Metabolic rate and aggressiveness between Brown Trout populations

Abstract

Summary1. Studies focusing on the physiological variation between populations and its connection to fitness-related traits are rare, even though integrating these fields would increase knowledge on the evolution of traits. Standard metabolic rate (SMR) has been suggested to influence an individual's social status and the level of aggressiveness, as dominant individuals tend to have higher SMR than subordinate individuals. 2. The SMR of juvenile Brown Trout (Salmo trutta) from four populations was measured, and the population-level relationship between SMR and aggressiveness, which is a fitness-related behavioural trait, was investigated. 3. SMR differed between the populations, but no differences were found in the amount of aggression. Nevertheless, a significant positive correlation between aggressiveness and SMR between the populations was found. 4. Unlike many previous studies on geographical variation of metabolic rate, SMR correlated negatively with the latitude of origin of the populations. 5. The results suggest that SMR and aggressiveness are correlated not only at the individual level as shown by previous studies, but also at the population level. The costs and benefits of high metabolic rate depend largely on the environment, and local differences in environmental conditions, as for example in food availability, may select for local differences in SMR.

Life‐history divergence facilitates regional coexistence of competing Ficedula flycatchers

“…However, there are several studies suggesting that aggression (often associated with high testosterone levels) trades off against a number of traits important for self-maintenance. Aggression has been shown to be associated with higher metabolic rate in Salmonid fish (Metcalfe et al 1995, Lahti et al 2002, which may lead to a trade-off between growth rate and aggression in certain environments (Vøllestad and Quinn 2003). In the literature on sexual selection, trade-offs between aggressive behavior, metabolic rate, and immune functions have received considerable theoretical and empirical attention (e.g., Maynard Smith and Harper 1988, Owens and Hartley 1991, Folstad and Karter 1992, Johnstone and Norris 1993, Owen-Ashley et al 2004).…”

Cultured Atlantic salmon in nature: a review of their ecology and interaction with wild fish

“…Moreover, farmed salmon, selectively bred over several generations for production traits such as fast growth, differ genetically from their wild origin (Gjedrem, 2000;Weber and Fausch, 2003), with greater production rates of growth hormone, for example (Fleming et al, 2002). Fast growth is linked to enhanced appetite and greater risk taking (Fleming et al, 2002), and elevated standard metabolic rate (Metcalfe et al, 1995;Cutts et al, 2002;Lahti et al, 2002). Hybrid juveniles are often intermediate in their expression of characteristics between farmed and wild juveniles (McGinnity et al, 1997(McGinnity et al, , 2003Fleming et al, 2000).…”

Modelling brown trout spatial requirements through physical habitat simulations

“…Moreover, territoriality is a flexible rather than a rigid behaviour strategy (Grant, 1997), varying between individuals and populations. Variations in abiotic characteristics such as instream physical habitat features (Johnsson et al, 2000Höjesjö et al, 2004) or food availability (Brännäs et al, 2003) between rivers, as well as behavioural differences, resident-migratory behaviour (Lahti et al, 2001) or aggressiveness level (Lahti et al, 2002), between populations may cause changes in brown trout territorial behaviour and spatial ecology. In the present study, YOY fish scaled territories to body length and mass at a rate similar to other populations of brown trout and different species of salmonids, while older trout did it at a significantly lower rate than those formerly described in salmonid species.…”