Response of juvenile rainbow trout to varying concentrations of chemical alarm cue: response thresholds and survival during encounters with predators

2003 ◽  
Vol 81 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Reehan S Mirza ◽  
Douglas P Chivers
Keyword(s):  
Rainbow Trout ◽  
Predation Risk ◽  
Time Frame ◽  
Behavioural Response ◽  
Response Threshold ◽  
Behavioural Responses ◽  
Juvenile Rainbow Trout ◽  
Chemical Alarm Cue ◽  
Alarm Cue ◽  
Risk Of Predation

Prey animals may mediate the intensity of their behavioural responses to predators to reflect their risk of predation. However, in the absence of an overt (observable) behavioural response to a particular predation-risk cue, we need to ask whether or not prey animals are still using the cue to assess predation risk. Behavioural responses that are not readily observable within the time frame of the experiment are considered covert. In this study we exposed juvenile rainbow trout, Oncorhynchus mykiss, to varying concentrations of conspecific chemical alarm cue to determine their observable response threshold. In a subsequent experiment we exposed the trout to alarm-cue concentrations above and below their behavioural-response threshold and allowed them to interact with an unknown predator (northern pike, Esox lucius). Trout exposed to concentrations below the observable response threshold were able to evade the predator equally as well as trout exposed to alarm-cue concentrations above the observable response threshold. This study illustrates the sophistication with which prey animals employ chemosensory risk assessment. We must use caution when relying on overt behavioural responses for assessing whether prey are utilizing specific cues to mediate their risk of predation.

Behavioural responses of voles to simulated risk of predation by a native and an alien mustelid: an odour manipulation experiment

2010 ◽  
Vol 37 (4) ◽  
pp. 273 ◽  
Author(s):  
Karen Fey ◽  
Peter B. Banks ◽  
Hannu Ylönen ◽  
Erkki Korpimäki
Keyword(s):  
Baltic Sea ◽  
Predation Risk ◽  
Myodes Glareolus ◽  
The Baltic Sea ◽  
Short Term ◽  
Behavioural Responses ◽  
Alien Predator ◽  
Risk Of Predation ◽  
The Baltic ◽  
The Impact

Context. Potential mammalian prey commonly use the odours of their co-evolved predators to manage their risks of predation. But when the risk comes from an unknown source of predation, odours might not be perceived as dangerous, and anti-predator responses may fail, except possibly if the alien predator is of the same archetype as a native predator. Aims. In the present study we examined anti-predator behavioural responses of voles from the outer archipelagos of the Baltic Sea, south-western Finland, where they have had no resident mammalian predators in recent history. Methods. We investigated responses of field voles (Microtus agrestis) to odours of native least weasels (Mustela nivalis) and a recently invading alien predator, the American mink (Mustela vison), in laboratory. We also studied the short-term responses of free-ranging field voles and bank voles (Myodes glareolus) to simulated predation risk by alien mink on small islands in the outer archipelago of the Baltic Sea. Key results. In the laboratory, voles avoided odour cues of native weasel but not of alien mink. It is possible that the response to mink is a context dependent learned response which could not be induced in the laboratory, whereas the response to weasel is innate. In the field, however, voles reduced activity during their normal peak-activity times at night as a response to simulated alien-mink predation risk. No other shifts in space use or activity in safer microhabitats or denser vegetation were apparent. Conclusions. Voles appeared to recognise alien minks as predators from their odours in the wild. However, reduction in activity is likely to be only a short-term immediate response to mink presence, which is augmented by longer-term strategies of habitat shift. Because alien mink still strongly suppresses vole dynamics despite these anti-predator responses, we suggest that behavioural naiveté may be the primary factor in the impact of an alien predator on native prey. Implications. Prey naiveté has long been considered as the root cause of the devastating impacts of alien predators, whereby native prey simply fail to recognise and respond to the novel predation risk. Our results reveal a more complex form of naiveté whereby native prey appeared to recognise alien predators as a threat but their response is ultimately inadequate. Thus, recognition alone is unlikely to afford protection for native prey from alien-predator impacts. Thus, management strategies that, for example, train prey in recognition of novel threats must induce effective responses if they are expected to succeed.

