The Geometric World of Fishes: A Synthesis on Spatial Reorientation in Teleosts

Abstract

Fishes navigate through underwater environments with remarkable spatial precision and memory. Freshwater and seawater species make use of several orientation strategies for adaptative behavior that is on par with terrestrial organisms, and research on cognitive mapping and landmark use in fish have shown that relational and associative spatial learning guide goal-directed navigation not only in terrestrial but also in aquatic habitats. In the past thirty years, researchers explored spatial cognition in fishes in relation to the use of environmental geometry, perhaps because of the scientific value to compare them with land-dwelling animals. Geometric navigation involves the encoding of macrostructural characteristics of space, which are based on the Euclidean concepts of "points", "surfaces", and "boundaries". The current review aims to inspect the extant literature on navigation by geometry in fishes, emphasizing both the recruitment of visual/extra-visual strategies and the nature of the behavioral task on orientation performance.

Keywords: fishes; navigation; reorientation; spatial geometry; teleosts.

Figure 1

Within a rectangular white room, the corner with the box has a long surface on the left and a short one on the right (metric and sense attributes). The same is true for the location that is 180° rotationally symmetric corner. These two corners are geometrically identical, and the other two corners are characterized by opposite geometry (a long surface on the right and a short one on the left).

Figure 2

The geometric symmetry in (a) can be resolved by providing distinctive nongeometric cues. In (b), one of the two long surfaces has been painted in blue, and the correct corner can be identified by integrating the geometry with the landmark (i.e., the target corner has a long blue surface to its left). In (c), each corner has a distinctive pattern/color, and the local landmark itself is enough to identify the target (i.e., the corner with the box is lime-gray patterned).

Figure 3

The figure shows the rectangular transparent arena adapted for the nonvisual rewarded exit task (a). Four corridors were placed at the corners – two with a large central slit that fish could exit through (correct-geometry diagonal corners) and the other two with smaller slits that fish could not swim through (b).

Figure 3

The figure shows the rectangular transparent arena adapted for the nonvisual rewarded exit task (a). Four corridors were placed at the corners – two with a large central slit that fish could exit through (correct-geometry diagonal corners) and the other two with smaller slits that fish could not swim through (b).