The shoaling behavior of two cyprinid species in conspecific and heterospecific groups

Abstract

Mixed-species shoals of fish are frequently found in the field; however, little is known about individual-level interactions within these groups. We examined the collective motion of two cyprinid species (Chinese bream, Parabramis pekinensis, and qingbo, Spinibarbus sinensis) that occupy partially overlapping habitats but differ in social behavior (high vs low aggressiveness) and preferred flow regime (slow vs fast water velocity). We extracted measures of collective motion from video recordings of eight replicate groups of four individuals of either Chinese bream or qingbo (conspecific group) or two Chinese bream plus two qingbo (heterospecific group). Chinese bream in conspecific groups showed lower percent time moving and mean swimming speed but a similar speed while moving as compared to the qingbo conspecific groups. However, the difference in mean swimming speed and percent time moving vanished in the heterospecific group as Chinese bream elevated their swimming activity to coordinate with qingbo. This finding suggests that the two species may share similar interaction rules regarding shoaling behavior. The conspecific groups of qingbo exhibited a greater distance between group members than Chinese bream, suggesting a difference in cohesion. However, the inter-individual distances of all fish were similar in the heterospecific group. Qingbo in the heterospecific group swam more frequently at the front compared to Chinese bream, possibly due to their higher activity level. We also measured the startle response to an artificial stimulus and found that there was no significant difference among groups. In conclusion, the present study demonstrated that in the heterospecific groups, Chinese bream elevated their percent time moving while qingbo decreased their inter-individual distance to achieve consistent collective movement; thus, the two species showed similar behavior in the mixed-species group.

Density dependent attributes of fish aggregative behaviour

“…With a few exceptions, species were distinguishable in the videorecordings. Because of the presence of heterospecific schools, the data were not separated by species especially since there is an evidence that the species in the heterospecific groups adjust to each other (Tang et al, 2017). Moreover, size of heterospecific group probably undergoes different pressures and might be more easily dismissed (Wolf, 1985).…”

Biological Entanglement–Like Effect After Communication of Fish Prior to X-Ray Exposure

“…Fish are social organisms and a shoal is often described as a superorganism due to the level of coordination, which is thought to involve inter-fish communication by physical, chemical, or visual signals. 125 – 127 One explanation which has some merit is the idea that exposure to a small dose of a stressor after rather than before a large dose of the stressor can induce protection. This phenomenon known as postconditioning has been documented 128 , 129 and is thought to be a form of temporal adaptive response possibly involving hormetic mechanisms where the time sequence of the 2 doses is less important than the fact that a small dose is administered.…”

Peer Review #1 of "Numerical ability and improvement through interindividual cooperation varied between two cyprinid fish species, qingbo and crucian carp (v0.1)"

“…Chinese crucian carp and 10 groups of 4 qingbo mixed with 5 Chinese crucian carp for stimulus shoal of 9 individuals. The positions of the test fish were analyzed by the automated tracking software program id Tracker (v 2.1) (Pérez-Escudero et al, 2014;Tang et al, 2017). In conspecific dyads, the video files of two of the measurements of 8 vs. 12 in qingbo, three of the measurements of 9 vs. 12 in crucian carp and one measurement of 10 vs. 12 in crucian carp failed to be decoded.…”

“…It is suggested that differences in numerical ability might exist in closely related fish species. This may be reasonable, as qingbo in the field prefer to live in fast-flowing water and exhibit a group-living lifestyle (Killen et al, 2016;Tang et al, 2017).…”