Behavioural Responses by Red-backed Salamanders to Conspecific and Heterospecific Cues

Behaviour ◽  
2003 ◽  
Vol 140 (4) ◽  
pp. 553-564 ◽  
Author(s):  
Aaron Sullivan ◽  
Jason Rohr ◽  
Dale Madison
Keyword(s):  
Predation Risk ◽  
Related Species ◽  
Chemical Cues ◽  
Plethodon Cinereus ◽  
Phylogenetic Relatedness ◽  
Behavioural Responses ◽  
Alarm Cue ◽  
Predation Event ◽  
Plethodontid Salamanders ◽  
Desmognathus Ochrophaeus

AbstractChemical cues released from injured prey are thought to indicate the proximity of a predator or predation event, and therefore, an area of elevated predation risk. Prey often avoid chemical cues released from injured heterospecifics, but there is little evidence to determine whether this is due to homologous cues among phylogenetically related species, or avoidance of injured syntopic species that experience predation from the same predators. The purpose of this study was to examine the response of terrestrial red-backed salamanders (Plethodon cinereus) to chemical cues from non-injured and injured members of their prey guild that vary in their relatedness to P.cinereus. In the laboratory, P.cinereus avoided chemical cues from injured conspecifics, injured and non-injured slimy salamanders (P.glutinosus), and injured confamilial dusky salamanders (Desmognathus ochrophaeus). Red-backed salamanders did not avoid rinses from non-injured conspecifics and dusky salamanders, or cues from injured and non-injured earthworms (Lumbricus sp.), a more distantly related prey guild member. These results cannot be fully explained by either phylogenetic relatedness (among plethodontid salamanders) or prey guild membership alone. We suggest that a combination of these factors, and perhaps others, likely influenced the evolution of heterospecific alarm cue avoidance in the red-backed salamander.

Embryonic exposure to a conspecific alarm cue triggers behavioural plasticity in juvenile rainbow trout

2017 ◽  
Vol 133 ◽  
pp. 35-45 ◽  
Author(s):  
Amandine Poisson ◽  
Claudiane Valotaire ◽  
Frédéric Borel ◽  
Aline Bertin ◽  
Anne-Sophie Darmaillacq ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Behavioural Plasticity ◽  
Juvenile Rainbow Trout ◽  
Alarm Cue ◽  
Embryonic Exposure

scholarly journals Graded Incorporation of Defatted Yellow Mealworm (Tenebrio molitor) in Rainbow Trout (Oncorhynchus mykiss) Diet Improves Growth Performance and Nutrient Retention

Animals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 187 ◽  
Author(s):  
Paulo Rema ◽  
Subramanian Saravanan ◽  
Benjamin Armenjon ◽  
Constant Motte ◽  
Jorge Dias
Keyword(s):  
Body Composition ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Growth Performance ◽  
Tenebrio Molitor ◽  
Nutrient Digestibility ◽  
Protein Meal ◽  
Yellow Mealworm ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficients of dry matter, protein, fat, phosphorus, and energy. Protein, phosphorus, and energy retention significantly increased in fish fed the diets with an insect protein meal. In conclusion, the yellow mealworm protein meal could effectively replace 100% of fishmeal in the diet of juvenile rainbow trout with positive effects on its overall zootechnical performance.

