Feeding ecology of two sympatric Cyprinidae, Sarmarutilus rubilio (Bonaparte, 1837) and Scardinius erythrophthalmus (Linnaeus, 1758) in Sidi Salem reservoir (Tunisia)

The provided information outlines a study conducted on the diet and feeding relationships of two species, Sarmarutilus rubilio (near threatened) and Scardinius erythrophthalmus, in the largest water reserve in Tunisia, Sidi Salem. Both species are introduced and are the most abundant in the reservoir. They share the same food resources, with macrophytes being the primary component of their diet, especially for S. erythrophthalmus, Macrophytes accounting for 77.78% of its diet. The second most important prey category for both species is Arthropoda. Additionally, there are other prey categories such as Cyanobacteria, Microalgae, Nematoda, and Sand, but these are ingested by both species in lower proportions (%PV < 1.5). S. rubilio, outside its native area, maintains its feeding plasticity The study revealed some differences in the diet of the two species. For S. erythrophthalmus, variations in diet were observed among seasons, while for S. rubilio, variations were observed among different stations within the reservoir. Both species were found to have narrow niche breaths, indicating specialized feeding habits. Despite these variations, the diets of the two species showed significant overlap. The research highlights the feeding ecology of S. rubilio and S. erythrophthalmus outside their native range. This information can be valuable for developing future fishery management plans and biodiversity preservation strategies in Tunisian freshwater systems. Understanding the feeding preferences and interactions between these introduced species can aid in maintaining a balanced ecosystem and conserving the native species in the region. Considering that S. rubilio is categorized as near threatened, such knowledge becomes even more crucial for effective conservation efforts.