Water temperature affects aggressive interactions in a Neotropical cichlid fish

Manuela L Brandão,Thaís B Carvalho,Roselene S Costa-Ferreira,Marcela C Bolognesi,Gisele Colognesi,Eliane Gonçalves-De-Freitas

doi:10.1590/1982-0224-20170081

Manuela L Brandão, Thaís B Carvalho + Show 4 more

Open Access

https://doi.org/10.1590/1982-0224-20170081

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Abstract

ABSTRACT Changes in water temperature may affect the aggressive behavior of aquatic organisms, such as fish, either by changing some physiological mechanisms or by increasing the probability of encounters between individuals as a result of variation in their swimming activity. In our study, we evaluated the influence of increasing and decreasing temperature on the aggressive behavior of the Neotropical cichlid fish Cichlasoma paranaense. Firstly, we tested the critical thermal maximum (CTMax) tolerated by this species. Then, we tested the effect of decreasing or increasing the water temperature in 6o C (starting at 27° C) on the aggressive interactions of fish under isolation or housed in groups. We found a CTMax value of 39° C for C. paranaense. We also observe that a 6° C decrease in water temperature lowers swimming activity and aggressive interactions in both isolated and group-housed fish, as expected. On the other hand, the increase in temperature had no effect on the fish’s aggressive behavior, neither for isolated nor for grouped fish. We concluded that C. paranaense shows high tolerance to elevated temperatures and, in turn, it does not affect aggressive behavior. Nevertheless, we cannot dismiss possible effects of elevated temperatures on aggressive interactions over longer periods.

Highlights

Environmental changes alter the physiology and behavior of animals, which allow them to deal with these new environmental conditions (Hofmann, Todgham, 2010; Wingfield, 2013)
We observed that critical thermal maximum (CTMax) was 39° C for isolated individuals, the social group was affected by aggressive interactions
For group-housed fish, we found that 37° C increases mortality within the group due to aggressive interactions, suggesting that an increase in both temperature and social aggression will increase mortality before fish can reach a CTMax under such conditions

Summary

Introduction

Environmental changes alter the physiology and behavior of animals, which allow them to deal with these new environmental conditions (Hofmann, Todgham, 2010; Wingfield, 2013). Such disturbances may be unexpected and demand immediate responses from individuals. For example, is a type of disturbance with immediate effects on aquatic environments, causing a rise in water temperature, light incidence, evaporation, and siltation (Matthews, MarshMatthews, 2003). Changes in temperature may quickly affect the physiology and behavior of aquatic animals such as teleost fish, changing their metabolic rates (Kochhann et al, 2015; Campos et al, 2017), impairing their reproduction and modifying the individuals’ personalities (Biro et al, 2010)

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