Fig. 1

Map of the study quadrat at a depth of 10–11 m. Black dots indicate the positions of Neolamprologus multifasciatus territories. Note that this cluster of N. multifasciatus territories was surrounded by a stretch of bare sand, at least one meter in width, separating it from the rest of the shell bed. Radiating circles represent radii of 0.5, 1, 1.5, and 2 m around an example territory, visualizing how we calculated neighbourhood density (see “Methods” section). Approximate cardinal directions and a measure of scale are indicated on the map