Calculates the rate \(E_i(w)\) at which a predator of species \(i\) and weight \(w\) encounters food (grams/year).
mizerEncounter(params, n, n_pp, n_other, ...)A matrix of species abundances (species x size).
A vector of the resource abundance by size
A list of abundances for other dynamical components of the ecosystem
Unused
A two dimensional array (predator species x predator size) with the encounter rates.
The encounter rate \(E_i(w)\) at which a predator of species \(i\)
and weight \(w\) encounters food has contributions from the encounter of
fish prey and of resource. This is determined by summing over all prey
species and the resource spectrum and then integrating over all prey sizes
\(w_p\), weighted by predation kernel \(\phi(w,w_p)\):
$$
E_i(w) = \gamma_i(w) \int
\left( \theta_{ip} N_R(w_p) + \sum_{j} \theta_{ij} N_j(w_p) \right)
\phi_i(w,w_p) w_p \, dw_p.
$$
Here \(N_j(w)\) is the abundance density of species \(j\) and
\(N_R(w)\) is the abundance density of resource.
The overall prefactor \(\gamma_i(w)\) determines the predation power of the
predator. It could be interpreted as a search volume and is set with the
setSearchVolume() function. The predation kernel
\(\phi(w,w_p)\) is set with the setPredKernel() function. The
species interaction matrix \(\theta_{ij}\) is set with setInteraction()
and the resource interaction vector \(\theta_{ip}\) is taken from the
interaction_p column in params@species_params.
The encounter rate is multiplied by \(1-f_0\) to obtain the consumption rate,
where \(f_0\) is the feeding level calculated with getFeedingLevel().
This is used by the project() function for performing simulations.
The function returns values also for sizes outside the size-range of the species. These values should not be used, as they are meaningless.
Other mizer rate functions:
mizerEGrowth(),
mizerEReproAndGrowth(),
mizerERepro(),
mizerFMortGear(),
mizerFMort(),
mizerFeedingLevel(),
mizerMort(),
mizerPredMort(),
mizerPredRate(),
mizerRDI(),
mizerRates(),
mizerResourceMort()