassing territories within Argentina, Bolivia, Brazil, Paraguay, and Uruguay. It is particularly abundant in the main channels and tributaries of the Paraná, Paraguay, Uruguay, and Río de la Plata rivers. Additionally, the species has colonized or been anthropogenically introduced into several adjacent sub-basins and reservoirs in Brazil, such as the Paraíba do Sul river basin.

Habitat: Prefers freshwater lotic and lentic ecosystems, showing outstanding adaptability to main river channels, floodplains, marginal lagoons, and wetlands. It is closely associated with soft bottoms composed of silt, clay, and abundant decomposing organic matter. This taxon is highly tolerant of significant fluctuations in water turbidity, temperature, and dissolved oxygen levels, which are characteristic of seasonal flood pulses in large South American river basins.

Feeding: Categorized trophically as an iliophagous and detritivorous organism, its diet relies almost exclusively on the ingestion of organic detritus, nutrient-rich mud, benthic microalgae, diatoms, and bacteria associated with the sediment. It uses its specialized suctorial mouth and highly adapted gill rakers to filter and scrape riverbed sediments, efficiently assimilating the organic fraction while expelling inorganic particles, thereby playing a pivotal role in the ecosystem´s nutrient cycling.

Behavior: Exhibits a highly migratory (potamodromous) behavior, performing massive upstream movements for reproduction and feeding, covering distances of up to hundreds of kilometers. It forms large, dense schools that navigate river systems in a coordinated manner. The species is well-known for its impressive ability to leap out of the water, especially when encountering physical barriers in the river channel or when startled by passing vessels. It acts as an ecosystem engineer by bioturbating and oxygenating benthic substrates during its constant foraging activities.

Reproduction: Employs a reproductive strategy of total spawning and external fertilization, with no parental care of any kind. The reproductive cycle is closely synchronized with rising water temperatures and increased river discharge during the spring and summer seasons. Adults migrate upstream to spawning sites in the main channels to release oocytes and sperm. The resulting eggs are semi-buoyant and non-adhesive, drifting downstream into nursery areas such as flooded plains and marginal lagoons, which provide rich food sources and vital shelter for developing larvae and juveniles.

Conservation status: Is classified under the category of Least Concern (LC) on the IUCN Red List of Threatened Species due to its wide geographical range and historically high abundance. However, local populations face severe anthropogenic threats, including commercial overfishing, chemical pollution of water bodies, and the fragmentation of migratory corridors caused by the construction of hydroelectric dams, which severely disrupt their natural life cycle.