Restricted-movement paradigm: fish displacements in a small lowland streamlet

In a small lowland streamlet (width – 1.7 m, discharge ≤ 0.15 m³ s⁻¹, Central Poland) movements of six fish species were investigated in autumn, on three sampling occasions (2002–2004). The subject of the study were predominantly facultative riverine species (loach Barbatula barbatula (L.), gudgeon Gobio gobio (L.), perch Perca fluviatilis L., roach Rutilus rutilus (L.), giebel Carassius auratus (L.), tench Tinca tinca (L.)). For a few species the calculated median displacements (MD) were close or smaller than the home section lengths (HSL =100 m) with exception of giebel on one sampling occasion. These results were concise with estimated low turnover rate (TR) for the investigated species, which was significantly correlated with MD, and congruent with the Gerking’s restrictedmovement paradigm (RMP).