The nature and role of learning in the orientation and migratory behavior of fishes

Abstract

SynopsisFish migration may be viewed as the product of two processes; the selection and tracking of optimal environmental conditions through time and space, and the use of predictive information about environmental structure to bias movements towards a goal. The establishment and maintenance of directional bias is based on the interaction of experience and instinct. The preoccupation of much fish orientation research with innate fixed patterns of behavior on one hand and hydrodynamics on the other has led us to underestimate the possibility that orientation is a flexible process relying on developmental sequences, calibration of the motor-sensory interaction based on experience and the learning of environmental pattern. Evidence illustrating how experience and learning may influence the direction of movement and how the goal is recognized is presented according to two general categories: (a) imprinting and early experience and (b), spatial learning, including the social transmission of migratory routes and directions. In the first category, the olfactory hypothesis of salmon homing is briefly reviewed and new data presented describing olfactory imprinting in Atlantic salmon, Salmo salar. In the second category, evidence is presented demonstrating the modifiability of sun-compass orientation and the ability of some fish species to learn the spatial distribution of landmarks. The role of social transmission in the migration of coral reef fishes is reviewed. The possible role of these learning phenomena in the formation of familiar area maps, route-based and location-based navigation and the critical distance factor is considered. The relationship between life history and the nature of learning in migratory orientation is discussed.

Active migration of wild Atlantic salmon Salmo salar smolt through a coastal embayment

“…For example, smolt actively swam against inflowing currents but did not actively swim against outflowing currents; smolt swam strongly against a positive salinity gradient but did not reverse their behaviour when there was a negative salinity gradient. These observations are consistent with the hypothesis that smolt exploit an innate compass to maintain a preferred bearing (reviewed in Dodson 1988). …”

Performance of goldfish trained in allocentric and egocentric maze procedures suggests the presence of a cognitive mapping system in fishes

“…Aronson, 1951Aronson, , 1971Reese, 1989;Teyke, 1989). This cognitive mechanism could be relevant for fish for traveling in their natural habitat, especially for species that are relatively site attached, such as goldfish and common carp (Reynolds, 1983), or for those that perform repeated migrations to different areas of their habitat (Dodson, 1988;Reese, 1989). Certainly, such a cognitive system would permit flexible and adaptive spatial behaviors, such as those observed here.…”

“…Research in this field has been focused mainly on the innate fixed patterns of behavior and on sensory, ecological, and zoological factors. What seems to be underestimated in this research, though, is the possibility that spatial behavior is a flexible process that involves learning and memory mechanisms and cognitive phenomena (for a review, see Dodson, 1988). Such mechanisms are indicated by a number of naturalistic and experimental studies, such as the pioneer work of Aronson (1951Aronson ( , 1971) that showed that the gobiid fish Bathygobius soporator uses learned information about the spatial relationships of tide pools, or topographical memories acquired during exploration, to orient itself accurately.…”

Season and site fidelity determine home range of dispersing and resident juvenile Greenland cod Gadus ogac in a Newfoundland fjord

“…Specific populations of adult Atlantic cod have been characterised as resident, homing, or dispersing (Robichaud & Rose 2004, Neat et al 2006. Site fidelity or homing patterns can vary across life stages in response to increased opportunity for spatial or social learning, depending on habitat stability (Dodson 1988, Odling-Smee & Braithwaite 2003 or body condition (Comeau et al 2002). These varying patterns affect the contributions of movements of individual fishes to population connectivity.…”