Species‐specific schooling behaviour of fish in the freshwater pelagic habitat: an observational study

Abstract

Social living of animals is a broadly occurring phenomenon, although poorly studied in freshwater systems, fish schooling behaviour is an excellent example. The composition of fish schools, species-specific schooling tendencies and preferences of adult fish were studied in the pelagic habitat of the Římov Reservoir, Czech Republic. Video recordings captured over a total of 34 days (16 h per day) in the clear water period of three seasons were analysed. From four species identified as schoolforming speciesbream, bleak, roach and perch, 40% of the individuals observed formed schools of 3-36 individuals. Although conspecific schools prevailed, 20% of individuals formed heterospecific schools, except bleak that schooled strictly with conspecifics. Schools were composed of individuals of similar body size and life strategy. Heterospecific schools were significantly larger than conspecific schools and showed uneven proportion among species, that is, one species being more abundant when the school dimension increased. Probability of encounter in bleak was lowest and proved highest inclination for schooling. Gregarianism levels depended on species morphology and body size, with larger and morphologically advanced fish tending less to sociability. This indicates that the antipredator function of schooling behaviour is intensified with increasing vulnerability of the species.

Spatial fish distribution in autumn in a shallow mesotrophic lake, assessed by hydroacoustic surveys, trawling, and beach seining

“…The shoaling behavior of fish during the day was captured by both hydroacoustics and trawling, and revealed another clear spatio‐temporal pattern (Holubová et al, 2020). Shoals were regularly observed by hydroacoustics and while different tows were unbalanced (in one too many fish, the next one practically empty), they were also evident in trawl catches (if the trawl hit the shoal, the catch was high, if not the trawl was empty).…”

A review and meta-analysis of the environmental biology of bleak Alburnus alburnus in its native and introduced ranges, with reflections on its invasiveness

“…Categorised as a 'compulsory schooling' species (Karst 1968) and an 'obligate schooler' (Haberlehner 1988), A. alburnus occurs almost exclusively in shoals, which commonly consist of 30-50 individuals (Holubová et al 2020) and move through the surface layer of the water column, usually at a depth not exceeding 1.5 m (Vašek et al 2009). Underwater observations demonstrated that adult A. alburnus shoals move rapidly (Karst 1968), positioned near the water's surface (Karst 1968;Vinyoles et al 2008), and that high swimming speeds preclude other species (e.g.…”

Computer Vision Reveals Fish Behaviour Through Structural Equation Modelling of Movement Patterns

“…The tracks for the evaluation dataset were selected at an ecologically relevant period of 30 min. We selected 30 min as it provides su cient nescale movement data from piped weirs for ecological research and management actions [73,74]. The training dataset had temporal buffers of 1, 5, 10, 15, 20, 30, 45 and 60 min.…”