A shift in the habitat use pattern of a lentic galaxiid fish: an acute behavioural response to an introduced predator

Abstract

Despite potentially reducing predation mortality, behavioural responses of native species to introduced predators may still have sub-lethal impacts. In video-recorded laboratory trials, we examined the effects of introduced brown trout, Salmo trutta, on the short-term behaviour of a threatened, lake-dwelling galaxiid fish and confirmed a suspected diel pattern in habitat use by this species. We found that Galaxias auratus followed a distinct diel pattern in the use of complex habitats and open water, which was significantly altered by the presence of brown trout. In trials without the introduced predator, G. auratus used complex habitats (rocks or macrophytes) during the day, and open water during the night. In trials with brown trout present, G. auratus spent significantly less time in open water and rarely ventured out of the macrophytes. However, when given the option of using only rocky substrate or open water, which is the more common situation in the lakes to which this galaxiid is endemic, the fish reduced the amount of time they spent in the open water during the night, but still spent more time in open water than when macrophytes were available. Spending the daylight hours amongst the cover of rocks or macrophytes is most likely an adaptation to reduce the risk of predation by visual predators, and the pattern of reduced use of open water habitats in the presence of brown trout is an acute response to the close proximity of the introduced predator. The difference in the nocturnal use of macrophytes and rocks when trout are present may be related to differences in feeding opportunities or success within these habitats.

Recognition of non-native peacock bass, Cichla kelberi by native prey: testing the naiveté hypothesis

“…Prey did not approach predators in our study, possibly because they could correctly assess the level of risk, since prey are reluctant to approach more dangerous predators (Dugatkin and Godin 1992). Another common antipredator response is a shift in habitat use, most often manifested in the increased Sih 1987;Stuart-Smith et al 2008). In our study, prey did not increase their use of vegetation in the presence of predatory cues.…”

“…These authors define naiveté more generally as lack of effective antipredator defenses, but argue that lack of predator recognition may be the most serious form of prey naiveté. Species extinctions after introduction of predatory fish (e.g., Nile perch, Witte et al 1992; peacock bass, Zaret and Paine 1973) indirectly support this hypothesis, and several studies report lack of introduced predator recognition by native prey (Shave et al 1994;Kiesecker and Blaustein 1997;Smith et al 2008 but see Nannini and Belk 2006;Stuart-Smith et al 2008). In order to test the naiveté hypothesis, prey responses to a novel predator type need to be compared to responses to a native predator.…”

Estimating activity-specific energy expenditure in a teleost fish, using accelerometer loggers

“…Trade-offs between the cost and benefit of specific behaviours govern the success and survival of animals through natural selection. For example, for many species of fish the choice of being active or inactive at different times of the day will affect both feeding success (Bestley et al 2008, Murphy et al 2011) and the risk of predation (Stuart-Smith et al 2007, Béguer-Pon et al 2012. Measuring the energy turnover and ways in which energy is allocated to specific activities is therefore of central importance in our understanding of behavioural and physiological ecology.…”

Finely tuned response of native prey to an invasive predator in a freshwater system

“…Support for this view is found in several studies reporting a lack of recognition of invasive predators by native prey that lack an evolutionary history with the predator (Shave et al 1994, Kiesecker and Blaustein 1997). However, both invertebrate and vertebrate prey have been shown to respond effectively to invasive predators in freshwater (Nannini and Belk 2006, Stuart-Smith et al 2008, Bourdeau et al 2011, marine (Freeman and Byers 2006), and terrestrial (Carthey and Banks 2012) systems. For example, native prey fish in relatively isolated rivers and marshes have been shown to respond appropriately to nonnative predatory fish, despite no previous history with them (Rehage et al 2009, Kovalenko et al 2010, DunlopHayden and Rehage 2011.…”