Feeding habits and diet overlap between Delminichthys ghetaldii and Telestes dabar, two endemic species from karst poljes in Bosnia and Herzegovina

Abstract

This study presents primary observations of the natural diet of two endemic fishes, Delminichthys ghetaldii and Telestes dabar, along with an examination of their niche overlap. The feeding habits of these species were analyzed based on a dataset comprising 115 specimens collected from five karst poljes during the year 2018. Statistical analyses, including one-way ANOVA and Tukey’s HSD post-hoc testing, were employed to discern significant differences in body size and weight among the five populations of Delminichthys ghetaldii. Numeric indices such as numerical abundance, weight percentage of abundance, and frequency of occurrence, alongside a composite index (IRI - index of relative importance), were applied to elucidate the feeding strategy of these species. The diversity of diet and poljes utilization was assessed using Simpson’s diversity index, while predation selectivity was analyzed through the electivity index. Considerable overlap in the diet of Delminichthys ghetaldii was observed among the five poljes, as well as in the overlap between these two species. The findings of this study indicate that Delminichthys ghetaldii exhibits a zoophagous planktivorous diet, i.e. carnivorous, while Telestes dabar demonstrates a phytofagous planktivorous diet, i.e. herbivorous.

Keywords

• Endemic minnows
• feeding niche
• karstic poljes
• selectivity
• semi-troglodytic