Potential impacts of invasive crayfish on native benthic fish: shelter use and agonistic behaviour

Spinycheek crayfish ( Faxonius limosus ) and signal Pacifastacus leniusculus are successful North American invasive species distributed throughout Europe. Both compete with native benthic fish for shelter. In a laboratory approach, we assessed competition shelter antagonistic interactions between these the species, stone loach Barbatula barbatula bullhead Cottus gobio ). This allows studying potential impacts of on fish. were able to gain control could successfully displace both species. For loach, presence significantly decreased their use caused several behavioural changes such as reduced activity increased hiding behaviour outside Although by bullheads was not reduced, they displayed similar changes, if less intense. Invasive showed remarkable combative against fishes, evidenced high number aggressive interactions, especially concerning loach. Our results highlight pronounced dominance over in terms under conditions, which consequently might promote latter’s exposure predation.