Behavioural Defenses in Fish

Johnsson, J. I.

doi:10.1201/b10189-9

Cited by 2 publications

(2 citation statements)

References 133 publications

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“…Fish defence strategies are sometimes associated with physicochemical characteristics of water (Pinto et al., 2012). For example, defensive strategies involving reflective, cryptic, or mimicry coloration patterns can be effective defences against visually orienting predators when water transparency is high (Johnsson, 2009; Pinto et al., 2012). In the upper Paraná, non‐native species with other types of defences, such as spines, venom, or armour, were more common in the moderately altered river that had lower transparency.…”

Section: Discussionmentioning

confidence: 99%

Patterns of functional diversity of native and non‐native fish species in a neotropical floodplain

et al. 2022

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Human activities affecting freshwater ecosystems, such as regulation of rivers by dams and introduction of non‐native species, are recognised as major threats to freshwater biodiversity, with fish communities strongly impacted. We evaluated patterns of functional diversity of native and non‐native species in local fish assemblages in the upper Paraná River floodplain over a 33‐year period (1986–2019) in three rivers with different degrees of alteration by dams (highly altered, moderately altered, and little altered). We also examined the effect of non‐native species on functional diversity of native species and investigated the responses of functional traits of native and non‐native fishes in regions with different histories of flow alteration. We measured 13 functional traits associated with five niche dimensions: feeding, habitat use, metabolism, life history, and defence. Functional diversity was evaluated from functional richness, functional redundancy, and Rao's quadratic entropy. The effect of non‐native species on functional diversity indices of native species was evaluated using a simple linear regression between each index and the level of dominance by non‐native species. To evaluate changes in functional traits of native and non‐native species over time and among rivers, we performed an RLQ analysis. Functional richness and Rao's quadratic entropy of native species decreased over time, while functional redundance increased especially in the most altered river. The level of dominance by non‐native species was negatively associated with functional richness and Rao's quadratic entropy of native species. Native species that are migratory with high fecundity, single spawning events and large body size were most common during the first 2 decades and within the least altered river. Non‐native species with parental care, multiple spawning, relatively large eggs, and brood defence tended to have greater prevalence during the last 2 decades and within the moderately altered region. Comparison of temporal trends in the functional diversity and characteristics of native and non‐native fishes within regions of the upper Paraná River floodplain having different levels of environmental alteration suggests that non‐native species and alteration by dams interact to adversely impact the functional diversity of native fishes, with especially strong effects on migratory fishes with a periodic life history strategy.

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Section: Discussionmentioning

confidence: 99%

Patterns of functional diversity of native and non‐native fish species in a neotropical floodplain

et al. 2022

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“…In increasingly human-dominated landscapes, wildlife is facing new threats. Unlike with natural predators animals have co-evolved with and developed specific defense tactics against (Johnsson 2009), prey species may not necessarily had the time to adapt to threats and risks associated with a range of human-related activities. They therefore need to increasingly rely on their non-specific vigilance to sense the environment, and on their behavioural flexibility to adjust to new human-induced challenges (Van Buskirk 2012).…”

Section: Introductionmentioning

confidence: 99%

Behavioural adjustment of fish to temporal variation in fishing pressure affects catchability: an experiment with angled trout

Koeck

Wallerius

Arlinghaus

et al. 2020

Can. J. Fish. Aquat. Sci.

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In passive fisheries, such as angling, the fishing success depends on the ultimate decision of a fish to ingest the bait, based on an individual’s internal state, previous experience, and threat perception. Fish surviving capture by anglers are known to be less vulnerable, and catch rates usually quickly decline with increasing fishing effort. Previous theoretical models have thus suggested fishing closures as a means to recover responsiveness of fish to angling gear and maintain catch rates, yet empirical support remains limited. In a controlled replicated pond experiment, we evaluated the effects of temporal variation in fishing pressure on catch rates of rainbow trout (Oncorhynchus mykiss) by simulating short-term fishing closures. Fishing closures increased catch rates and population-level catchability by reducing threat perception at the population level and allowing released individuals to return to a vulnerable state. Our experimental results show that periodic fishing closures benefit catch rates but at the risk of aggravating the likelihood of overharvesting.

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Behavioural Defenses in Fish

Cited by 2 publications

References 133 publications

Patterns of functional diversity of native and non‐native fish species in a neotropical floodplain

Patterns of functional diversity of native and non‐native fish species in a neotropical floodplain

Behavioural adjustment of fish to temporal variation in fishing pressure affects catchability: an experiment with angled trout

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