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Does short-term salinization of freshwater alter the behaviour of the Iberian barbel (Luciobarbus bocagei, Steindachner 1864)?

Leite, Tamara, Santos, José Maria, Ferreira, Maria Teresa, Canhoto, Cristina, Branco, Paulo
The Science of the total environment 2019 v.651 pp. 648-655
Luciobarbus bocagei, Luciobarbus comizo, Mediterranean climate, anthropogenic activities, ecological restoration, environmental hazards, fauna, fish behavior, freshwater, freshwater fish, salinity, salt stress, sodium chloride, streams
Stream salinization is a great environmental hazard being aggravated by anthropogenic disturbances. Harmful conditions, as increasing salinity in freshwater systems, may negatively affect river fish fauna and possibly influence fish behaviour, such as boldness and/or cerebral lateralization. Salinity has been proven to affect behavioural expression, despite the tolerance of some species. It is thus relevant to study these behaviours, as the salinity exposure effects could represent greater environmental consequences. The impact of salinity stress was evaluated by exposing Iberian barbels, Luciobarbus bocagei (Steindachner, 1864) (Cypriniformes, Cyprinidae), to three levels of salinity (0.9, 9 and 19 mS/cm, using NaCl) and by conducting boldness and lateralization experiments, regarding population trends. Results show that, with increased salinity, fish diverged to the extremes of the shy-bold gradient, the population was slightly lateralized to the left, and seemed to become more lateralized with increasing salinity. However, there were no statistical differences between the treatments. Fish living in a Mediterranean climate are especially resilient to various stressors, which may confer them additional tolerance, and in this case, acute punctual exposure to increased salinity may not be detrimental for behaviour maintenance. We encourage the expansion of the research to different freshwater fish species that would help to recognise salinity thresholds and use them to implement effective conservation measures and appropriate ecological restoration actions for these sensible systems.