Sublethal effects of terbium and praseodymium in juvenile rainbow trout

2021 ◽  
pp. 146042
Author(s):  
Houda Hanana ◽  
Zofia E. Taranu ◽  
Patrice Turcotte ◽  
Christian Gagnon ◽  
Joanna Kowalczyk ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Sublethal Effects ◽  
Juvenile Rainbow Trout

scholarly journals Video surveillance methods to evaluate individual feeding response in rainbow trout (Oncorhynchus mykiss, Walbaum)—implications for feeding regime optimisation

2021 ◽  
Author(s):  
Philip Niclas Just ◽  
Bernd Köllner ◽  
Matthew James Slater
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Video Surveillance ◽  
Average Weight ◽  
Short Term ◽  
Feeding Regime ◽  
Daily Feeding ◽  
Juvenile Rainbow Trout ◽  
Feeding Regimes ◽  
The Impact

AbstractPrecisely analysing and optimising feeding regimes is central to salmonid growth performance and delivery of special diets. The current study developed novel video surveillance methods and analysis techniques to assess individual feed intake and minimum pellet intake (MPI) in individually identified juvenile rainbow trout, Oncorhynchus mykiss. Three trials were conducted to test the impact of short-term starvation (N=112 [16 tanks, 7 fish per tank], average weight=27.1±3.4g, age= 119 days), portion numbers per feeding (N=105 [15 tanks, 7 fish per tank], average weight=22.8±2.1g, age= 99 days) and varied numbers of daily feeding events (N=84 [12 tanks, 7 fish per tank], average weight=32.4±3.3g, age= 133 days). All trails were carried out in a recirculating aquaculture system with 20 tanks held at 15 ± 0.5°C. All individuals were code-tagged and high quality video images were taken and analysed to identify all feeding interactions. Individual trout feeding activity under different feeding regimes could be precisely analysed with the video methods developed. Moving from one to two daily feeding events doubled pellet intake per fish from 27.4 ± 5.8 to 52.8 ± 11.5 pellets. Pellet intake (58.8 ± 24.2 pellets) did not increase at three daily feeding events but became more variable across fish. MPI nearly doubled to 30 pellets in fish receiving two daily feeding events (MPI30: chi-squared = 8.74, df = 2, p = 0.01). Short-term starvation had no influence on intake (28 ± 8 pellets/fish) or MPI. Increasing portion number from one (27.8 ± 7.4 pellets fish−1) to two (31.1 ± 7.4 pellets fish−1) or more did not significantly increase the number of ingested pellets. Adjusting the feeding regime by increasing daily feeding events to two, possibly combined with multiple portions, can increase pellet intake and reduce the heteroscedasticity of pellet intake. The methods presented in this study are viable for analysing feeding regimes for juvenile rainbow trout and controlled feedstock/supplement delivery. Implications for analyses with other species and for vaccination optimisation are discussed.

Changes in Habitat Use and Feeding Chronology of Juvenile Rainbow Trout (Oncorhynchus mykiss) in Fall and the Onset of Winter in Silver Creek, Idaho

1993 ◽  
Vol 50 (10) ◽  
pp. 2119-2128 ◽  
Author(s):  
Michael D. Riehle ◽  
J. S. Griffith
Keyword(s):  
Rainbow Trout ◽  
Habitat Use ◽  
Oncorhynchus Mykiss ◽  
Density Distribution ◽  
Stomach Contents ◽  
Early Morning ◽  
Invertebrate Drift ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

We assessed changes in density, distribution, and microhabitat of age-0 rainbow trout (Oncorhynchus mykiss) in Silver Creek, a partially spring-fed stream, by periodic snorkeling in August 1987 through January 1988. We examined trout stomach contents and invertebrate drift samples in diel collections in August, September, October, and January to test if the period of feeding shifted from daytime to nighttime, concurrent with a transition to day concealment. In late September, fish aggregated briefly during the day and then began to conceal themselves in macrophyte beds, undercut banks, and submerged sedges and grasses along streambanks as temperature dropped below 8 °C in early October. Fish emerged from concealment at night, and numbers of trout visible were greatest 30–60 min after sunset and about 30 min before sunrise. Periods of peak feeding changed from afternoon and evening in August and September, when fish were day active, to mainly at night in October after the initiation of day concealment. Trout did not feed upon abundant chironomids in the daytime drift in October. In January, fish fed at 1–4 °C on mayflies, and stomachs were fullest in the early morning. Observations suggest that Silver Creek trout experienced a metabolic deficit that began in September.

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