Precision of ingestion time and evacuation predictors for individual prey in stomachs of predatory fishes

Andersen, Niels Gerner; Beyer, Jan

doi:10.1016/j.fishres.2007.12.007

Cited by 11 publications

(17 citation statements)

References 15 publications

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“…Estimates μ i of S 0.5 i,t i may however be obtained from lengths of suitable sections of the partially digested prey recovered from the sampled stomachs by use of corresponding length-mass relationships established from measurements on fresh prey. Andersen and Beyer (2008) demonstrated that the standard deviation σ m of the relative error (S 0.5 i,t i − μ i )μ −1 i (i.e. the coefficient of variation of μ i ) can be considered constant, and a generally representative value of 0.03 obtained from measurements on a variety of prey fishes, was adopted for four different lengths.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Andersen and Beyer (2008) used a simple individual-based model of the predator to describe the variability of gastric evacuation not accounted for by the deterministic cylinder model. They showed that the variance of ρ i,E could be described by (σ e ρ i,E ) 2 , and obtained the estimate 0.10 of the coefficient of variation σ e from gastric evacuation experiments on Atlantic cod, whiting and saithe (pollock) (Pollachius virens) fed a variety of prey fishes.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Considering the uncertainties of evacuation rate and initial prey mass, the variance of estimated ingestion time was included (Andersen and Beyer, 2008). Further, the applicability of the method to field situations in terms of precision and accuracy was evaluated by taking into account generalised variance estimates, bias caused by non-observable prey evacuated prior to stomach sampling, and sensitivity to estimated original length of other prey recovered as small remains from sampled stomachs.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Predicting ingestion times of individual prey from information about stomach contents of predatory fishes in the field

Andersen¹,

Beyer²

2008

Fisheries Research

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Section: Model Descriptionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Predicting ingestion times of individual prey from information about stomach contents of predatory fishes in the field

Andersen¹,

Beyer²

2008

Fisheries Research

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“…The CV value of 0.080 estimated from the voluntarily feeding fish by Andersen 14 ( Table 2) compared well with the estimate of 0.098 obtained from a variety of predatory gadoids and their fish prey. 15 This variation probably reflects the interindividual variation in gastric performance. Substantially higher values of CV were obtained from both groups of force-fed G. morhua, which may then be explained by an additional variability due to the suppressing effects of handling, anaesthetization and force-feeding on GER to which the individual fish responds differently.…”

Section: Discussionmentioning

confidence: 99%

Recovery of gastric evacuation rate in Atlantic cod Gadus morhua L surgically implanted with a dummy telemetry device

et al. 2011

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The current study investigated how the gastric evacuation rate (GER) was affected after surgically introducing dummies of a blood flow biotelemetry system into the abdominal cavity of Atlantic cod, Gadus morhua. Gastric evacuation experiments were performed two and 10 days postsurgery on surgically implanted and control G. morhua force-fed sandeel, Ammodytes tobianus. The results were compared with previously obtained estimates from unstressed conspecifics voluntarily feeding on a similar diet. After two days, GER was significantly lower in the group of fish with the dummy implants compared with the control group, but following 10 days of recovery no significant difference was seen between the two groups. The difference between implanted and control fish observed two days postsurgery may have resulted either from surgery, postsurgical stress and/or the presence of the implant. The conclusion is that 10 days of postsurgical recovery will stabilize GER in G. morhua, thus indicating that at this point the implant per se did not affect GER. Both the fish with surgical implants and controls in this study evacuated their stomachs much slower and with much higher interindividual variation compared with G. morhua feeding voluntarily on similar prey items. The lower GER and higher interindividual variation for force-fed fish indicate that handling, anaesthetization and force-feeding impair GER and that individual fish respond differently to the suppressing effects. Invasive procedures are often necessary for the physiologist to understand the mechanisms behind various physiological parameters. In fish, measurements of cardiovascular parameters such as blood flow and blood pressure involve handling, anaesthesia and surgical implantation of catheters and flow probes in and around vessels and sutures to close the incisions. In traditional laboratory experiments, standard bench top blood pressure and blood flow measuring units are used, which means that the animals are 'hardwired' to the equipment during the experiments. Catheters and leads from flow probes penetrate the body wall and increase the risk of infection. Furthermore, to prevent tangling and ripping of wires the animals are most often confined in small containers, which severely limit the range over which they can move with the risk of introducing confinement stress. The animals are usually left for 18 -48 h before experimentation is initiated, the main reason for such shorts periods being the high risk of infection after an extensive surgery.1 In cases where catheters are used, limits on the time where these will remain open may also be decisive. However, unless appropriate recovery time is ensured following surgical procedures and instrumentation, major concerns are the validity of data and ethical considerations. In a study on rainbow trout Oncorhynchus mykiss using bioelectric potential recordings to measure heart rate, fH (i.e. a non-invasive method) the fish were handled and then left to recover for at least three days after which their basal heart r...

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“…). This provides a simple description of the variability of gastric evacuation not accounted for by the square‐root function (Andersen & Beyer, ). The rate parameter ρ is hence considered the outcome of a normally distributed stochastic variable with the variance ( σρ ) 2 , where σ is the constant c.v. of ρ .…”

Section: Methodsmentioning

confidence: 99%

Modelling gastric evacuation in gadoids feeding on crustaceans

Andersen

Chabot²,

Couturier

2016

Journal of Fish Biology

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A mechanistic, prey surface-dependent model was expanded to describe the course and rate of gastric evacuation in predatory fishes feeding on crustacean prey with robust exoskeletons. This was accomplished by adding a layer of higher resistance to the digestive processes outside the inner softer parts of a prey cylinder abstraction and splitting up the prey evacuation into two stages: an initial stage where the exoskeleton is cracked and a second where the prey remains are digested and evacuated. The model was parameterized for crustaceans with different levels of armour fed to Atlantic cod Gadus morhua or whiting Merlangius merlangus and recovered from the stomachs at different post-prandial times. The prey species were krill Meganyctiphanes norvegica; shrimps and prawns Crangon crangon, Pandalus borealis, Pandalus montagui and Eualus macilentus; crabs Liocarcinus depurator and Chionoecetes opilio. In accordance with the apparent intraspecific isometric relationship between exoskeleton mass and total body mass, the model described stage duration and rate of evacuation of the crustacean prey independently of meal and prey sizes. The duration of the first stage increased (0-33 h) and the evacuation rate of both stages decreased (by a half) with increasing level of the crustacean armament in terms of chitin and ash. A common, interspecific parameterization of the model within each of the categories krill, shrimp and crab can probably be used if the contents of chitin and ash are similar among prey species per prey category. The model offers a simple way for estimating evacuation rates from stomach content data in order to obtain food consumption rates of wild fishes, provided that information about digestion stage of crustacean prey is available.

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Precision of ingestion time and evacuation predictors for individual prey in stomachs of predatory fishes

Cited by 11 publications

References 15 publications

Predicting ingestion times of individual prey from information about stomach contents of predatory fishes in the field

Predicting ingestion times of individual prey from information about stomach contents of predatory fishes in the field

Recovery of gastric evacuation rate in Atlantic cod Gadus morhua L surgically implanted with a dummy telemetry device

Modelling gastric evacuation in gadoids feeding on crustaceans

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