A meta‐analysis of fish behavioural reaction to underwater human presence

Abstract

In an increasingly anthropic world, humans have profound impacts on the distribution and behaviour of marine fishes. The increased human presence has modified fishes’ antipredator behavioural responses, and consequently flight decisions, as a function of their changed perceptions of risk. Understanding how fish react to human presence can help identify the most vulnerable functional groups/species and estimate impacts caused by human disturbance. Shoal and body size are known to influence fish flight initiation distance (FID; the distance between the predator and prey when the prey begins to escape); however, few studies attempt to test the moderators of these relationships. Here, we present a comprehensive meta‐analysis evaluating FID of fish in response to human presence. Specifically, we investigated six candidate moderators that could influence the relationship between FID with shoal and body size. Our results showed that individual fish size was strongly and positively correlated with FID and the most important moderator that explained the variance in individual body size‐FID relationship was shoaling behaviour. However, and somehow surprisingly, we detected no significant relationship between shoal size and FID. We discuss how these results can inform the development of fish conservation strategies and ultimately assist in the management of marine protected areas.

Client reef fish tolerate closer human approaches while being cleaned

“…An explanation for the lack of a relationship is that in isolated oceanic islands, humans may not be directly recognized as predators by the fish. On the other hand, we could also expect that larger prey would have tolerated closer approach from predators than small prey, at both intra‐ and interspecific levels (Samia et al , 2019). Our results provide additional evidence that human threats modulate the relationship between body size and FID (Januchowski‐Hartley et al , 2011).…”

“…The theory of animal escape behavior predicts that individuals assess risk associated with a predatory encounter and trade off the costs versus the benefits of fleeing (Cooper, 2008). There is growing literature on how humans modulate risk perception in fishes and thus have impacts on FID as well (Samia et al , 2019). Such escape behavior data have helped us understand the fundamental trade‐offs animals make as well as the impacts of human disturbance on fish assemblages.…”

Evolutionary dynamics in the Anthropocene: Life history and intensity of human contact shape antipredator responses

“…Behaving excessively cautiously when there are no longer any predators around might be especially costly for herbivores who allocate considerable time foraging on relatively low-quality food resources [45]. Similarly, solitary species, like solitary individuals, cannot rely on conspecifics for protection and may need to allocate substantial time to antipredator behavior, as exemplified in mammals [46], birds [47], and fishes [48]. For solitary species, the loss of predators may lead to a more immediate loss than in social species, for which vigilance may have social functions as well as antipredator functions and thus be retained under relaxed selection.…”

Incorporating reef fish avoidance behavior improves accuracy of species distribution models

“…Reproductive value often increases with size in fishes (Birkeland & Dayton, 2005), and theory predicts that risk-taking should decrease at higher levels of reproductive value (Clark, 1994). In addition, larger fishes are often preferentially targeted by fishers and may have more experience with this threat, so are more willing to incur fleeing costs compared to smaller fishes (Tsikliras & Polymeros, 2014;Samia et al, 2019). Previous studies using flight initiation distance (FID) as a measure of fish wariness also showed a positive relationship with body length (Gotanda, Turgeon & Kramer, 2009;Januchowski-Hartley et al, 2011;Januchowski-Hartley et al, 2015;Bergseth et al, 2016).…”