Social facilitation of learning in mixed‐species schools of common carp Cyprinus carpio L. and Nile tilapia Oreochromis niloticus (L.)

Abstract

The process of learning to associate a visual cue with food was studied in groups of common carp Cyprinus carpio and Nile tilapia Oreochromis niloticus by means of a classical conditioning paradigm. In the first phase of the study, fishes were conditioned in either single-species or mixed-species groups to associate a blinking blue light with food. In the second phase, group composition was altered so that only single species were reconditioned, composed of individuals previously paired with the same or the other species. In the first phase, in the single-species groups, Nile tilapia rapidly formed an association between the visual cue and food, whereas common carp failed to do so. In mixed-species groups, both Nile tilapia and common carp associated a visual cue with food. In the second phase of the study, Nile tilapia retained that ability irrespective of whether they had previously been trained in single-species or mixedspecies groups, common carp previously trained with Nile tilapia, were not repelled by the blinking blue light and gradually approached it from a distance, whereas common carp previously trained in homogenous groups continued to be repelled by the blinking light. Fish arrivals and departures from the feeding zones as well as fish position in the testing apparatus were analysed and contrasted in single-species and mixed-species groups outside the training sessions, revealing mutual impacts of one species on the other in mixed-species groups. The findings of this study demonstrated interspecific social facilitation of learning to associate a visual cue with food.

Temperature-Specific Competition between Invasive Mosquitofish and an Endangered Cyprinodontid Fish

“…For example, closer contact may be necessary to inspect a potential predator and hence assess the degree of threat [35], [36]. Alternatively, approaching other individuals may simply be a result of a predisposition for schooling behavior, as mixed species shoals are not uncommon [37], [38]. Whatever the purpose of this behavior, it is clear that toothcarp exhibited increased activity relative to mosquitofish at lower temperatures.…”

Behaviour of proactive and reactive tilapia Oreochromis niloticus in a T-maze

“…This observation could be due to the size and colour of the landmarks used (small and grey). Karplus et al (2007) showed that tilapia and carp (Cyprinus carpio) trained for 30 days had positive results at associative learning. Mazeroll and Montgomery (1998) demonstrated that when using marks as guides to feeding routes for doctorfish (Acanthurus chirurgus), the fish had to stop and analyse the novel environment and find the familiar mark.…”

A conditioned response overrides social attraction in common carp: A possibility for low stress sorting strongly schooling fish?

“…Preferential use of the rewarded trigger was strongest for fish trained with the red light and weakest for those trained with the blue light. In a study in which mixed groups of common carp and Nile tilapia (Oreochromis niloticus) were trained to associate a flashing blue light with food, the tilapia learned quickly to approach the light to receive food whereas the carp failed to do so, apparently because the carp were alarmed by this stimulus (Karplus et al, 2007). A preference for red stimuli in the context of feeding has been demonstrated for several species of fish (e.g.…”