Movement Pattern and Habitat Use of the Endangered Brook Barbel (Barbus caninus) in a Mediterranean Stream

Understanding the ecology and behaviour of freshwater fish species is essential for effective management and conservation. Within the genus Barbus, small-sized mountain species remain understudied despite conservation concerns. In this study, we investigated the movement patterns, habitat use and flow preferences of the endangered species Barbus caninus in a Mediterranean mountain stream in northern Italy using passive integrated transponder telemetry. Over a 15-month period, 164 tagged fish were tracked between 2 and 30 times. Most individuals exhibited small home ranges, with a median linear range of 33.7 m, although a few fish moved over hundreds of metres. Fish size did not influence movement patterns. Movements were seasonally variable, with a significantly larger linear range observed during spring compared to other seasons. The barbel showed a weak preference for fast-flowing mesohabitats, and this preference was pronounced during winter. Despite this, B. caninus predominantly utilised low-velocity confined zones within hydromorphological units, potentially indicating energetically efficient microhabitat use. These findings shed light on the habitat requirements and movement patterns of an endangered species that inhabits small mountain streams and is subject to numerous anthropogenic threats.