To browse Academia. Positive social interactions involving physical contact can decrease stress in vertebrates, including fish. This study examines the effects of tactile stimulation on the stress levels of surgeonfish C.
Results indicate that fish receiving increased tactile stimulation exhibited lower cortisol levels, suggesting that physical contact is a significant factor in stress reduction. The implications for understanding stress coping mechanisms in aquatic environments are discussed.
Study species and housing conditions. All surgeonfi sh C. Th ese individuals are detritivores with small home ranges, are frequent clients to cleaning stations and readily adapt to captivity conditions A total of 32 surgeonfi sh were kept in groups of fi ve to seven individuals in large, round holding tanks 1 m in diameter with fl owthrough seawater for a minimum of 15 days before being transferred to individual experimental aquaria Several polyvinylchloride pipes 15 cm long and 16 cm diameter served as shelter for the fi sh.
Th e experiments were conducted sequentially in 16 aquaria. Our study suggests that fi sh benefi t, in the form of reduced stress, from physical contact alone. We found that physical stimulation by a cleanerfi sh model lowered basal cortisol levels in two ways: fi rst, it reduced surgeonfi sh cortisol in controlled conditions regardless of exposure to a confi nement stressor; and second, among individuals with higher levels of stress confi ned group , variation in time previously spent receiving physical stimulation was signifi cantly related with a decrease in the impact of an acute stressor Fig.
Th is revealed that physical contact, without any social factor, is enough to produce positive short-term physiological eff ects in fi sh, a phenomenon so far demonstrated only in humans 5 Our results are thus in line with claims that the pathways for sensory information processing are more uniform among vertebrates than previously acknowledged Fish clients in the wild may combine this rewarding mechanism to a specifi c function: juvenile fi sh may learn to associate the seeking of cleaners and the receiving of physical contact to the relief of parasitism-derived tension or stress.
